Pelvic and vulvar varicose veins in women: clinical guidelines

List of Abbreviations

AVF – American Venous Forum

CEAP – Clinical, Etiological, Anatomical, Pathophysiological classification of chronic venous disorders

SVP – Symptoms-Varices-Pathophysiology classification of pelvic venous disorders

AV – arcuate veins

AMC – aortomesenteric compression

ARF – Russian Phlebological Association

PVD – pelvic venous disease

LEVD – lower extremity varicose veins

VV – vulvar varicosities

IIV – internal iliac vein

VVuV – vulvar varicose veins

LEVV – lower extremity varicose veins

PVV – pelvic varicose veins

GV – gonadal veins

DUS – duplex ultrasound scanning

LGV – left gonadal vein

LRV – left renal vein

UV – uterine veins

MRI – magnetic resonance imaging

MSCT venography – multislice computed tomography venography

IVC – inferior vena cava

EIV – external iliac vein

CIV – common iliac vein

PV – parametrial veins

PPR – pelviperineal reflux

RGV – right gonadal vein

PrV – perineal varices

RGV – gonadal vein resection

RCG – reno-caval gradient

RER – retroperitoneal endoscopic resection

rPelV – recurrent pelvic varices

rVVar – recurrent vulvar varices

MTS – May-Thurner syndrome

PCDS – pelvic congestion syndrome. PCDS: The term PCDS is recommended for use in patients with pelvic varices combined with chronic pelvic pain, the nature and severity of which vary.

NS – nutcracker syndrome

PVD – pelvic venous pain

PVR – pelvic venous reflux

PE – pulmonary embolism

TER – transperitoneal endoscopic resection

NP – nutcracker phenomenon

CVI – chronic venous insufficiency

CVD – chronic venous disease

CPP – chronic pelvic pain

GVE – gonadal vein embolization

GV – gluteal varices

Terms and Definitions

Pelvic varices – dilation (increase in diameter) of pelvic veins by more than 5 mm.

Pelvic varicosity (PV) – a condition characterized by dilation of intrapelvic veins (parametrial, uterine, arcuate, ovarian/gonadal, internal pudendal, obturator, inferior gluteal) with blood reflux through them.

Vulvar varices (vulvar varicose veins, VV) – dilation of the veins of the external genitalia.

Perineal varices (perineal varicose veins, PrV) – dilation of perineal veins outside the external genitalia.

Gluteal varices (GV) – dilation of veins in the gluteal region.

Venous obstruction – impaired patency of a venous segment.

Venous claudication – lower limb pain during physical exertion, often described as a dull, bursting pain in the thigh, buttock, or leg, not related to a specific walking distance or limited to a specific muscle group, and relieved by resting with elevated legs.

Dyspareunia – pelvic pain during or after sexual intercourse.

Main vein compression / compressive stenosis of a main vein – a pathological condition characterized by the compression of a vein by homologous arteries, leading to narrowing (stenosis) of the vein.

Objective symptoms of pelvic varices – visible manifestations of the disease, namely: dilated veins of the external genitalia, perineum, gluteal region, and lower limb edema.

Pelviperineal reflux (PPR) – retrograde blood flow from pelvic veins into superficial perineal veins via pelvic communicating veins.

Gonadal (ovarian) vein resection (GVR) – a surgical intervention consisting of the mobilization and removal of a segment of the gonadal vein.

Recurrence of pelvic (rPelV) and vulvar (rVVar) varices – the appearance of varicose veins after a completed course of invasive treatment in the area of the previous intervention.

Pelvic congestion syndrome (PCS) – a pathological condition arising against the background of intrapelvic vein dilation and characterized by pelvic venous pain, coital and postcoital pain, a sensation of heaviness and discomfort in the hypogastric region, and voiding dysfunctions.

May-Thurner syndrome (MTS) – compression of the left or right common iliac vein between the 5th lumbar vertebra and the right common iliac artery.

Nutcracker syndrome (NS, aortomesenteric compression [AMC] of the left renal vein) – compression of the left renal vein (LRV) between the superior mesenteric artery and the aorta, leading to left-sided renal phlebogenic hypertension.

Subjective symptoms of pelvic varices – complaints caused by pelvic varices, namely: pelvic pain, a feeling of heaviness and discomfort in the hypogastric region, pain during sexual intercourse (dyspareunia), and voiding dysfunctions. These symptoms are not pathognomonic.

Pelvic veins – gonadal, parametrial, uterine, arcuate veins, and tributaries of the internal iliac veins.

Pelvic venous disorder (PVD) – a condition that may be characterized by pelvic pain, dilation of pelvic, vulvar, and lower limb veins, as well as pain and edema.

Pelvic venous pain (PVP) – non-cyclic pain lasting more than 6 months, arising against the background of intrapelvic vein dilation, localized in the pelvic region, reducing the patient's quality of life, and requiring medical or surgical treatment.

Pelvic venous reflux (PVR) – impairment of the valve apparatus of intrapelvic veins, characterized by the appearance of retrograde blood flow in the vein.

Nutcracker phenomenon (NP) – compression of the LRV between the superior mesenteric artery and the aorta without the development of left-sided renal phlebogenic hypertension.

Chronic venous insufficiency (CVI) – a pathological condition caused by impaired venous outflow from the lower limbs, manifesting as moderate or severe edema, skin and subcutaneous tissue changes, and trophic ulcers (Classes C3–C6 according to CEAP).

Chronic venous diseases (CVD) – all morphological and functional disorders of the venous system. The main nosological forms of CVD are lower limb varicose veins, lower limb post-thrombotic syndrome (PTS), angiodysplasias (phlebodysplasias), telangiectasias, reticular varices, and phlebopathies.

Chronic pelvic pain (CPP) – non-cyclic pain lasting more than 6 months, localized in the pelvic region, not associated with pregnancy or the menstrual cycle.

Gonadal (ovarian) vein embolization (GVE) – endovascular occlusion of the gonadal vein using mechanical (endovascular microcoils for embolization (323500 cerebral vessel embolization coil***), vascular occluders (178270 cardiac occluder***)) and chemical (vein-sclerosing agents for local injections, 323520 cerebral vessel embolization material***) agents.

Gluteal varices (GV) – dilation of superficial veins of the gluteal region.

1. Brief information on the disease or condition

1.1 Definition of the disease or condition

Pelvic varices (PV) – a chronic disease with primary or secondary non-thrombotic dilation of pelvic veins, which can lead to the development of pelvic congestion syndrome (pelvic venous pain, heaviness and discomfort in the hypogastric region, dyspareunia, voiding dysfunctions).

Vulvar varices (VV) – dilation of the veins of the labia majora and minora and the vaginal vestibule, resulting from retrograde blood flow from intrapelvic veins into perineal veins (pelviperineal reflux).

1.2 Etiology and pathogenesis of the disease or condition (group of diseases or conditions)

Etiology

The causes of pelvic varices include repeated pregnancies and deliveries, May-Thurner and nutcracker syndromes [1-4]. Pregnancy is accompanied by significant changes in a woman's body that affect venous outflow from the pelvic organs. Among them, a significant (more than 70-fold) increase in progesterone levels, an increase in hemodynamic load on the pelvic veins due to increased arterial blood inflow to the uterus, and compression of the iliac and inferior vena cava by the gravid uterus should be highlighted [5,6]. The hormonal factor is the main cause of varicose transformation of pelvic veins. This fact is confirmed by the detection of uterine and adnexal varicose veins, as well as dilated vulvar veins in the early stages of pregnancy when the mechanical factor (compression of veins by the uterus) is excluded. Progesterone and estrogen receptors are present in pelvic veins, through which gestagens exert a negative effect on the venous wall. Progesterone has a venodilating effect and reduces venous tone [6-8]. Against this background, under conditions of increased hemodynamic load on the pelvic veins, the latter rapidly dilate, and pathological reflux forms within them.

Nutcracker syndrome leads to the development of left-sided renal venous hypertension of varying degrees of severity [9]. Regardless of the severity of renal venous hypertension, the mere presence of an obstruction to venous blood outflow through the LRV serves as a significant factor in collateralization of blood flow, with the left gonadal vein serving as the main venous collector through which retrograde blood flow occurs in nutcracker syndrome [10]. Thin-walled gonadal veins rapidly undergo varicose transformation. Iliac vein compression also causes an increased hemodynamic load on the internal iliac veins, their tributaries, and the gonadal veins [11,12].

Hormonal and hemodynamic factors are obvious causes of pelvic varices [1-3]. At the same time, pelvic varices are not observed in all multiparous women, and may be absent even in the presence of compressive stenoses of the LRV or common iliac vein. Obviously, the hereditary factor serves as the initial determinant for the formation of pelvic varices. The pathogenetic mechanisms of pelvic varices and lower limb varicose veins share common features, and the pathophysiological and biomolecular processes in these diseases do not have any significant differences [13,14,15].

Mechanisms of pelvic venous pain formation

The pathogenesis of pelvic pain development in patients with pelvic varices remains not fully understood [1,12,16]. One of the hypotheses regarding the occurrence of pain syndrome against the background of pelvic venous varicosity is the theory of venous wall inflammation caused by venous stasis [17,18]. Dilation and valvular incompetence of pelvic veins occurring under the influence of predisposing factors lead to impaired blood outflow from the pelvic organs and venous blood pooling within them, forming a pathological reflux that causes venous hypertension, which serves as one of the causes of venous pain due to nociceptor stimulation [19-23].

Changes in the vascular wall during varicose veins are also an additional triggering stimulus for the activation of pain receptors and the onset of pelvic venous pain (PVP) [1,24]. A decrease in blood flow velocity and blood stasis in the pelvic veins cause overstretching of the vessel wall. These changes and the associated hypoxia of the venous wall can trigger a cascade of biochemical processes contributing to the appearance of PVP [24,25].

The pathogenesis of PVP solely from the perspective of venous hemodynamic disorders cannot fully explain the cause of the pain syndrome. A study by DosSantos S. et al. (2015) [21] showed that the diameter of the gonadal veins should not be considered a predictor of gonadal vein reflux. Gavrilov S.G. et al. (2017) confirmed the absence of a correlation between the clinical manifestations of pelvic varices and the degree of pelvic vein dilation [22]. It is likely that for the development of PVP, in addition to hemodynamic disorders, inflammatory processes in the venous wall are of significance. Connective tissue dysplasia and excessive synthesis of vasoactive neuropeptides may play an important role in the formation of pelvic pain and varicose veins syndrome [25-29].

Hemodynamic and biomechanical disorders cause endothelial dysfunction, leading to the release and activation of enzymes that trigger inflammation in the venous wall. This can cause further alteration of the vascular wall, maintain the inflammatory process, and affect nearby nerves, which together may contribute to the occurrence of PVP [26,30].

Dormandy J.A. et al. (1996) found that erythrocytes can displace leukocytes to the periphery, forcing them to "roll" along the endothelium of the venous wall (so-called leukocyte rolling) with already activated adhesion receptors at a speed significantly lower than that of freely circulating leukocytes [25]. Reversible leukocyte rolling on the endothelium, mediated by endothelial cell selectin group substances such as E-selectin and P-selectin and their ligands on leukocytes, is the first stage of leukocyte adhesion. The second stage, firm leukocyte adhesion on the endothelium, is mediated by the intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) located on endothelial cells, and their corresponding ligands on leukocytes—leukocyte function-associated antigen-1 (LFA-1) and very late activation antigen-4 (VLA-4) [32]. This causes the activation of endothelial cells, which is manifested by an increase in calcium concentration in their cytoplasm, which in turn leads to an increase in the activity of phospholipase A2. The activation of phospholipase A2 serves as one of the key mechanisms for the synthesis of inflammatory mediators such as bradykinin, prostaglandins E2 and D2, platelet-activating factor (PAF), and leukotriene B4. PAF increases the local activity of serotonin and histamine, causing increased adhesion of neutrophils to the venous endothelium. This process subsequently leads to the infiltration of the venous wall by active neutrophils [17,18]. The presence of neutrophils, monocytes, activated T-lymphocytes, the accumulation of macrophages and mast cells, the expression of cell adhesion molecules on the surface of leukocytes and endotheliocytes, and the synthesis of cytokines and prothrombotic factors objectively indicate an inflammatory process in the venous wall. Some pro-inflammatory mediators synthesized as a result of hypoxia (e.g., bradykinin) can activate nociceptors located in the venous wall and connective tissue forming the perivenous space [17]. The pain-inducing effect of bradykinin is potentiated by prostaglandin E2, which, although not an algesic itself, increases nociceptor sensitivity [18].

Blood pooling in the pelvic veins is accompanied by the release of endothelial factors that activate smooth muscle cells of the veins and cause vasodilation due to the release of nitric oxide (NO). The release of vasoactive neuropeptides from the walls of dilated pelvic veins is considered one of the mechanisms of PVP formation [1]. Extracellular ATP is capable of inducing NO-mediated vasorelaxation via G-protein-coupled P2Y purinoceptor subtypes. This agent has also been identified as an important mediator of various processes, including pain. It activates P2X purinoceptor subtypes, which are ligand-gated ion channels. Presumably, based on studies of dorsal root ganglion neurons, the P2X3 purinoceptor subclass mediates the nociceptive action of ATP on afferent nerves [28]. ATP is localized in sympathetic fibers with noradrenaline and indicates the presence of a purinergic component in neurotransmitter release induced by electrical stimulation [27].

The presence of the neuropeptide substance P (SP) in the endothelium of the ovarian vein [27] and the ability of SP to induce endothelium-dependent vasodilation of vessels [28] have been described. SP ensures the sensitization of nociceptors during tissue damage and is a central link in the mechanism of chronic pain formation. Released from peripheral nerves, this neurotransmitter increases vascular endothelial permeability, T-cell proliferation, mast cell activation, histamine release, and leukocyte chemotaxis [29]. It is believed that the sensory function of SP is associated with the transmission of pain information to the central nervous system. A study by Yong Ma et al. (2014) showed that the plasma content of SP is significantly elevated in patients with chronic pelvic pain [33]. The role of calcitonin gene-related peptide (CGRP) in the development of neurogenic inflammation is indicated in a study by Kee et al. (2018), which noted the vasodilating effect of CGRP and its participation in the formation of pain syndrome [34]. A pilot study by Gavrilov et al. (2019) proved the correlation between the levels of vasoactive neuropeptides and the presence and severity of chronic pelvic pain in patients with pelvic pain and varicose veins syndrome [35].

1.3 Epidemiology of the Disease or Condition

To date, there are no large-scale epidemiological studies dedicated to pelvic varices. According to foreign researchers, the incidence of the disease is 15% among female patients of fertile age and 30% among women seeking medical care for chronic pelvic pain [36,37]. The incidence of compression stenoses of the left renal vein and left common iliac vein depends on the studied patient cohort (clinical or autopsy study results, general population, asymptomatic patients or patients with clinical manifestations of pelvic varices, pelvic pain and varicose veins syndrome, patients with a history of ileofemoral thrombosis), the research methods used (duplex ultrasound, multislice computed tomography, magnetic resonance imaging, phlebography, or intravascular ultrasound), and the degree of narrowing of the left common iliac vein. The detection of May-Thurner syndrome (MTS) based on autopsy results in the general population ranges from 14% to 32% [38-41]. In a study by Kibbe et al. (2004), narrowing of the left common iliac vein > 50% was detected in 24% of patients, and stenosis greater than 25% was diagnosed in 66% of examined asymptomatic patients [17]. Liu et al. reported the presence of MTS in 11% of symptomatic patients [18]. Among patients with pelvic varices, this syndrome is detected in 22-80% of patients [42-44]. Nutcracker syndrome is detected in 8-24% [45,46], and the nutcracker phenomenon in 37 to 45% [46,47] of observations. According to Ananthan et al. (2017), among patients with hematuria, 40% were found to have nutcracker syndrome [9]. Vulvar varicose veins are detected in 28-35% of patients with pelvic varices [48-50]. In pregnant women, vulvar varices are detected in 8-10% of observations [51].

Taking into account the available data, the prevalence of pelvic varices and vulvar varices is high among patients of working age, which indicates the high socio-economic significance of the problem.

1.4 Features of Coding the Disease or Condition

Pelvic varices I86.2

Varicose veins of vulva I86.3

Compression of veins I87.1

May-Thurner syndrome (compression stenosis of the left common iliac vein);

nutcracker syndrome/phenomenon (compression stenosis of the left renal vein).

1.5 Classification of the disease or condition

To date, there is no universally accepted classification of pelvic varices. The CEAP classification is not able to reflect all disorders and clinical manifestations of pelvic venous diseases. At the same time, the classification presented in the Russian clinical guidelines for the diagnosis and treatment of chronic venous diseases is successfully used in clinical practice [4]:

Classification of the Association of Phlebologists of Russia (2018)

by clinical manifestations:

• Pelvic congestion syndrome;

• Dilation of veins of the external genitalia (vulvar and perineal varices);

by course:

• Painful form;

• Painless form;

• Latent (asymptomatic) form.

by the extent of pelvic vein involvement:

• Isolated dilatation of pelvic venous plexuses (parametrial, uterine, arcuate);

• Combined dilatation of gonadal veins and pelvic venous plexuses;

• Unilateral or bilateral dilatation of gonadal veins;

• Dilatation of the trunk or tributaries of the internal iliac veins.

Aortomesenteric compression / compression stenosis of the left renal vein (Nutcracker phenomenon and syndrome)

Compression stenosis of the left common iliac vein (May-Thurner syndrome)

Example of diagnosis formulation according to the ARF classification

The patient sought medical care on 12.10.2021. Complains of lower abdominal pain, worsening in the second phase of the menstrual cycle, dyspareunia and pain lasting up to 1 hour after intercourse. Transabdominal and transvaginal duplex ultrasound scanning of pelvic veins was performed: renal and iliac veins without pathology, valvular insufficiency of the left and right gonadal veins, parametrial and uterine veins.

Diagnosis formulation according to the ARF classification:

Basic option: Pelvic congestion syndrome. Bilateral valvular insufficiency of the gonadal veins. 12.10.2021.

Full option: Pelvic congestion syndrome. Painful form. Bilateral valvular insufficiency of the gonadal veins, valvular insufficiency of the parametrial and uterine veins. 12.10.2021.

In 2021, foreign colleagues presented the first comprehensive classification of pelvic venous diseases – the SVP (Symptoms-Varices-Pathophysiology) classification [52]. It is based on dividing the retroperitoneal space, pelvis, and lower extremities into 4 zones (domains), assessing the presence of symptoms characteristic of pelvic venous disease, varicose veins in various anatomical areas, and the hemodynamic and pathophysiological features of disease development.

Symptoms-Varices-Pathophysiology Classification (2021)

PVD – pelvic venous disease; DVT – deep vein thrombosis

¹ – the CEAP classification should be used for a complete characterization of lower extremity symptoms and signs.

Example of diagnosis formulation according to the SVP classification

The patient sought medical care on 12.10.2021. Complains of lower abdominal pain, worsening in the second phase of the menstrual cycle, dyspareunia and pain lasting up to 1 hour after intercourse. Transabdominal and transvaginal duplex ultrasound scanning of pelvic veins was performed: renal and iliac veins without pathology, valvular insufficiency of the left and right gonadal veins, parametrial and uterine veins.

Basic version: Pelvic congestion syndrome with chronic pelvic pain due to bilateral ovarian reflux 12.10.2021.

Full version: Pelvic congestion syndrome with chronic pelvic pain due to bilateral ovarian reflux. C2 S2 PVD, R, NT (chronic pelvic pain of venous origin; pelvic varicosities; bilateral gonadal vein reflux of non-thrombotic origin). 12.10.2021.

1.6 Clinical presentation of the disease or condition

Clinical manifestations of pelvic varicosities are characterized by significant variability and non-specificity [4,53]. The most prominent symptom is chronic pelvic pain (CPP), which is constant, dull, and aching in character, localized in the lower abdomen, left and/or right iliac regions, worsens in the middle of the menstrual cycle, after prolonged static loads, heavy lifting, or use of progestogen drugs, and decreases after the patient rests in a horizontal position with elevated legs or with the use of venotonic drugs [54,55]. The presence of CPP indicates the development of pelvic congestion syndrome (PCS) and significant blood pooling in the pelvic veins. Another frequent sign of the disease is dyspareunia – pain during and after sexual intercourse [53,62]. The presence of dyspareunia indicates severe pelvic venous congestion. Heaviness and discomfort in the hypogastric region occurring during static and physical exertion are also frequent companions of pelvic varicosities [54]. Dysuric symptoms characterized by frequent urges to urinate are caused by venous congestion of the bladder wall [55]. Vulvar, perineal, gluteal varicosities, and varicosities of the posteromedial surface of the thigh are considered pathognomonic signs of internal iliac vein pathology, indicating the presence of blood reflux from the pelvic veins into the veins of the perineum and lower extremities [66]. Menstrual irregularities are often encountered in patients with pelvic varicosities, but their clear connection has not been proven, and this symptom is not considered specific for pelvic varicosities and PCS [55,235]. Patients with pelvic varicosities and PCS often exhibit symptoms of major depression, mood instability, irritability, and insomnia [101]. In a number of patients, pelvic varicosities are not accompanied by any symptoms, in which case the course of the disease is considered asymptomatic [22,5579]. In patients with nutcracker syndrome, characteristic features include left-sided flank pain [5,10], which is often combined with CPP [9]. May-Thurner syndrome combined with pelvic varicosities manifests with symptoms characteristic of PCS (CPP, dyspareunia, hypogastric discomfort, vulvar varicosities) [16,52].

2. Diagnostics, medical indications and contraindications for diagnostic methods

Criteria for establishing the disease or condition

The criterion for diagnosing symptomatic pelvic varicosities or PCS is the presence of clinical manifestations of the disease combined with pelvic vein dilation and reflux in them according to duplex ultrasound (DUS). In the case of an asymptomatic course of pelvic varicosities, the diagnosis is established based on the detection of pelvic vein dilation with reflux in them during DUS. The diagnosis of nutcracker syndrome is established based on clinical symptoms (CPP, left-sided flank pain), laboratory results (hematuria, proteinuria), DUS, and phlebography data indicating narrowing of the left renal vein lumen at the level of the SMA. The diagnosis of May-Thurner syndrome is established based on the presence of symptoms of pelvic varicosities and PCS, results of spiral computed tomography and phlebography, which reveal narrowing of the left common iliac vein lumen.

General Provisions on Diagnostics

• Patients with pelvic varicosities and lower extremity varicose veins are recommended to undergo a thorough clinical examination before applying imaging methods [4,53,54,55].

LNC 5 LeC C

Comments: clinical examination includes analysis of patient complaints, medical history taking, and physical examination (inspection and palpation), including assessment of local status. As a result of inspection, the presence of pelvic venous disease can only be suspected in the majority of patients. Due to the deep location of the pelvic veins, their objective assessment is possible only using instrumental research methods.

• All patients with chronic pelvic pain or suspected pelvic varicosities are recommended to undergo instrumental examination using ultrasound methods [4,53,54,57-62].

LNC 4 LeC C

• The diagnosis of pelvic varicosities is recommended to be established based on clinical symptoms with mandatory verification of morphological changes in the pelvic, iliac, and renal veins using imaging methods [4,24,54,63,64].

LNC 4 LeC C

Comments: the clinical course of pelvic varicosities includes symptomatic and asymptomatic courses; in the latter case, there are no anamnestic or physical indications of pelvic vein pathology. Considering the deep location of the pelvic veins and the impossibility of their visual assessment, verification of the diagnosis requires the use of instrumental research methods, primarily ultrasound examination [4,24,45,65]. Symptoms of pelvic varicosities have low specificity, and their severity and detection frequency vary significantly, which in turn also necessitates the use of diagnostic imaging tests in patients with a symptomatic course of the disease [65-67].

• All patients with chronic pelvic pain and suspected pelvic varicosities are recommended consultations with related specialists (urologist, obstetrician-gynecologist, neurologist, psychiatrist) in order to exclude/confirm non-venous pathology accompanied by chronic pelvic pain [1,4,54].

LNC 5 LeC C

2.1 Complaints and Anamnesis

One of the distinguishing features of pelvic varicosities is the absence of an obvious correlation between the clinical manifestations of the disease and the severity of morphological changes in the pelvic veins. Frequently, a significant increase in the diameter of the gonadal veins and pelvic venous plexuses, and reflux in these vessels, are not accompanied by any significant clinical symptoms or are absent altogether. Conversely, against the background of minimal pelvic varicosities, patients report severe pelvic pain and other symptoms of the disease. The reasons for this phenomenon are not entirely clear [1,68].

Asymptomatic course

• The diagnosis of an asymptomatic course of pelvic varicosities is recommended to be formulated in the absence of clinical symptoms of the disease against the background of pelvic vein dilation and reflux in them detected by DUS [1,4,69-71].

LNC 4 LeC C

Comments: in a significant number of women, dilation of the gonadal, parametrial, and uterine veins is discovered incidentally during routine pelvic ultrasound. Factors determining the presence of symptoms are the duration of pelvic venous reflux and its prevalence in various pelvic veins [71,72]. Varicose transformation of the pelvic veins is detected in 38–47% of women without symptoms of pelvic varicosities [73-75]. In some cases, due to certain characterological features of patients with pelvic varicosities, caused by elements of shyness or the taboo nature of discussing intimate issues, the latter are not always ready to actively inform the doctor about the symptoms of their disease. This fact can lead to false-negative diagnosis of the asymptomatic form of the disease. This dictates the need to actively elicit complaints characteristic of pelvic varicosities during the clinical examination of the patient by consistently asking leading questions [54,76].

Symptomatic course

• The diagnosis of a symptomatic course of pelvic varicosities is recommended to be established in the presence of characteristic complaints and visual signs specific to this disease in patients [4,54,63,77-79].

LNC 5 LeC C

Comments: Pelvic venous disorders (PVD) symptoms lack high specificity. The only pathognomonic sign of PVD is varicose veins of the perineum and vulva, which are found in 30–40% of patients [54, 76, 79]. Clinical manifestations typical of PVD are often encountered in various gynecological, urological, neurological, psycho-emotional, and other conditions, and may be caused by the aforementioned pathologies [65, 80, 81]. This circumstance frequently leads to the disease mimicking various clinical presentations [52, 82]. Depending on the localization of venous lesions in PVD and the involvement of major outflow pathways from the pelvic veins (renal, iliac veins), there are forms of PVD combining pathology of the pelvic, iliac, and renal veins, which have specific clinical differences due to the features of pathophysiological development mechanisms and vein morphology [83–85].

For a number of the indicated PVD symptoms and signs, the detection rate has been studied, and sensitivity, specificity, and predictive value indicators have been investigated. It should be taken into account that these data were obtained in studies with significant methodological limitations [37, 62]. The frequency of occurrence, sensitivity, and specificity of PVD symptoms are presented in Tables 1 and 2.

Table 1. Detection rate of various PVD symptoms [86]

Table 2. Sensitivity and specificity of symptoms in patients with PVD [62]

PPV – positive predictive value; NPV – negative predictive value.

Pelvic Congestion Syndrome (PCS)

• In patients with pelvic varicose veins and chronic pelvic pain of varying severity, it is recommended to use the term PCS when formulating the diagnosis [4, 54, 72, 87–91].

LNC 5 LeC C

Comments: the most prominent and dramatic symptom of PCS is chronic pelvic pain [4, 72]. It may manifest as a chronic pain syndrome or as coital and postcoital pain. The absence of pelvic pain should be considered as the absence of PCS. Pelvic varices or vulvar varices per se are not signs of pelvic congestion.

• Pelvic venous pain is recommended to be considered as a characteristic symptom of PCS [2, 4, 53, 54, 63, 64, 71, 82, 92, 93].

LNC 5 LeC C

Comments: pelvic venous pain (PVP) is dragging, aching, dull, or burning in character, localized in the hypogastric region or the left or right iliac region, radiating in 22–38% of cases to the inguinal regions, genitals, rectum, and lower extremities. The pain syndrome is non-cyclic, worsens with daytime orthostasis towards the end of the working day, prolonged sitting, heavy physical exertion, walking, overheating, and sexual intercourse, and is characterized by crises triggered by both exogenous (hypothermia, overwork, stress) and endogenous causes during exacerbations of chronic diseases. The severity of PVP decreases in the patient's supine position and with the intake of bioflavonoids, and conversely, increases with the use of progestogen hormones and related compounds. A feature of PVP is reaching its maximum intensity during menstruation, unlike endometriosis, where pain appears on the eve of menstruation. A frequent localization of pain is the ovarian projection, located in the middle third of the line between the umbilicus and the anterior superior iliac spine. Quantitative assessment of PVP is performed using the Visual Analog Scale (VAS) for pain and the Numerical Rating Scale (NRS) [16, 17, 19, 23, 30, 35], [Appendix G1 and G2]. To study the impact of PVP on patients' daily activity and performance, it is advisable to use the von Korff scale [36, 79, 171], [Appendix G3].

• Heaviness and discomfort in the hypogastric region are recommended to be considered as a characteristic symptom of PCS [64, 71, 79, 93, 94].

LNC 5 LeC C

Comments: these symptoms may be combined with abdominal pain or occur in isolation.

• Dyspareunia is recommended to be considered as a characteristic symptom of PCS [2, 64, 71, 92–95].

Level of Reliable Evidence 5, Grade of Recommendation C

Comments: the symptom manifests as pain during and/or after sexual intercourse, which can persist from 15 minutes to several days after intimacy, leading to disruption and fear of sexual relations, up to vaginismus. Deep dyspareunia, characteristic of PCS, and superficial dyspareunia, occurring in patients with vulvar varices, are distinguished.

• Dysuria is not recommended to be considered as a characteristic symptom of PCS [2, 54, 93, 94].

LNC 5 LeC C

Comments: the symptom includes painful and frequent urination, urinary incontinence, a sensation of incomplete bladder emptying, and frequent urges to urinate against the background of intensified PVP.

• Menstrual irregularities are not recommended to be considered as a characteristic symptom of PCS [2, 54, 95].

LNC 5 LeC C

Comments: the symptom includes painful periods preceded by a very distinct premenstrual syndrome, as well as dysmenorrhea manifesting as rhythm and duration disorders of menstruation in the form of prolonged, heavy, or irregular uterine bleeding.

• Psycho-emotional disorders are recommended to be considered as characteristic symptoms of PCS [24, 54, 74, 77, 101, 102].

LNC 5 LeC C

Comments: psycho-emotional disorders develop against the background of physical malaise and manifest as mood instability, irritability, insomnia, and symptoms of masked depression and anxiety. Depressive states are recorded in 25–50% of patients with PVD and PCS, anxiety in 10–20%, and psychosomatic complaints in 10–20% [101].

Nutcracker syndrome (aortomesenteric compression of the left renal vein, left renal vein compression stenosis)

Left renal vein (LRV) compression stenosis can exist in two clinical and morphological forms: nutcracker phenomenon and nutcracker syndrome. The nutcracker phenomenon (NCP) is not accompanied by significant changes in renal phlebohemodynamics, does not lead to renal venous hypertension and impaired left kidney function. This condition may cause the development of left gonadal vein valve incompetence and be accompanied by symptoms of pelvic venous congestion. Nutcracker syndrome (NCS) is characterized by hemodynamically significant compression of the LRV, the development of left-sided venous renal hypertension, and glomerular damage. As a result, symptoms and signs specific to this pathology arise.

• Pain in the left flank radiating to the buttock region, worsening with prolonged standing, sitting, or walking, is recommended to be considered as a characteristic symptom of NCS [5, 10, 45, 103, 104].

LNC 5 LeC C

Comments: the pathophysiological mechanism of the disease is associated with left-sided renal phlebohypertension and varicose veins of the renal pelvis with subsequent rupture of glomerular capillaries. Incompetence of the left ovarian vein, which begins to act as a "pathological" collateral compensatory renocaval shunt, leads to the formation of pelvic varicose veins.

• Migraine-like headaches are recommended to be considered as a characteristic sign of NCS [105].

LNC 5 LeC C

Comments: according to some authors [105–107] LRV compression stenosis is accompanied by varicose transformation of vertebral veins and epidural vessels. This, in turn, leads to venous congestion of the spinal cord and spinal nerves and is characterized by the formation of migraine-like headaches. In addition, individual studies have established an increase in plasma calcitonin gene-related peptide levels in patients with chronic pelvic pain of venous origin [27, 35]. Given the proven role of this neuropeptide in the development of migraine, it can be assumed that NCS combined with PCS may be accompanied by frequent, intractable headaches.

May-Thurner syndrome (MTS, compression stenosis of the left common iliac vein)

Compression of the left common iliac vein by the right common iliac artery (May-Thurner syndrome), compression of the right common iliac vein by the right common iliac artery, and compression of the left external iliac vein by the left external iliac artery are distinguished. Various combinations of the aforementioned venous compressions are possible.

Compression stenosis of the left common iliac vein (CIV) can lead to impaired venous outflow from the pelvic organs or lower extremities. Narrowing of the left CIV by more than 50% is considered hemodynamically significant stenosis [108,109], but this view has recently been questioned [110-112], which is confirmed by real clinical practice. It remains unknown why some patients with MTS present with symptoms and signs of chronic venous disease (CVD), while others manifest pelvic congestion syndrome (PCS). It is likely that the involvement of the left internal iliac veins, parametrial veins, uterine veins, and gonadal veins in MTS is a variant of disease development determined by genetic factors. On the other another hand, it can be assumed that due to the absence of a valve apparatus in the internal iliac veins in such patients, blood reflux initially occurred into the left internal iliac vein, thereby triggering a cascade of pathological changes in other veins. Be that as it may, MTS serves as an obvious morphological substrate for the emergence of pelvic varicose veins, the formation of reflux within them, and pelvic venous congestion [11,16]. Impairment of normal blood flow through the left CIV is accompanied by active collateralization of venous outflow from the pelvis. This manifests as dilatation of the left internal iliac vein, the formation of reflux along its trunk and tributaries, parametrial, uterine, and gonadal veins, and the left iliolumbar vein. Gonadal veins, acting as collaterals, probably suffer last; their dilatation and reflux are caused by an increase in hemodynamic load and an increased volume of blood flowing through these thin-walled vessels, which are not adapted to such intensive blood flow. Ultimately, pelvic vein dilatation and blood reflux through them lead to the development of PCS. A combination of pelvic and lower extremity vein involvement in MTS is also possible. In this case, patients additionally develop symptoms and signs of CVD.

• It is recommended to consider the characteristic signs of MTS as symptoms of PCS, either in isolation or combined with clinical manifestations of lower extremity CVD (varicose veins, heaviness, edema, pain, venous claudication, trophic disorders) [16,111-113].

LNC 5 LeC C

Comments: according to various data, the combination of MTS and PCS occurs in 4–80% of patients [16,110,114]. Such a significant range in the prevalence of this combination is most likely due to different approaches in evaluating clinical and phlebographic data. At the same time, authors share the consensus that MTS is an obvious factor in the development of PCS, and the clinical manifestations of left CIV compression stenosis are characterized by symptoms of pelvic venous congestion.

• The absence of clinical manifestations of MTS is recommended to be considered as a criterion for the hemodynamic insignificance of left CIV compression stenosis [110,115,116].

Level of Evidence 5, Grade of Recommendation C

Comments: several well-designed studies have proven the absence of any clinical signs of MTS in patients with significant, greater than 50%, narrowing of the left CIV [110-112,114-116]. This indicates that the clinical manifestations of the disease are caused not only and not so much by the narrowing of the left CIV, but by the involvement of pelvic or lower extremity veins in the pathological process, and the formation of pathological reflux in these vessels. This should be taken into account when using and evaluating the results of ultrasound examinations, computed tomography, magnetic resonance imaging, and pelvic phlebography.

Vulvar/perineal/gluteal varicosities

• Vulvar/perineal/gluteal varicosities are recommended to be considered as a pathognomonic sign of pelvic varicose veins [24,54,64,82,84,93,121,122].

LNC 5 LeC C

Comments: the occurrence of varicose veins in the aforementioned locations is caused by pelvoperineal reflux (PPR), which arises in the vast majority of cases during pregnancy [16,117,118]. Most frequently, PPR occurs via tributaries of the internal iliac veins (internal pudendal, obturator, and inferior gluteal veins). Blood reflux from intra pelvic veins into the superficial veins of the perineum, buttocks, and lower extremities may be a temporary phenomenon; for instance, it may disappear after childbirth, whereas varicose veins in the aforementioned locations persist [67,119]. In a number of patients, PPR persists after pregnancy and childbirth, causing the presence and progression of vulvar varicosities [99,120]. Numerous studies have proven the relationship between the veins of the pelvis, perineum, and lower extremities [49,50,51,123,124]. In 10–35% of cases, pelvic varicose veins are accompanied by blood reflux into the trunk and tributaries of the internal iliac veins, which manifests as the appearance of vulvar/perineal/gluteal varicosities and dilatation of veins on the posteromedial surface of the thighs [99,117,118,120]. All researchers share the opinion that visual identification of varicose veins in these locations serves as a pathognomonic sign of pelvic venous pathology.

• The clinical symptoms of vulvar varicosities are recommended to be considered as follows [16,67,99,117-121]:

– Varicose veins of the external genitalia;

– Pain in the labia area;

– Edema of the labia;

– Heaviness in the labia area.

LNC 5 LeC C

2.2 Physical Examination

• An objective (physical) examination is recommended for all patients with suspected pelvic varices [37,64,117,124].

LNC 5 LeC C

Comments: regardless of complaints and medical history, or the results of previous imaging studies, all patients should undergo an objective examination in both horizontal and vertical positions.

LNC 5 LeC C

LNC 5 LeC C

Comments: the prevalence of lower extremity varicose veins in patients with pelvic varices reaches 30-50% [84]. Pelvic varices can be a source of reflux into the lower extremities, leading to lower extremity varicose veins in 6% to 42% of cases [117,118,125].

LNC 5 LeC C

LNC 5 LeC C

Comments: characteristic signs of pelvic varices include increased sensitivity or tenderness of the vaginal walls, point tenderness without palpable induration over the ovaries or uterus on bimanual examination, and swelling of the cervix with tenderness upon palpation.

• Patients with pelvic varices are recommended to undergo a proctological examination (A01.19.004 digital rectal examination) [2,78,81].

LNC 5 LeC C

Comments: hemorrhoids are frequently detected in patients with pelvic varices due to shared anatomical and pathophysiological mechanisms of development.

2.3 Laboratory Diagnostics

Currently, there is insufficient information regarding specific laboratory tests to determine the venous origin of pelvic pain. Several studies have demonstrated increased concentrations of vasoactive neuropeptides (CGRP, SP, endothelin) and changes in lipid peroxidation in patients with pelvic congestion syndrome [27,28,35,128,130]. These data support the potential influence of neuropeptide activity on the onset of pelvic venous pain in patients with pelvic varices. However, the use of enzyme-linked immunosorbent assay (ELISA) in routine clinical practice is not advisable.

• Complete blood count and urinalysis (B03.016.006) are recommended for patients with left renal vein compression stenosis [9,10,52,105,131].

LNC 5 LeC C

Comments: patients with nutcracker syndrome may present with micro- and macrohematuria, as well as orthostatic proteinuria.

2.4 Instrumental Diagnostics

Duplex ultrasound scanning

Level of Evidence (LE) 2, Grade of Recommendation (GR) A

Comments: indications for pelvic vein duplex ultrasound (DUS) include chronic pelvic pain, detection of varicose veins of the external genitalia, gluteal, inguinal, and pubic regions, and non-saphenous varicose veins. DUS reliably detects pelvic vein dilation, pelvic venous reflux and its duration [5,54,71,120,135]. In a number of cases, this study is advisable for female patients with recurrent lower extremity varicose veins or non-saphenous varicosities to rule out pelvic venous pathology [4,5,136].

• Pelvic vein DUS (A04.12.022, duplex scanning of pelvic vessels) is recommended for assessing pelvic venous reflux (PVR) and its duration, vein patency, identifying vein dilation or narrowing, and determining blood flow velocity in veins [3,54,140-143].

Level of Evidence (LE) 4 | Grade of Recommendation (GR) C

Comments: the main purpose of DUS is to detect reflux in pelvic veins, its duration and extent within the pelvic veins (involvement of pelvic veins in the pathological process). Vein diameter is not a predictor of pelvic vein valve incompetence [21-23,71]. Assessment of the diameters of the left renal, common, external, and internal iliac veins is mandatory. Special attention should be paid to examining veins in typical zones of extravasal compression and measuring vein diameters along their course: for the left renal vein (LRV) — at the crossing point with the superior mesenteric artery and at the renal hilum; for the left common iliac vein (CIV) — at the crossing point with the right common iliac artery and caudal to this zone [71,135,140,144-146].

• During pelvic vein DUS (A04.12.022, duplex scanning of pelvic vessels), it is recommended to assess the state of the inferior vena cava, renal, gonadal, parametrial, uterine veins, common, external, and internal iliac veins and their tributaries [71,140,147-149].

LE 3 | GR C

• Pelvic vein DUS (A04.12.022, duplex scanning of pelvic vessels) is recommended using transvaginal, transabdominal, and translabial vein scanning [2,3,5,24,53,54,140,150,151,152].

LNC 5 LeC C

Comments: transvaginal DUS alone should not be used for diagnosing pelvic varicose veins; only the combined use of multiple ultrasound techniques can provide the most complete information on the state of the pelvic and retroperitoneal veins [24,71,151,153].

• During transabdominal DUS, it is recommended to examine the inferior vena cava, iliac, renal, and gonadal veins; measure the diameters of pelvic, iliac, and renal veins; measure peak systolic velocity (PSV), particularly in areas of arteriovenous conflicts; detect PVR using provocative tests and measure its duration; identify intraluminal or paravasal formations (thrombosis, post-thrombotic changes, lymph nodes, arterial aneurysms, etc.); and identify anatomical features of the pelvic, iliac, inferior vena cava, and renal veins (atypical course, vein hypoplasia or aplasia, collaterals, dextroposition) [3,71,140,147,150,153,154].

LNC 4 LeC C

• When performing transvaginal DUS (A04.12.022, duplex scanning of pelvic vessels), it is recommended to examine the internal iliac and gonadal veins, and venous plexuses (uterine, vaginal, ovarian); measure pelvic vein diameters; measure PSV; and determine PVR using provocative tests and its duration [71,132,139,140,143,150,153,154].

LNC 4 LeC C

• When performing translabial DUS, it is recommended to examine the perineal veins; measure vein diameters; detect reflux using provocative tests and its duration; and identify connections between perineal veins and pelvic and lower extremity veins [21,71,132,139,140,143,150,153,155].

LNC 5 LeC C

• When performing pelvic vein DUS (A04.12.022, duplex scanning of pelvic vessels), it is recommended to use a transabdominal convex transducer with a frequency of 3.5–5.0 MHz, a linear transducer with a frequency of 5.0–13.0 MHz, and an endovaginal microconvex transducer with a frequency of 4.0–9.0 MHz to accurately verify the diagnosis [2,4,71,137,138,148,153].

LNC 4 LeC C

• In female patients with pelvic varicose veins, DUS (A04.12.022, duplex scanning of pelvic vessels) is recommended to be performed in the supine position, semi-sitting position, and in the upright position with knees flexed (semi-standing) for better visualization of pelvic vessels [2,71,140,156].

LNC 5 LeC C

Comments: pelvic vein DUS is a dynamic examination; when performing it, it is recommended to use a medical couch with an adjustable head or foot tilt angle. Examination of upper abdominal veins is recommended in the semi-sitting position (30–80°), which simulates the typical hydrostatic pressure and gravitational forces necessary to assess hemodynamics and record reflux [140,153]. Examination of the iliac and gonadal veins is recommended with the patient in a semi-sitting position (up to 45°), which improves their visualization and prevents their collapse [2,140]. Performing the examination solely in the horizontal position reduces study quality, as reflux may disappear in this position due to the lack of sufficient gravitational force [149].

• During DUS of the pelvic, renal, and iliac veins (A04.12.022, duplex scanning of pelvic vessels), it is recommended to record vein diameters, blood flow velocity and its changes (decrease or acceleration, monophasic pattern, absence), PVR and its duration, vein patency, and the presence of intraluminal structures [133,141,153,157,158].

Level of Evidence (LE) 3, Grade of Recommendation (GR) C

Comments: measuring only pelvic vein diameters is insufficient, as this indicator does not affect the development of PVR and its duration [21,71,149,150]. In some patients, dilation of gonadal and/or parametrial veins is not accompanied by recorded PVR [159,161]. Blood flow velocity in pelvic veins is lower than in the iliac or major lower extremity veins; therefore, to perform a high-quality study, it is necessary to lower the color Doppler velocity scale threshold of the ultrasound scanner to 10–15 cm/s when examining gonadal veins and to 5–8 cm/s for pelvic venous plexuses [134,140,157,159,160]. To record blood flow in perineal veins, lowering the threshold to 3–5 cm/s is recommended [140]. In zones of arteriovenous conflicts, measurements of diameters and PSV are additionally performed at the crossing point of the artery and vein, before and immediately after the vein narrowing [154]. An increase in velocity after the stenosis zone by 2–2.5 times or more indicates a hemodynamically significant disorder (stenosis > 50%) [153,161]. PVR duration > 1 sec. should be considered pathological reflux [21,71,136,150,153,157]. Recording reflux in the gonadal veins is a more reliable indicator of pelvic congestion syndrome (specificity up to 100%) compared to their diameter (specificity 57–100%, sensitivity 67–95%) [153,157].

• To accurately assess PVR during DUS (A04.12.022, duplex scanning of pelvic vessels), it is recommended to use special provocative tests [3,24,54,71,140-142,149,153,159]:

— Valsalva maneuver (shallow inspiration and abdominal muscle straining);

– manual compression of the iliac region or the right hypochondrium;

– manual compression of the thigh.

LNC 4 LeC C

Comments: performing tests is recommended in a semi-sitting or semi-standing position simulating the patient's upright posture [3,140,142,149,159,163]. To detect reflux in perineal veins, in addition to standard provocation tests, the Kegel exercise (contraction of the pelvic floor muscles) or cough test may be used [140].

• To assess the severity of pelvic venous reflux during ultrasound examination of pelvic veins (A04.12.022, duplex scanning of pelvic vessels) in female patients with pelvic varicosities, it is recommended to distinguish the following grades [71]:

– Normal: up to 0.9 sec.;

– Type 1 (mild): 1 – 1.9 sec.;

– Type 2 (moderate): 2 – 5 sec.;

– Type 3 (severe): > 5 sec., or spontaneous reflux without stress tests.

LNC 4 LeC C

• The ultrasound signs of gonadal vein valve incompetence are recommended to be considered [3,4,21,54,71,133,139,141,148,149,159,160,163]:

– gonadal vein dilation > 5 mm;

– reflux along the gonadal vein for more than 1 sec.;

– low blood flow velocity (less than 3 cm/s) or retrograde blood flow;

– tortuosity and dilation of the pampiniform venous plexus > 5 mm.

LNC 5 LeC C

• The ultrasound signs of parametrial and uterine vein valve incompetence are recommended to be considered [3,4,21,54,71,133,139,141,148,149,159,160,163]:

– parametrial vein dilation > 5 mm;

– uterine vein dilation > 5 mm;

– reflux along the parametrial and uterine veins > 1 sec.;

– in case of unilateral parametrial vein involvement – increased peak systolic velocity on the unaffected side ("siphon" effect).

LNC 5 LeC C

Comments: dilation of uterine and parametrial veins can be detected by DUS in various pelvic organ diseases; therefore, identifying an increased pelvic vein diameter alone should not be considered a sign of PVD [155].

• It is recommended to consider the following as ultrasonic signs of hemodynamically significant compression stenosis of the left renal vein (nutcracker syndrome, NS) [9,71,104,138,145,146,154,165-167]:

– a decrease in the left renal vein diameter at the site of its crossing with the superior mesenteric artery compared to its diameter at the renal hilum (D_hilum/D_stenosis > 5, when examined in a semi-recumbent position – > 4);

– prestenotic dilation of the left renal vein;

– increased peak systolic velocity (PSV) in the stenosis area (PSV_stenosis/PSV_hilum > 4.9);

– PSV in the narrowing zone of more than 100 cm/s (may be more pronounced after the patient has been in a vertical position for 15 min.).

LNC 5 LeC C

Comments: DUS has a sensitivity of 50-90% and a specificity of 78-100% (in the presence of clinical symptoms) in determining NS [45,145,167]. Normally, the anteroposterior size of the left renal vein is 4-5 mm. At the same time, differences in the diameters of the distal and proximal sections can be detected in healthy individuals (in most cases > 50%) [45,145].

The severity of changes in the left renal vein diameter depends on the patient's position. In the horizontal position of the patient, positional compression of the vein will take place; to clarify the changes, measurements should be taken in a semi-recumbent or sitting position [45,104,164].

Nutcracker phenomenon and nutcracker syndrome (aortomesenteric compression of the left renal vein) should be differentiated. In patients with the nutcracker phenomenon (pseudonutcracker syndrome), the ratios of the left renal vein diameters in the hilum and vessel narrowing areas do not exceed 4, and the ratio of PSV in the stenosis zone and the renal hilum is no more than 4.9 [45,140,145,146].

Additionally, the angle and distance between the superior mesenteric artery and the aorta should be measured; normally, they are 51 ± 25º and 16 ± 6 mm, respectively [45,140,145,146].

Compression stenosis of the left renal vein is accompanied by the development of collateral outflow, dilation of the left gonadal vein, and blood reflux within it. This leads to the appearance of clinical manifestations of pelvic venous disorders and corresponding ultrasound signs (dilation of the left gonadal vein, veins of the pampiniform plexus and left parametrium, and the appearance of reflux in them) [45,150,153,168-170].

• It is recommended to consider a combination of the following signs as indirect ultrasound signs allowing to suspect May-Thurner syndrome (MTS) [154,166,173-183]:

– dilation of the left common iliac vein compared to the contralateral one;

– dilation of the left internal iliac vein and reflux in it > 1 sec.;

– dilation of the left gonadal, parametrial, and uterine veins and reflux in them > 1 sec.;

– change in blood flow velocity in the stenosis area compared to the initial segment (PSV_stenosis/PSV_prestenosis > 2.5),

– turbulent blood flow (mosaic pattern on color Doppler mapping) in the poststenotic segment of the left common iliac vein;

– monophasic blood flow in the narrowing zone without respiratory variations.

LNC 5 LeC C

Comments: DUS has low sensitivity (79%) in visualizing the iliac veins; adequate examination can be performed in only 20-50% of patients [174,175,180,183].

Compression stenosis of the left common iliac vein combined with left-sided iliofemoral thrombosis is known as Cockett syndrome [185].

Performing DUS in the vertical position is accompanied by a decrease in the degree of compression of the left common iliac vein, but there is no significant difference in diameters or PSV compared to the horizontal position of the patient [146].

The main tasks of DUS in evaluating the iliac veins in patients with pelvic varicose veins are detecting acute thrombosis or post-thrombotic changes in these vessels, and discovering dilation of the left internal iliac vein with reflux in it [166,183]. The absence of ultrasound signs of common iliac vein compression stenoses is not an absolute indicator of the absence of this pathology in patients with pelvic varicose veins [175].

Performing and interpreting the Valsalva maneuver during the examination of the iliac veins can be difficult due to the displacement of vascular elements and the presence of artifacts caused by bowel gas. At the same time, the absence of blood flow changes (its slowing, acceleration, or cessation) can be determined [166,174,177,180,183].

When measuring PSV, blood flow slowing and a change in the Doppler wave compared to the contralateral side, or its complete absence in the stenosis zone, can be detected [173,174,181,183].

Visualization of venous collaterals (iliolumbar vein, ascending lumbar vein) is important for diagnosis, but their assessment using DUS is difficult due to poor identification and various anatomical variations [178,187].

• It is recommended to perform DUS of the pelvic, iliac, and renal veins (A04.12.022, duplex scanning of pelvic vessels) in the early and late periods after surgical and endovascular interventions to assess the dynamics of their pelvic vein status (patency, diameters, reflux), and to detect postoperative vein and stent thrombosis [44,140,171,172].

LNC 4 LeC C

Multislice computed tomography (MSCT)

• MSCT (A06.12.055, computed tomographic angiography of pelvic vessels) is recommended as a diagnostic method for pelvic varicose veins confirmed by DUS data, as well as in case of a discordance between clinical and ultrasound examination results [2,4,79,180,188,190].

LNC 4 LeC C

Comments: MSCT is a reliable minimally invasive imaging method that allows studying the anatomical and topographical features of the pelvic and retroperitoneal veins with the ability to construct multiplanar reconstructions. Contrast-enhanced MSCT allows simultaneous assessment of the venous and arterial bed status [79,54,116,191,192]. The examination should be performed from the level of the diaphragm to the upper third of the thigh for the simultaneous assessment of the inferior vena cava, renal, gonadal, and iliac veins, and pelvic venous plexuses. MSCT allows assessing the condition of surrounding organs and tissues. Unlike MRI, it has low tissue contrast and does not allow a reliable assessment of the pelvic organs (uterus, prostate gland) [193,194]. The ability to construct multiplanar reconstructions increases the diagnostic value of the study. The method is associated with ionizing radiation and the use of iodine-containing X-ray contrast agents, which is a limitation for patients with renal failure [157,183,192-194]. Limitations and contraindications to CT venography associated with the use of iodine-containing X-ray contrast agents must be clarified before the procedure according to the current instructions for the drug posted on the website of the State Register of Medicines https://grls.rosminzdrav.ru [195]. There are still no clear recommendations on the methodology for performing contrast-enhanced MSCT [157,183,188]. Currently, the quality of the study depends on the experience and knowledge of the radiologist, the technical characteristics of the device, tactical approaches, and the availability of additional diagnostic methods in the medical institution [196]. MSCT results play an auxiliary role in determining treatment tactics.

Nutcracker syndrome/phenomenon

• MSCT (A06.12.055, computed tomographic angiography of pelvic vessels) is recommended as a diagnostic method for left renal vein (LRV) compression in the presence of clinical and laboratory signs of the disease [141,159,180,190,197,198].

LNC 4 LeC C

Comments: MSCT allows assessing variant anatomy of the renal and gonadal veins, anomalies of the inferior vena cava, detecting LRV compression stenosis, and the presence and severity of collateral venous blood flow [45,79,141,188,191,199,200]. Currently, there are no clear recommendations on the MSCT methodology; the possibility of obtaining high-quality visualization of the pelvic and retroperitoneal veins depends on the scanning protocol and technical features of the devices [157,183,188]. Unlike MRI, the scanning protocol in MSCT does not affect the assessment of variant anatomy [201-203].

• MSCT (A06.12.055, computed tomographic angiography of pelvic vessels) is recommended as a method for selecting patients for direct renal vein phlebography with measurement of the renocaval gradient or intravascular ultrasound [141,180,203-206].

LNC 4 LeC C

Comments: MSCT is a static study and does not allow for assessing the hemodynamic significance of left renal vein (LRV) compression stenosis [90,142,166]. The transverse dimensions of the vein, especially at the level of its compression, depend on body position, the phase of respiration, and the degree of hydration [2,45,166,200]. The prominence of the collateral network, the ratio of renal vein diameters at and proximal to the compression site, and the deformation of the venous lumen at the compression level can serve, to a certain extent, as indicators of the hemodynamic significance of LRV compression stenosis [159,180,200]. Detecting LRV compression stenosis and a pronounced collateral network (blood flow collateralization) allows for the selection of patients who require renal phlebography (A06.12.023, renal vein phlebography), phlebototonometry, or IVUS [159,180,200].

• When describing MSCT findings (A06.12.055, computed tomography angiography of pelvic vessels) in patients with LRV compression stenosis, it is recommended to indicate [198,200,202,204,206]:

– specific anatomical features of the renal veins, including the skeletotopy of the renal veins;

– the diameter of the LRV before and at the level of vessel compression by the superior mesenteric artery (SMA) during different respiratory phases;

– the angle of origin of the SMA from the aorta;

– the variant anatomy of the gonadal veins: number of trunks, their diameters, and variants of the gonadal-renal junction;

– anomalies of the IVC;

– presence or absence of thrombi in the renal and gonadal veins;

– presence or absence of luminal obliteration in the renal or gonadal veins;

– presence and prominence of the collateral venous network.

LNC 5 LeC C

May-Thurner syndrome

• MSCT (A06.12.055, computed tomography angiography of pelvic vessels) is recommended when May-Thurner syndrome (MTS) is suspected based on clinical examination or duplex scanning of the pelvic, iliac, and renal veins (A04.12.022, duplex scanning of pelvic organs) to determine the level, extent, and degree of iliac vein stenosis [16,116,180,189,207-213].

LNC 4 LeC C

Comments: MSCT makes it possible to evaluate the level, extent, degree, and cause (bone spurs, arteries, pathological masses) of compressive iliac vein stenosis [180,182,183,191,214-216]. At the same time, it should be considered that the respiratory phase and the patient's hydration status can influence the vein diameter in the compression zone [45,188,206,214].

• MSCT (A06.12.055, computed tomography angiography of pelvic vessels) is not recommended for assessing the hemodynamic significance of compressive iliac vein stenosis [2,115,142,175,188,208].

Level of Evidence (LE) 5, Grade of Recommendation (GR) C

Comments: MSCT is a static method performed in the supine position, which affects the severity of compression. The respiratory phase and the patient's hydration status also affect the vein diameter at the compression level [45,188,207,214]. The degree of iliac vein compression on MSCT is a variable value depending on a number of factors and cannot be a reliable indicator of stenosis severity and its hemodynamic significance. Data on the correlation between CT venography and IVUS results are extremely limited and have only been demonstrated for stenosis degrees greater than 50% [207,215]. If it is necessary to indicate compression/compression stenosis parameters, the cross-sectional area of the vein lumen should be measured rather than the anteroposterior dimensions at the compression level. The collateral network provides indirect evidence of the hemodynamic significance of iliac vein compression [159,180,183,207,213,214]. Venous lumen visualization depends on the technical characteristics of the scanner, the scanning protocol, and the selected time parameters [183,216]. This method is not used to evaluate the venous lumen at the compression level for the presence or absence of intraluminal adhesions (synechiae) [188].

• During MSCT (A06.12.055, computed tomography angiography of pelvic vessels) in patients with May-Thurner syndrome, it is recommended to indicate [180,183,190,214,215]:

– the level and extent of compression;

– the variant anatomy of the iliac veins;

– the diameter of the iliac veins before and at the level of compression, depending on the respiratory phase;

– the presence/absence of thrombi and obliteration of these vessels in the iliac veins;

– the presence and prominence of the collateral network;

Level of Reliability of Evidence 5, Level of Recommendation C

• MSCT (A06.12.055, computed tomography angiography of pelvic vessels) may be recommended to assess the efficacy of endovascular treatment for MTS [180,196,212].

LNC 4 LeC C

Comments: MSCT allows for the evaluation of changes in the diameters of the collateral network veins, which serves as an indicator of MTS treatment efficacy. MSCT is a method for assessing the patency of the stented venous segment. Unlike MRI, MSCT lacks artifacts that hinder the visualization of the lumen of the stented venous segment [56,180,191,196,212]. MSCT enables the visualization of stent deformation, dislocation, migration, and stent placement errors [2,15].

Pelvic venous congestion syndrome

• MSCT (A06.12.055, computed tomography angiography of pelvic vessels) is recommended as an additional topographical diagnostic method for PVCS following ultrasound verification of pelvic varices, identification of additional causes of pelvic vein dilation (compression of the LRV and iliac veins, IVC anomalies), and clarification of gonadal vein anatomy prior to surgical or endovascular intervention on the pelvic veins [2,79,189,190,203,205,217,218].

LNC 4 LeC C

Comments: MSCT is not a method for assessing the presence and duration of pelvic venous reflux. The method can be used to visualize dilated pelvic veins, accurately determine their diameter, and identify arteriovenous conflicts and other causes of pelvic vein dilation [180].

• MSCT (A06.12.055, computed tomography angiography of pelvic vessels) is recommended when planning surgical treatment for patients with PVCS [2,16,175,193,201,209,217].

LNC 5 LeC C

Comments: MSCT makes it possible to evaluate not only variant anatomy but also vein patency within the internal iliac vein basin. MSCT has advantages over MRI in visualizing small-caliber thrombosed veins [191,219]. The presence of metal hardware in the scanning area (hip joint prostheses) complicates the visualization of the pelvic venous plexuses. The procedure is performed with an empty bladder for reliable assessment of the diameter of the pelvic venous plexuses.

• MSCT (A06.12.055, computed tomography angiography of pelvic vessels) is recommended for patients with recurrent chronic pelvic pain after surgical or endovascular intervention on the gonadal veins in patients with PVCS [16,55,56,220].

LNC 4 LeC C

• Comments: MSCT allows for the detection of technical and diagnostic errors of the performed treatment (unresected/unembolized gonadal veins, additional gonadal vein trunks, compression stenosis of the LRV or left common iliac vein).

Magnetic resonance imaging (MRI)

• MRI (A05.30.004.001, magnetic resonance imaging of pelvic organs with intravenous contrast enhancement) is recommended as an additional non-invasive imaging method for pelvic varices when planning surgical or endovascular treatment for patients with PVCS in case of discordance between clinical and ultrasound findings [2,180,203].

LNC 4 LeC C

Comments: There are contrast-enhanced and non-contrast MRI modalities. These are minimally invasive and non-invasive imaging methods, respectively, which provide a comprehensive view of the topographical and anatomical features of the pelvic and retroperitoneal veins over a large extent. MRI allows for the assessment of surrounding organs and tissues due to its superior tissue contrast compared to MSCT. Because of high tissue contrast, MRI provides a reliable evaluation of pelvic organs (uterus, prostate gland) unlike MSCT. This method helps rule out other causes of pelvic pain (endometriosis, inflammatory changes in pelvic organs) [157,159,175,191,221-223]. MRI does not involve the use of ionizing radiation and iodine-containing radiocontrast agents, making it suitable for patients with iodine allergies and thyroid disorders [183,191,192,217]. Non-contrast MRI is used to examine patients with renal failure and pregnant women. Contrast-enhanced MRI cannot be used in patients with kidney disease and in pregnant women [116]. Currently, there are no clear guidelines on the procedure methodology. The quality of the study depends on the experience and knowledge of the radiologist, the technical characteristics of the scanner, and the protocols used [157,191,192,203,209,224]. Flow artifacts, patient preparation, and constitutional features significantly affect the quality of the study [141,175,183,191].

Nutcracker syndrome

• When describing MRI findings (A05.30.004.001, magnetic resonance imaging of pelvic organs with intravenous contrast enhancement) in patients with aortomesenteric compression of the LRV, it is recommended to indicate [45,166,200,227]:

- anatomical variations of the renal veins and their skeletotopy;

- ratio of the left renal vein diameter at the level of the superior mesenteric artery and proximal to this zone;

– the angle of origin of the SMA from the aorta;

- anatomical variations of the gonadic veins, indicating the number of trunks and variants of the gonadal-renal anastomosis location;

– anomalies of the IVC;

- presence/absence of thrombi in the renal, gonadal, and inferior vena cava;

- presence/absence of obliteration of these vessels;

- presence and severity of the collateral network.

LNC 5 LeC C

• MRI (A05.30.004.001, pelvic magnetic resonance imaging with intravenous contrast) is not recommended for assessing the efficacy of endovascular treatment for nutcracker syndrome, identifying the causes of recurrence, and evaluating stent patency [2,54].

LNC 5 LeC C

Comments: Vascular stents (167760 Stent for iliofemoral venous segment***) and embolization coils (Endovascular microcoils for embolization (323510 Vascular embolization coil outside the brain***)) can cause artifacts that preclude a reliable assessment of the stented vein lumen and the presence of incomplete vein lumen occlusion. When using vascular stents (167760 Stent for iliofemoral venous segment***) and embolization coils (Endovascular microcoils for embolization (323510 Vascular embolization coil outside the brain***)), stent patency and venous lumen obliteration can only be judged by indirect signs, such as the presence and intensity of collateral vein development and the contrast enhancement patterns of adjacent venous segments.

May-Thurner syndrome

• MRI (A05.30.004.001, pelvic magnetic resonance imaging with intravenous contrast) is recommended as an additional diagnostic method for iliac vein compression suspected on the basis of clinical symptoms and duplex ultrasound findings [193,209,221].

LNC 5 LeC C

Comments: MRI allows for the assessment of the level, extent, and cause (arteries, mass lesions) of common iliac vein compression stenosis. It should be borne in mind that MRI is a static method performed with the patient in the supine position, which affects the severity of compression to a greater extent than CT venography [159]. The respiratory phase and patient hydration also affect the transverse dimensions of the venous lumen at the compression level [180,207,215,218,224,227,228].

• MRI (A05.30.004.001, pelvic magnetic resonance imaging with intravenous contrast) is not recommended for assessing the hemodynamic significance of iliac vein compression stenosis [115,142,159,191,207,224,228,229].

LNC 5 LeC C

Comments: MRI cannot be a reliable method for assessing the venous lumen at the level of compression and the hemodynamic significance of iliac vein compression stenosis in the absence of signs of venous lumen obliteration. Visualization of the venous lumen depends on flow artifacts, patient preparation, technical characteristics of the scanner, and the scanning protocol [175,182,207]. The severity of compression depends on patient hydration, respiratory phase, and body position; accordingly, the degree of compression cannot be an indicator of its hemodynamic significance. The presence of an expanded collateral network allows one to suspect the hemodynamic significance of compression to some extent [124,159,175,180,183,213,215,229,230]. Early contrast enhancement of the internal iliac vein may be due to either May-Thurner syndrome or primary internal iliac vein valve incompetence. Dynamic MRI requires special technical, methodological, and software support.

• When describing an MRI (A05.30.004.001, pelvic magnetic resonance imaging with intravenous contrast) in female patients with May-Thurner syndrome, it is recommended to indicate [158,174,212,214,228]:

– the level and extent of compression;

– the variant anatomy of the iliac veins;

– the diameter of the iliac veins before and at the level of compression, depending on the respiratory phase;

- presence/absence of thrombi in the iliac veins, obliteration of the iliac vessels;

– the presence and prominence of the collateral network;

LNC 5 LeC C

• MRI (A05.30.004.001, pelvic magnetic resonance imaging with intravenous contrast) is not recommended for assessing the efficacy of endovascular treatment for May-Thurner syndrome [2,54,196,207,212].

LNC 5 LeC C

Comments: MRI does not allow for an adequate assessment of stented vein patency. The efficacy of the treatment and stent patency can only be judged by indirect signs such as a decrease in the diameters of the collateral network veins [196].

Pelvic venous congestion syndrome

• MRI (A05.30.004.001, pelvic magnetic resonance imaging with intravenous contrast) is recommended as an additional diagnostic method for pelvic varices verified by duplex ultrasound in patients scheduled for gonadal vein interventions, in case of a discrepancy between clinical and ultrasound findings [54,175,180,191,203,205,217,218,231].

LNC 5 LeC C

Comments: MRI makes it possible to assess the diameters of pelvic veins. There are studies on dynamic MRI that allow for the evaluation of reflux in the internal iliac vein and gonadal veins, but it must be remembered that reflux may not only be a consequence of compression, but also a manifestation of primary valve incompetence [225,226,232]. MRI can be used to rule out concurrent pathology and select patients for additional examination methods (renography, ovariography, pelvic phlebography, IVUS). Unlike MSCT, MRI, especially non-contrast, does not allow a reliable assessment of the patency of the pelvic venous plexuses [191]. Pronounced flow artifacts, as well as dependence on patient preparation, complicate the visualization of pelvic venous plexuses. Contrast-enhanced MRI is preferable to non-contrast examination for assessing the condition of internal iliac vein tributaries [231].

• When describing an MRI (A05.30.004.001, pelvic magnetic resonance imaging with intravenous contrast) in patients with pelvic venous congestion syndrome, it is recommended to [54,175,203,205]:

- indicate the diameter of pelvic veins (gonadal, parametrial, arcuate, uterovaginal);

- note pathological changes in the organs and tissues of the examined area (if detected);

LNC 5 LeC C

Radiopaque phlebography

Radiopaque phlebography (ROPF / A06.12.023, renal vein phlebography; A06.12.025, pelvic phlebography) serves as the "gold standard" for diagnosing pelvic varices and pelvic venous congestion syndrome, and includesiliacavography, renophlebography, selective ovariography, and multi-positional pelvic phlebography [2,4,53,55,79,124,218].

The objectives of radiopaque phlebography are [24,54,64,65,74,82,91,93,131]:

• assessment of the left renal vein status (patency, anatomical variants of the left renal vein, compression stenosis of the left renal vein and its severity, presence of varices in the renal hilum and perirenal tissue; in patients with suspected nutcracker syndrome, measurement of pressure in the left renal vein and inferior vena cava with calculation of the renocaval pressure gradient [RCG]);

• precise determination of gonadal vein anatomy (location of ovarian-renal and ovarian-caval anastomoses, diameter, presence and localization of large tributaries, type of gonadal vein structure – single-trunk, double-trunk, multi-trunk);

• detection of blood flow collateralization ("overflow" of contrast agent to the contralateral side via parametrial and uterine veins, visualization of the left iliolumbar vein);

• assessment of the iliac veins status (patency, diameters, compression stenosis of the left/right common iliac vein and its percentage degree, presence of contrast agent reflux into the internal iliac veins and their tributaries).

• Visualization and mapping of pelvrineal reflux, indicating the refluxing tributaries of the internal iliac vein.

Depending on the objectives set for phlebography, its various modifications and combinations are used.

• To determine the indications for mechanical or chemical embolization of the gonadal veins (EGV) in patients with pelvic venous congestion syndrome and gonadal vein reflux, it is recommended to perform selective ovariography (A06.12.025 pelvic phlebography) [1,2,53,54,63,73,233-235].

LNC 4 LeC C

Comments: for phlebography, it is advisable to use the cubital approach as the least invasive, or the femoral or jugular approaches with ultrasound guidance [54-56,64,99,122]. The femoral approach is accompanied by the formation of hematomas in 6% of cases [236].

• To detect compression stenoses of the left renal vein and left common iliac vein, it is recommended to use renophlebography (A06.12.023, renal vein phlebography) and multi-positional pelvic phlebography (A06.12.025, pelvic phlebography) [16,53,113,124,131,237,238].

Level of Evidence (LE) 4, Grade of Recommendation (GR) C

Comments: the hemodynamic significance of left renal vein stenosis and the need for surgical intervention on this vessel are determined based on the values of the renocaval pressure gradient calculated using phlebotanometry [9,24,45,53,99,104,150,167,244,247,249]. To determine the degree of left common iliac vein stenosis, pelvic phlebography must be performed in the anteroposterior, posteroanterior, and oblique lateral projections [181,246,254,256,260].

• Radiopaque phlebography (A06.12.025, pelvic phlebography) is recommended in case of discrepancies between clinical and ultrasound findings, or the results of MSCT or MRI [75, 239-241].

LNC 4 LeC C

Comments: in a number of cases, there is a discrepancy between the clinical presentation of the disease and the results of instrumental examination of patients [56,62,242]. In such cases, phlebography is used as a reference diagnostic method.

• Phlebography (A06.12.025, pelvic phlebography) is recommended to be performed with the patient in the supine position, in the reverse Trendelenburg position, with the mandatory use of provocative maneuvers [2,21,53,54,124].

Level of Evidence (LoE) 5, Grade of Recommendation (GoR) C

• An increase in pelvic vein diameter of more than 5 mm during phlebography (A06.12.025, pelvic phlebography) is recommended to be considered as their varicose transformation [24,54,83].

Level of Reliability of Evidence 5, Level of Recommendation C

• X-ray phlebographic signs of pelvic congestion syndrome (PCS) are recommended to be considered [24,53,54,56,226,243]:

– contrast medium reflux into the left and/or right gonadal veins up to the pampiniform plexus;

– “overflow” of the contrast medium via the parametrial and uterine veins to the contralateral side;

– pooling of the contrast medium in the pelvic venous plexuses;

– contrast medium reflux into the trunk and tributaries of the internal iliac veins.

LNC 5 LeC C

Comments: only a combination of several of the above signs can be considered as the phlebographic pattern of PCS. The absence of contrast medium reflux through the gonadal veins is not a sign indicating the absence of PCS, since reflux through the parametrial and uterine veins, and pelvic venous plexuses with contrast pooling in these veins can cause the development of PCS [1,2,64,72-74].

• Left-sided renophlebography with phlebo-manometry (A06.12.023, renal vein phlebography) is recommended to detect compressive stenosis of the left renal vein (LRV) and determine its hemodynamic significance based on reno-caval pressure gradient (RCG) values [131,237,244,245].

LNC 4 LeC C

Comments: renal vein phlebography serves as the only method that allows phlebomanometry with a quantitative assessment of renal venous pressure. RCG indicators indicate a hemodynamically significant compressive stenosis of the LRV or its absence [10].

• Phlebographic signs of nutcracker syndrome (NS) are recommended to be considered as follows: a decrease in the anteroposterior diameter of the meso-aortic segment of the LRV, contrast medium pooling in the pre-stenotic section of the LRV, opacification of perirenal and/or periureteral venous collaterals, and contrast medium reflux into the left suprarenal and gonadal veins [53,54,166,245,246].

LNC 5 LeC C

• An RCG of no more than 1 mm Hg is recommended to be considered a normal value [10,53,96,247].

LNC 5 LeC C

• RCG values > 3 mm Hg are recommended to be considered as a sign of hemodynamically significant LRV stenosis [9,10,24,53,131,245].

LNC 5 LeC C

• To assess the hemodynamic significance of compressive LRV stenosis in the presence of pronounced collaterals in the left kidney and ureter region, it is not recommended to rely solely on RCG [9,10,238,247-249].

LNC 5 LeC C

Comments: the formation of collateral venous outflow pathways from the left kidney indicates pronounced compressive stenosis of the LRV [3,10,131]. It has been proven that in the case of detecting powerful bypass pathways for LRV narrowing, the pressure in this vessel may not exceed normal values. At the same time, a combination of varicose veins of the hilum and lower pole of the left kidney and the recording of a reno-caval gradient exceeding 3 mm Hg is possible, which indicates severe LRV obstruction. Several authors indicate the significance of clinical manifestations of NS: the presence of hematuria, left flank pain in combination with a low RCG should be considered as NS, which is an indication for transposition of the LRV or the left gonadal vein [52,53].

• Patients with May-Thurner syndrome (MTS) are recommended to undergo multi-positional pelvic phlebography (A06.12.025, pelvic phlebography) [24,66,67,250,251].

Level of Evidence (LE) 3, Grade of Recommendation (GR) B

Comments: for an accurate assessment of iliac vein diameters and calculation of the degree of left common iliac vein (LCIV) stenosis, it is necessary to perform pelvic phlebography in several positions: anterior, posterior, left and right oblique lateral. This makes it possible to determine the degree of narrowing of the left LCIV as accurately as possible in patients with MTS. In detecting LCIV stenosis > 70%, the sensitivity of single-plane standard anteroposterior projection does not exceed 45%.

• Phlebographic signs of MTS are recommended to be considered [62,246,251-253]:

– narrowing of the anteroposterior diameter of the left LCIV in the area of its intersection with the right common iliac artery > 50%;

– contrast medium reflux into the ipsilateral internal iliac vein;

– “overflow” of the contrast medium to the contralateral side;

– visualization of dilated left iliolumbar vein and/or left gonadal vein.

LNC 5 LeC C

Comments: for phlebographic verification of MTS, detecting only the narrowing of the left LCIV lumen is not sufficient. The narrowing may be significant, but blood flow in the LCIV does not undergo significant changes, i.e., vein compression does not cause its obstruction, which explains the absence of clinical manifestations of the disease [111,112]. Therefore, to determine significant stenosis of the left LCIV, a combination of several phlebographic signs of MTS is required.

• Narrowing of the left LCIV > 50% according to pelvic phlebography (A06.12.025, pelvic phlebography) is not recommended to be considered the sole criterion for the hemodynamic significance of left LCIV stenosis [111,112].

LNC 5 LeC C

Comments: currently, the criterion of 50% narrowing of the left LCIV is being questioned; it has been proven that in a number of cases, LCIV narrowing > 50% does not lead to significant changes in pelvic phlebohemodynamics and the emergence of clinical manifestations of MTS. Conversely, left LCIV stenosis < 50% in combination with other phlebographic signs of MTS is accompanied by significant disorders of venous outflow from the pelvic organs and the formation of PCS.

• The “bull's eye sign” in combination with the contouring of the balloon catheter in the area of LCIV stenosis is recommended as one of the reliable phlebographic signs of MTS [62,246,254,255].

LNC 5 LeC C

Comments: the “bull's eye sign” characterizes indirect signs of compressive iliac vein stenosis: a rim along the edges of the common iliac vein with low opacification of its center in the projection of the spur [255].

Intravascular ultrasound

Intravascular ultrasound of the vascular wall (A04.12.004), along with RCG, serves as the reference method for diagnosing MTS. Intravenous ultrasound is performed after pelvic phlebography to more accurately determine the degree of stenosis. At the same time, skepticism towards 50% vessel narrowing as the main criterion for its hemodynamic significance may probably neutralize all the advantages of IVUS. Nevertheless, the high sensitivity of the method (up to 90%) provides greater accuracy in detecting non-thrombotic iliac vein stenoses [239,240,250,256-260].

Factors limiting IVUS include acoustic shadowing from the calcified wall of the adjacent artery and stent structure, rotational distortion artifacts occurring in tortuous vessels, and multiple circular echoes from reverberating ultrasound beams [180,246,251,258].

• IVUS (A04.12.004) is recommended to be used for accurate diagnosis of the degree of compressive stenoses of the LRV and LCIV [9,250,258,259,261].

Level of Evidence (LE) 3, Grade of Recommendation (GR) C

Comments: IVUS allows for better visualization of the intra-luminal state of the vessel, calculation of the area of the stenosed vessel segment, differentiation of post-thrombotic and non-thrombotic venous obstructions, and assessment of venous wall thickness and neointimal hyperplasia.

• IVUS (Intravascular ultrasound of the vascular wall A04.12.004) is recommended to be considered the optimal diagnostic tool for direct intraluminal measurement of the lumen diameter and cross-sectional area of the studied vein and assessment of the degree of its stenosis [239-241,255,261].

Level of Evidence (LE) 3, Grade of Recommendation (GR) C

2.5 Other Procedures

The use of other diagnostic examinations is not provided.

3. Treatment, including drug and non-drug therapies, diet therapy, and pain management

3.1 General Provisions and Treatment Tactics for Pelvic Varicose Veins

The variability of clinical manifestations of pelvic varicose veins (PVV), the deep anatomical location of the pelvic veins, and the presence of asymptomatic forms of the disease determine the specifics of PVV treatment. Pelvic vein dilation and reflux within them are not absolute indications for conservative or surgical treatment of these patients. The clinical picture plays a paramount role in determining the treatment method for PVV. The second factor influencing treatment tactics is the prevalence of PVV, the involvement of various pelvic veins in the pathological process, and the presence of compressive stenoses of the LRV and left LCIV and their hemodynamic significance.

3.1.1 Indications for Conservative Treatment

• Conservative treatment is recommended for symptomatic patients with isolated dilation of pelvic venous plexuses (parametrial, uterine, arcuate veins) and blood reflux through them [81,92,262-265].

LNC 4 LeC C

Comments: the prevalence of lesions and valvular insufficiency of visceral pelvic veins are detected using transvaginal and transabdominal duplex ultrasound. Isolated dilation and reflux in the parametrial and uterine veins are diagnosed in 60-70% of patients [1,3,37]. Varicose transformation of these vessels does not imply their surgical removal or endovascular occlusion. Hysterectomy, subtotal hysterectomy, and oophorectomy are considered unacceptable methods for treating pelvic varices [266].

• Conservative treatment is recommended for patients with symptomatic pelvic varicose veins [1,2,4,24,54,77,126-136,267-272].

LNC 5 LeC C

Comments: currently, medical or compression treatment is used only if the patient has symptoms of pelvic varices. There are no studies proving the necessity of any conservative measures among patients with a latent, asymptomatic form of the disease.

3.1.2 Indications for Surgical and Endovascular Treatment

• Surgical or endovascular intervention on the gonadal veins is recommended for patients with symptoms of pelvic congestion syndrome, dilation of the gonadal, parametrial, uterine, and arcuate veins, and reflux through them without hemodynamically significant compression stenoses of the left renal vein and left common iliac vein [52-54,79,81,171,234,235,262,265,266,275-279, 349].

LNC 5 LeC C

Comments: Blood reflux through the gonadal veins serves as the leading factor in the development of symptomatic pelvic varices and pelvic congestion syndrome. Numerous studies have proven that the reduction of blood flow through the gonadal veins leads to a decrease in blood pooling in the pelvic venous plexuses, restoration of the normal functioning of the valvular apparatus of the parametrial and uterine veins, acceleration of venous outflow from the pelvic organs, and a significant reduction or complete disappearance of disease symptoms, primarily pelvic pain [81,171,262,265,266,280,281,349].

• Eliminating reflux in the gonadal veins in female patients with pelvic varices is recommended using resection (A16.28.045 Ligation and transection of the testicular vein) or embolization (A16.21.049 Ovarian vein embolization) of these vessels [81,171,234,235,262,265,266,275].

LNC 4 LeC C

• Perineal venectomy is recommended for patients with dilation of vulvar, perineal, gluteal veins, and veins of the posteromedial surface of the thighs with reflux through them [84,287,289].

LNC 4 LeC C

Comments: the appearance of varicose veins on the external genitalia, perineum, and gluteal region is due to pelvi-perineal reflux, which occurs in the vast majority of patients (90-95%) during pregnancy [66,282-284]. The persistence of pelvi-perineal reflux is questionable, as proven by a number of studies [67,119,285-287]. In addition, even in the presence of retrograde blood flow from the internal pelvic veins to the superficial veins of the perineum, buttocks, and lower extremities, the removal of varicose veins in these areas is accompanied by obvious hemodynamic and clinical effects and rare recurrences, no more than 10% [288-290].

• Surgical intervention on the left renal vein is recommended for patients with compression stenosis of this vessel, the presence of clinical and laboratory symptoms and signs of nutcracker phenomenon, and an increase in renocaval pressure gradient > 3 mm Hg [9,124,200,204,250,291,292].

LNC 5 LeC C

Comments: nutcracker phenomenon is accompanied by a significant increase in pressure in the left renal vein, leading to impaired renal function manifested by micro- or macrohematuria and proteinuria [293,294]. The developing collateral blood flow leads to varicose transformation of the perirenal venous plexuses and the left gonadal vein. Surgical intervention in such circumstances aims to reduce renal venous hypertension [10,295]. Left renal vein transposition is a traumatic surgery during which a new renocaval anastomosis is formed lower than the native one. The disadvantage of transposition is the technical difficulty in forming the anastomosis, as the distance from the renal orifice to the inferior vena cava increases, while the segments of the left renal vein, conversely, shorten. In addition, 30% of patients develop stenosis of the newly formed anastomosis, requiring re-intervention or endovascular treatment [9,10]. Another, less traumatic method of surgical treatment is shunting procedures or left gonadal vein transposition. They involve creating an anastomosis between the left gonadal vein and the left external iliac or inferior vena cava [245,296,297].

3.2 Compression Treatment

• For female patients with symptomatic pelvic varicose veins, the use of class II compression shorts is recommended to relieve chronic pelvic pain [1,264,298,299].

LNC 4 LeC C

Comments: currently, there are no large randomized trials on the efficacy and safety of compression treatment for pelvic varices. Moreover, compression garments that affect the pelvic and perineal regions are not freely available (pharmacies, compression knitwear salons). To conduct compression treatment using knitwear, products must be ordered from manufacturers for each specific patient. There are problems in creating graduated compression corresponding to the appropriate compression class (I or II). Class II compression shorts used in the single non-randomized comparative study on this issue [298,299] were originally intended for use after body contouring surgeries (liposuction, abdominoplasty). Therefore, it is necessary to set tasks for manufacturers of compression knitwear to create the required special products to affect venous outflow from the pelvic organs in pelvic varices and varicose veins of the pelvis.

• In the treatment of patients with combined pelvic varicose veins and lower extremity varicose veins, the combined use of class II compression shorts and class II compression stockings is recommended [264,298,299].

LNC 4 LeC C

Comments: among patients with pelvic varicose veins, 30-50% have a combination of the disease with lower extremity varicose veins [58,122,300,301], which is why the use of compression stockings in this category of patients is well-founded.

LNC 4 LeC C

Comments: The use of compression stockings does not affect the clinical manifestations of pelvic varicose veins and venous outflow from the pelvic organs.

3.3 Medical treatment

• Pharmacotherapy is recommended for patients with symptomatic pelvic varices [2,4,70,263,267-270].

LNC 5 LeC C

Comments: medical treatment with bioflavonoids is most effective in female patients with isolated dilation and reflux in the pelvic venous plexuses (parametrial, uterine veins, uterovesical, and vaginal venous plexuses).

3.3.1 Efficacy of Various Medicinal Products in Relieving Symptoms of Pelvic Varicose Veins

Bioflavonoids (C05CA)

Considering the unity of the mechanisms of development of pelvic varicose veins and lower extremity varicose veins, treatment with bioflavonoids serves as a pathogenetic method of drug therapy for the disease [269,270,272]. The most studied group of agents with proven efficacy regarding the symptoms of pelvic varicose veins is bioflavonoids [92,264,267,268].

• The prescription of bioflavonoids is recommended for patients with symptomatic pelvic varicose veins and pelvic congestion syndrome [4,92,264-272].

Level of Evidence (LE) 3, Grade of Recommendation (GR) C

Comments: numerous studies, including two randomized ones, have proven the efficacy and safety of using bioflavonoids for the treatment of symptomatic forms of pelvic varicose veins and pelvic congestion syndrome [2,4,70,263,267-270,272]. The authors report a reduction or complete relief of pelvic pain in 70-90% of patients [92,264,267-269,272-274], with the number of adverse events and side effects not exceeding 6%.

• The intake of bioflavonoids by pregnant women can be recommended only in the third trimester of pregnancy [271].

Level of Evidence (LE) 2, Grade of Recommendation (GR) A

Comments: currently, there is 1 randomized study on the use of bioflavonoids in pregnant women to prevent the progression of pelvic varices [271]. Bioflavonoids should be prescribed with caution for the treatment or prevention of pelvic varices in pregnant women. Under conditions of increased hemodynamic load on the pelvic veins and a significant increase in plasma progesterone concentration, the risks of using bioflavonoids may outweigh the benefits. Further research is needed to determine the appropriateness of using bioflavonoids as a treatment in pregnant women.

• The prescription of bioflavonoids is not recommended for patients with the asymptomatic form of pelvic varicose veins [267-269,302].

Level of Evidence (LE) 5, Grade of Recommendation (GR) C

Comments: currently, there are no studies investigating the use of bioflavonoids among patients with a latent, asymptomatic form of the disease. Therefore, there is no basis to use bioflavonoids for treating the asymptomatic form of pelvic varicose veins.

Nonsteroidal anti-inflammatory and antirheumatic drugs

• In case of severe pain syndrome, short-term prescription of nonsteroidal anti-inflammatory and antirheumatic drugs is recommended [54,77,272,303].

Level of Evidence (LE) 3, Grade of Recommendation (GR) C

Comments: non-steroidal anti-inflammatory and antirheumatic drugs may only be used as symptomatic therapy. The optimal route of administration for non-steroidal anti-inflammatory and antirheumatic drugs is via rectal and vaginal suppositories [303].

Hormones and related agents

The advisability of using hormones and related agents in the treatment of pelvic congestion syndrome is considered highly debatable. The analgesic effect of hormones and related agents is achieved by suppressing ovarian function with reduced estrogen production, inducing a medical menopause that leads to impaired reproductive function in women, thereby depriving them of childbearing potential [102, 264]. Side effects and adverse events of hormonal therapy significantly impact patients' quality of life and include weight gain, mood lability, hot flushes, sensation of warmth, osteoporosis, and venous thromboembolic complications [102, 304, 305].

• The use of hormones and related agents is not recommended for the relief of chronic pelvic pain caused by pelvic varices [264, 267].

LNC 5 LeC C

Comments: #medroxyprogesterone** (L02AB02, antineoplastic and endocrine therapy agents, hormones and related agents, progestogens; off-label drug use, not approved by state regulatory authorities, not mentioned in the package leaflet. Regimen: 50 mg/day orally once daily for 4 months [304]) significantly reduced pain levels compared to placebo, but a rapid return of pain syndrome was noted immediately after drug withdrawal. The use of MP combined with psychotherapy led to the relief of chronic pelvic pain only 9 months after treatment completion. Treatment with MPA was accompanied by menstrual irregularities: amenorrhea in 58% of patients, hypomenorrhea in 40%, and moderately heavy bleeding in 2%. MPA use was accompanied by a high incidence of adverse effects, such as weight gain and abdominal bloating. In a multicenter study by Walton et al., no differences in the efficacy of chronic pelvic pain relief were found between patients using MP and placebo [306].

The advantage of #goserelin** (L02AE03, antineoplastic and endocrine therapy agents, hormones and related agents, gonadotropin-releasing hormone analogues; off-label drug use, not approved by state regulatory authorities, not mentioned in the package leaflet. Regimen: 3.6 mg subcutaneously into the abdominal wall every 28 days for 6 months [102]) over MP in relieving pelvic pain has been proven. The study did not provide data on the frequency and severity of adverse events.

The efficacy of #etonogestrel (G03AC08, sex hormones and modulators of the genital system, hormonal contraceptives for systemic use, progestogens; off-label drug use, not approved by state regulatory authorities, not mentioned in the package leaflet. Regimen: forearm subcutaneous implant once between the first and fifth day of the menstrual cycle [305]) in relieving chronic pelvic pain has been proven. The study did not provide data on the frequency and severity of adverse events, except for a mention of hypomenorrhea.

The aforementioned studies have been criticized because hormonal treatment is an effective treatment for other causes of chronic pelvic pain, which the authors do not report, but this may account for the positive results of hormone therapy [24, 54].

In the studies presented above, a reduction or complete relief of chronic pelvic pain was observed in 60–90% of patients [102, 304–306]. At the same time, the authors did not emphasize to readers that the use of hormone replacement therapy leads to medical menopause and that young and middle-aged patients lost their fertility. In addition, the therapeutic effect (absence of pelvic pain) persisted for only a short period after discontinuation of treatment with hormones and related agents (from 1 to 3 months), after which the pain recurred.

• Hormone therapy is not recommended as a pathogenetic treatment method for pelvic congestion syndrome [1, 2, 4, 24, 54, 264, 267].

Level of Evidence (LE) 3, Grade of Recommendation (GR) C

Comments: the positive effect of taking hormones and related agents, despite the reduction in pelvic pain severity, is offset by a significant number of complications and adverse effects, the short duration of the therapeutic effect, and impairment of women's reproductive function [264, 267]. This necessitates the exclusion of this type of treatment from the list of possible therapeutic interventions in patients with pelvic congestion syndrome.

Psychopharmacological agents

Patients with chronic pain syndrome associated with pelvic varices often exhibit signs of anxiety, hypochondria, and depression, which provides a rationale for the use of psychopharmacological agents. Furthermore, the use of psychopharmacological agents is accompanied by a reduction in the severity of pelvic pain [309–313].

• To reduce the severity of chronic pelvic pain, #citalopram (N06AB04, psychoanaleptics, antidepressants, selective serotonin reuptake inhibitors; off-label drug use, not approved by state regulatory authorities, not mentioned in the package leaflet. Regimen: 20–60 mg/day once daily for 3 months [310]) is recommended.

LNC 4 LeC C

• To determine the advisability of prescribing psychopharmacological agents for the relief of chronic pelvic pain, an individual multimodal approach aimed at eliminating central and peripheral pain generators, as well as psychosomatic disorders, is recommended [313, 314].

LNC 5 LeC C

Comment. The prescription of psychopharmacological agents must be coordinated with a psychiatrist.

3.3.2 Regimen and dosing of bioflavonoids (C05CA53, angioprotectors, capillary-stabilizing agents, bioflavonoids)

In the package leaflets of bioflavonoids registered in the Russian Federation, pelvic venous disorders and pelvic congestion syndrome are not listed as indications for use. At the same time, existing international and domestic experience with bioflavonoids and the common mechanism of development of pelvic and lower extremity varicosities allow bioflavonoids to be successfully used in the treatment of pelvic congestion syndrome [2, 4, 70, 93, 267, 269, 272, 303]. The bioflavonoid dosing regimen should follow the manufacturer's recommendations regarding chronic venous diseases specified in the package leaflets of specific medications [315].

3.4 Sclerotherapy Treatment

Phlebosclerotherapy as a standalone treatment method is used in patients with pelvic pain syndrome, vulvar varices, perineal varices, gluteal varices, and isolated varicosities of the posteromedial surface of the thighs without great saphenous vein valve incompetence [53, 54, 79, 117, 118, 285–289]. The administration of vein-sclerosing agents via local injections into the gonadal veins and tributaries of the internal iliac veins is classified as treatment for pelvic congestion syndrome, and these techniques will be discussed in the relevant section.

3.4.1 Indications for Sclerotherapy

• Phlebosclerotherapy is recommended for patients with lower extremity varicosities and varicose veins originating from pelvic veins, i.e., caused by pelvic pain syndrome (vulvar, perineal, gluteal varices, and varicosities of the posteromedial surface of the thighs) [53, 54, 79, 117, 118, 289].

Level of Evidence (LE) 3, Grade of Recommendation (GR) B

Comments: to date, guidelines and scientific studies do not provide specific instructions on when to use sclerobliteration of varicose veins originating from pelvic veins versus surgical removal (phlebectomy) of these veins. However, the literature contains a sufficient number of works by various authors indicating the safety and efficacy of this therapeutic method in correcting pelvic pain syndrome [66, 67, 76, 119, 316–320].

Therefore, it is advisable to adhere to the following principle: if duplex ultrasound data show that the vein diameter does not exceed 5 mm, sclerotherapy may be performed. Otherwise, the optimal treatment method is phlebectomy in the perineum or on the lower extremity [288, 289]. There are also no specific recommendations regarding the formulation of the vein-sclerosing agent for local injections to eliminate vulvar, perineal, gluteal varicose veins, and varicosities of the posteromedial surface of the thighs. Consequently, both liquid and foam formulations of the drug can be used when performing sclerobliteration.

3.4.2 Contraindications for Sclerotherapy

• Phlebosclerotherapy is not recommended for patients with lower extremity varicosities and pregnancy, in cases of intolerance to the vein-sclerosing agent for local injections, or in the presence of superficial thrombophlebitis of vulvar veins, superficial veins of the lower extremities, or deep vein thrombosis of the lower extremities [317–319].

Level of Evidence (LE) 3, Grade of Recommendation (GR) C

Comments: contraindications to sclerotherapy for vulvar and perineal varices are similar to those for lower extremity varicose veins [81]. Despite the absence of a direct anatomical connection between perineal and deep lower extremity veins or iliac veins, foam forms of sclerosing agents for local injections are contraindicated in patients with a patent foramen ovale confirmed by instrumental diagnostic methods [321].

3.4.3 Sclerotherapy Techniques

• To perform sclerobliteration of vulvar and perineal varices, it is recommended to use medications from the group of sclerosing agents for local injections (C05BB sclerosing agents for local injections) (lauromacrogol-400 [C05BB02, sclerosing agent]; sodium tetradecyl sulfate [C05BB04, sclerosing agent]) [319, 320, 322].

Level of Evidence (LE) 3, Grade of Recommendation (GR) B

Comments: there is no fundamental difference in the choice of drugs for sclerotherapy of vulvar varicose veins or lower extremity veins. Morphofunctional changes in vulvar and perineal varices are identical to those in lower extremity varicose veins and do not require the use of any special technologies or sclerosing agents for local injections.

• Drugs from the group of sclerosing agents for local injections (C05BB sclerosing agents for local injections) are recommended to be used in the form of a solution or foam for sclerotherapy in patients with vulvar and perineal varices [322].

Level of Evidence (LE) 3, Grade of Recommendation (GR) B

Comments: there are no significant differences between sclerobliteration of vulvar and perineal varices using liquid or foam forms of sclerosing agents for local injections [322].

• After completing the sclerobliteration session for vulvar and perineal varices, manual compression of the sclerotherapy zone is recommended for 3–5 minutes [288, 289, 317, 320].

Level of Evidence (LE) 3, Grade of Recommendation (GR) B

Comments: there are no special garments for applying compression to the perineal region. Therefore, brief manual compression of the sclerotherapy site is sufficient. In cases of sclerobliteration of lower extremity varicose veins originating from pelvic veins, standard compression hosiery is used [324].

3.5 Surgical treatment

The primary goals of surgical intervention in patients with pelvic congestion syndrome are the relief of clinical symptoms and the normalization of venous outflow from the pelvic organs [4, 54, 81, 262]. First and foremost, the surgery aims to eliminate pathological reflux in the gonadal veins (GV). Gonadal vein surgery is recognized as the most effective treatment method for pelvic congestion syndrome [236, 281].

3.5.1 Surgical Interventions on the Gonadal Veins

• Gonadal vein resection (GVR) is recommended as an effective and safe treatment method for patients with pelvic congestion syndrome, aimed at eliminating reflux in the pelvic veins [4, 53, 79, 81, 84, 236, 242, 262, 280, 281].

LNC 4 LeC C

Comments: GVR is performed via open extraperitoneal, transperitoneal laparoscopic, and retroperitoneal endoscopic approaches. The essence of the surgery is the elimination of reflux in the gonadal vein, which leads to a significant reduction in venous congestion of the pelvic organs [281, 326-330]. After the elimination of reflux in the gonadal veins, a decrease in the diameters of parametrial, uterine, and arcuate veins, as well as the restoration of the function of their valve apparatus, is invariably observed. Regardless of the access type to the gonadal veins, the procedure consists of mobilizing and resecting at least 10–12 cm of the vessel. This not only ensures the elimination of gonadal vein reflux but also serves as an effective method for minimizing disease recurrence [171, 236, 281]. Complete disappearance or significant reduction of pelvic congestion and other disease symptoms was noted in 94–100% of patients with pelvic congestion syndrome [236, 281]. A negative aspect of these surgeries is the necessity of general anesthesia [236]. Perioperative complications were noted in no more than 10–12% of patients [171, 281]. Recurrences of pelvic congestion syndrome were noted in 6% of patients. Appendix A3.1 presents a comparative analysis of the results of resection versus embolization of gonadal veins in the treatment of pelvic congestion syndrome, which indicates the absence of significant advantages of either technique in relieving pelvic venous pain.

• Endoscopic GVR is recommended as the preferred surgical treatment method for patients with pelvic congestion syndrome [4, 329, 330].

LNC 4 LeC C

Comments: the endoscopic GVR method is characterized by lesser invasiveness and high aesthetic outcomes, with an almost complete absence of long-term disease recurrence during follow-up [4, 330]. Transperitoneal endoscopic GVR is advisable in cases of bilateral gonadal vein dilation and reflux [327, 333, 334]. Retroperitoneal GVR serves as the optimal treatment method for unilateral gonadal vein lesions [329, 330]. This is due to the technical features of the retroperitoneal approach: positioning the patient on the left/right side in a 30° Trendelenburg position, and placing trocars in the left or right lumbar region.

• Open retroperitoneal gonadal vein resection is recommended in cases of gonadal vein dilation exceeding 10 mm, impossibility of performing endoscopic gonadal vein resection, or gonadal vein embolization in patients with pelvic congestion syndrome [4,53,262,281,329,330,333,334].

LNC 4 LeC C

Comments: open retroperitoneal intervention on the gonadal vein involves making a 5–7 cm skin incision in the left and/or right iliac regions and sequential access to the retroperitoneal space [262,281,335]. This leads to pain syndrome in the immediate postoperative period. This aspect is perhaps the only negative quality of the surgery compared to the retroperitoneal endoscopic technique [329]. At the same time, the efficacy of open surgery in relieving symptom manifestations is 84–95%, and the aesthetic result is characterized by patients as good [79,280,281].

• Gonadal vein resection is recommended as a universal treatment method for patients with pelvic congestion syndrome [79,81,84,236,242,262,280,281,326-330,333-335].

LNC 4 LeC C

Comments: this treatment method can be used regardless of the anatomical features of the gonadal veins (multi-trunk structure, dilation > 10 mm, atypical gonado-renal or gonado-caval junction, right/left ovarian vein syndrome), the patient's constitutional features, and the presence of allergies to contrast media and nickel.

• Transperitoneal endoscopic gonadal vein resection is recommended when performing simultaneous surgeries on the veins and pelvic organs [79,262,281,333-335].

LNC 4 LeC C

Comments: in a number of cases, patients with pelvic congestion syndrome require combined surgical interventions on the veins and pelvic organs, for example, when a combination of pelvic congestion syndrome with gonadal vein reflux and uterine fibroids or external genital endometriosis is detected. In such patients, it is advisable to use a laparoscopic treatment method, where the first stage is intervention on the gonadal vein, and the second is surgery on the pelvic organs (subtotal hysterectomy, electrocoagulation of endometriosis lesions) [334,335].

• It is recommended to consider the disappearance of reflux in the gonadal, parametrial, and uterine veins as an indicator of the efficacy of surgical treatment for pelvic congestion syndrome [1-4,52-54,94].

Level of Evidence (LE) 3, Grade of Recommendation (GR) B

3.5.2 Surgical Interventions on the Vulvar Veins

• Phlebectomy (A16.12.012, ligation and exposure of varicose veins) in the perineum is recommended as an effective and safe method for eliminating varicose veins of the vulva and perineum [66,119,289,290,318].

Level of Evidence (LE) 3, Grade of Recommendation (GR) B

Comments: several comparative cohort studies have proven the efficacy and safety of local perineal phlebectomy in relieving clinical manifestations of pelvic venous disorders (vulvar, perineal, gluteal varicosities) [84,289,290,336]. These data indicate the possibility of eliminating pelvic venous disorders without embolization of internal iliac vein tributaries. There are no studies available in the medical literature comparing the results of embolization of internal iliac vein tributaries or trunk with perineal phlebectomy. At the same time, a number of authors indicate the persistence of perineal and vulvar varicose veins after internal iliac vein tributary embolization in 50% of patients [48].

• Phlebectomy (A16.12.012, ligation and exposure of varicose veins) on the labia majora is recommended to be performed through small (up to 1 cm) incisions [66,79,289,282,336].

Level of Evidence (LE) 3, Grade of Recommendation (GR) B

Comments: the anatomical features of the labia majora necessitate surgical intervention through incisions. They are formed by skin folds containing subcutaneous adipose tissue and a large number of sebaceous and sweat glands. In addition, the structure of the labia majora contains fascial formations that do not allow adequate isolation and grasping of the vein using a vein stripper. As a result, active traction with a vein stripper can lead to vein tearing and the formation of extensive perineal hematomas, since detecting a bleeding vein in the tissues through a 2 mm puncture would be problematic, and applying a compression bandage in this area is impossible.

• When varicose veins are localized in the labia minora, resection of the labia minora (A16.20.067, resection of labia minora) together with the varicose veins is recommended [66,289].

LNC 4 LeC C

Comments: the appearance of varicose veins in the labia minora is always accompanied by their deformation and hypertrophy, which is why resection of the labia minora with varicose veins en bloc should be performed, followed by marginal plasty of the labia minora.

• Phlebectomy (A16.12.012, ligation and exposure of varicose veins) outside the external genitalia is recommended using the miniphlebectomy technique [66, 289].

Level of Evidence (LE) 3, Grade of Recommendation (GR) B

• The absence of varicose veins in the perineum in patients with vulvar/perineal varicosities is recommended as an indicator of the effectiveness of perineal phlebectomy [51, 66, 72, 76, 318].

Level of Evidence (LE) 3, Grade of Recommendation (GR) B

3.5.3 Surgical Interventions for Left-Sided Renal Venous Hypertension

• Reconstructive surgery is recommended for aortomesenteric or aortorenal compression of the left renal vein, diagnosed by instrumental imaging methods, in the presence of venous hypertension manifested as specific clinical symptoms, laboratory abnormalities, and an increased cavarenal gradient of venous pressure (CRG > 3 mm Hg) [295, 337, 338].

LNC 4 LeC C

Comments: to date, the values of the renocaval gradient (RCG), which determines the severity of venous hypertension in the left renal vein (LRV), have not been definitively established, but most authors indicate an RCG value greater than 3 as a criterion for severe left-sided renal venous hypertension [337-341]. At the same time, in all these studies, the clinical manifestations of PCS serve as an obligatory criterion for determining the indications for LRV surgery. Based on literature data, it appears that it is precisely the symptoms and signs of LRV compression stenosis that serve as the most important indicator, while the magnitude of the RCG is an auxiliary characteristic. In the presence of pain syndrome, hematuria, and proteinuria, the RCG may be < 3 mm Hg, but the patient nevertheless undergoes LRV transposition.

• Left gonadal vein transposition (gonadoiliacaval or gonadocaval anastomosis A16.21.021, creation of a vaso-vasoanastomosis) is recommended as an alternative to LRV transposition in patients with LRV compression syndrome [10, 244, 338].

Level of Evidence (LE) 3, Grade of Recommendation (GR) C

Comments: shunting procedures are considered an adequate alternative to LRV transposition [9, 10, 244, 296, 297, 341]. This is due to the lower invasiveness of such operations with comparable clinical and hemodynamic outcomes. It has been noted that pain syndrome and hematuria are resolved in 90–95% of patients after left gonadal vein transposition.

3.6 Endovascular Treatment

Endovascular interventions on pelvic veins are characterized by minimal invasiveness, the possibility of performing the procedure under local anesthesia, and the ability to reliably eliminate pelvic venous reflux [4, 68]. Endovascular treatment of pelvic varices and pelvic congestion syndrome includes two distinct directions of interventional impact that pursue opposite goals. To eliminate pelvic venous reflux, occlusive (embolization) interventions using various sclerosing agents for local injections are used. Conversely, to restore the patency of main veins and normalize venous outflow through them, venous stenting aimed at expanding the vessel lumen is employed.

• For endovascular embolization of the gonadal veins (EGV) (A16.21.049, ovarian vein embolization), the use of metallic microcoils, liquid and foam forms of sclerosing agents for local injections, cyanoacrylate glue (323520 Brain vessel embolization material***), and combinations of sclerosing agents for local injections is recommended [2, 4, 24, 64, 75, 120, 233-235, 342, 343].

Level of Evidence (LE) 3, Grade of Recommendation (GR) B

Comments: historically, mechanical agents used included embolization coils (Endovascular embolization coils for non-brain vessels (323510 Non-brain vessel embolization coil***) made of stainless steel, nitinol, or platinum of various lengths, diameters, and shapes. Coils can be uncoated or coated, i.e., containing various fibrous materials on their surface that increase thrombogenicity (dacron, nylon, polyester, wool, silk, or PVA). Mechanical emboli also include a self-expanding cylindrical occluder (178270 Cardiac occluder***) knitted from a nitinol mesh [233] and occlusion balloons filled with sodium chloride. For chemical embolization, 1–3% sodium tetradecyl sulfate solution (C05BB04, sclerosing agent), 2–3% lauromacrogol-400 (lauromacrogol-400 C05BB02, sclerosing agent), N-butyl-2-cyanoacrylate, ethylene-vinyl alcohol copolymer (323520 Brain vessel embolization material***), absorbable gelatin sponge and gelatin foams (B02BC07, local hemostatic agent), and expanded polyvinyl alcohol particles (323490 Non-absorbable vascular embolization particles***) were used [63, 163, 342, 344]. There is no compelling evidence of the superiority of any particular sclerosing agents for local injections in reducing blood flow through the gonadal veins.

• EGV of the veins (A16.21.049, ovarian vein embolization) is recommended as an effective and safe method for treating pelvic congestion syndrome [2, 4, 53, 54, 24, 64, 75, 120, 233-235, 342].

Level of Evidence (LE) 3, Grade of Recommendation (GR) B

Comments: in the vast majority of studies, the technical success of EGV (reduction of blood flow through the vessel) was 100%. At the same time, the clinical efficacy (relief of symptoms and signs of the disease) of this treatment method varies widely from 48 to 100% [345-350]. It is known that 6–32% of patients do not experience significant relief from the procedure [3]. Post-embolization syndrome (PES) is observed in 20–54% of patients undergoing gonadal vein coil embolization [350-352]. Coil protrusion after EGV is detected in 4–8% of patients, coil migration into the heart chambers and pulmonary artery in 2% of patients, and allergic reactions to nickel [236, 281, 280, 348, 352-360]. Inconsistent data on the clinical efficacy of gonadal vein coil embolization and a significant number of complications associated with this procedure do not allow it to be considered as the reference standard method for treating pelvic congestion syndrome. Promising directions for the endovascular treatment of pelvic congestion syndrome include EGV with N-butyl-2-cyanoacrylate (323520 Brain vessel embolization material***) and sclerosing agents for local injections (lauromacrogol-400, sodium tetradecyl sulfate (C05BB04, sclerosing agent, C05BB02, sclerosing agent)) [361, 362].

• For endovascular embolization of the trunk and tributaries of the internal iliac veins (A16.21.049, ovarian vein embolization), the use of metallic coils is recommended [64, 72, 82, 94, 96, 127].

Level of Evidence (LE) 3, Grade of Recommendation (GR) C

Comments: coil implantation into the internal iliac vein trunk increases the risk of migration despite the coil diameter exceeding the vessel diameter by 20–30% [48, 266]. Furthermore, placing large-diameter coils promotes their protrusion [350, 358]. Therefore, selective embolization of internal iliac vein tributaries is advisable [99, 120, 345].

3.6.1 Endovascular Interventions on the Gonadal Veins

• Gonadal vein embolization (EGV) (A16.21.049, ovarian vein embolization) is recommended to be performed under local anesthesia with moderate intravenous sedation [2, 53, 54].

LNC 5 LeC C

LNC 5 LeC C

• Before performing EGV (A16.21.049, ovarian vein embolization), it is recommended to rule out compression syndromes by performing renal venography and pelvic phlebography [1, 2, 4, 234, 243, 346].

Level of Evidence (LE) 3, Grade of Recommendation (GR) C

• EGV is not recommended as the first-line intervention in nutcracker syndrome with an RCG > 3 mm Hg [4, 45, 54, 73, 104, 243, 347].

LNC 5 LeC C

• When performing mechanical EGV, it is recommended to use embolization coils (323510 Non-brain vessel embolization coil***) whose diameter exceeds the gonadal vein diameter by 20% [2, 54, 237, 342].

Level of Evidence (LE) 3, Grade of Recommendation (GR) C

Comments: when implanting a smaller-diameter coil, the probability of its migration is high. Placing a coil that significantly exceeds the diameter of the occluded vessel carries the risk of incomplete deployment [54, 218, 266, 342].

• For chemical EGV, it is recommended to use foam or liquid forms of sclerosing agents for local injections, N-butyl-2-cyanoacrylate, and ethylene-vinyl alcohol copolymer (323520 Brain vessel embolization material***) [2, 54, 163, 234, 280, 344, 362, 371].

Level of Evidence (LE) 3, Grade of Recommendation (GR) C

• To estimate the required volume of the sclerosing agent for local injections, it is recommended to use the volume of the previously injected contrast medium as a guide [64, 73].

LNC 4 LeC C

Comments: to prevent non-target embolization, it is advisable to use a volume of the sclerosing agent for local injections equal to or less than the volume of the test contrast injection.

• For combined embolization, it is recommended to use the "sandwich" technique, which combines the intraluminal administration of mechanical occluders (178270 Cardiac occluder***) into the vein and a foamed vein-sclerosing agent for local injections [54,99,237].

LNC 5 LeC C

• In ovarian vein embolization (OVE) (A16.21.049, ovarian vein embolization), the first coil is recommended to be placed above the junction of the tributaries of the caudal segment of the ovarian vein, and the last one below the confluence of the left ovarian vein into the left renal vein or the right ovarian vein into the inferior vena cava [53,54,64].

LNC 5 LeC C

3.6.2 Endovascular Interventions on the Internal Iliac Vein Trunk and Tributaries

• In patients with pelvic congestion syndrome (PCS), it is recommended to eliminate all sources of venous reflux by their embolization (A16.12.04, endovascular occlusive procedures) in order to minimize the risk of disease recurrence [54,73,64,120,343,345,347].

Level of Evidence (LE) 3, Grade of Recommendation (GR) B

Comments: the authors justify this tactic by the presence of anatomical connections between the pampiniform plexus and the tributaries of the internal iliac vein [120,345]. However, there are no comparative studies proving this statement. To date, it remains unclear how appropriate it is to perform endovascular occlusion of internal iliac vein tributaries simultaneously with OVE in patients with PCS without phlebographic confirmation of pelvic perinial reflux (PPR) [67,119,286].

• Selective embolization of internal iliac vein tributaries (A16.12.04, endovascular occlusive procedures) is recommended to eliminate PPR verified by pelvic phlebography [63,72,120,127,345,347].

LNC 4 LeC C

Comments: despite a 100% technical success rate of internal iliac vein tributary embolization, the clinical effect consisting in the disappearance of vulvar and gluteal varices was noted only in 40–60% of cases [47,50,99,266]. Thus, the elimination of PPR by embolization of refluxing pelvic veins does not lead to the elimination of vulvar/perineal varices, and patients need to undergo either perineal phlebectomy or sclerobliteration of varicose veins.

• Embolization of internal iliac vein tributaries (A16.12.04, endovascular occlusive procedures) is recommended for patients with recurrent vulvar, perineal, or gluteal varices and lower limb varicose veins caused by PPR visualized via pelvic phlebography [48,50,99].

LNC 4 LeC C

Comments: the development of recurrence of vulvar varicose veins or non-saphenous varicose veins of the lower extremities serves as an absolute sign of persistent PPR requiring correction. This, in turn, may indicate an underestimation of the clinical picture and insufficient diagnostic examinations performed prior to the initial surgery, as well as the omission of pelvic phlebography in a patient with vulvar varicose veins [54,156,345].

• Selective embolization of internal iliac vein tributaries (A16.12.04, endovascular occlusive procedures) is recommended if communicants between them and the subcutaneous veins of the perineum and lower extremities are visualized [54,73,84,237].

LNC 4 LeC C

Comments: reliable information on the presence of an anatomical connection between the pelvic, perineal, and lower extremity veins can only be obtained using pelvic phlebography. If such a connection is visualized, coil embolization of the connecting vein is mandatory. In the absence of an obvious connection between the pelvic, perineal, and lower extremity veins, embolization of internal iliac vein tributaries is not indicated [67,119].

Level of Evidence (LE) 3, Grade of Recommendation (GR) C

Comments: implantation of embolization coils (323510 Extra-cerebral vessel embolization coil***) into the internal iliac vein trunk is accompanied by a significant increase in the risk of their migration due to increased vessel distensibility and high blood flow volume in the internal iliac vein.

• Prior to chemical embolization of internal iliac vein tributaries, it is recommended to perform preliminary balloon occlusion of the internal iliac vein lumen [73,362,371].

LNC 4 LeC C

Comments: the duration of balloon occlusion to prevent migration of the embolization agent into the proximal venous bed must be at least 5 minutes.

3.6.3 Endovascular Interventions on the Left Renal Vein

• Left renal vein stenting (A16.12.028, vascular stent placement) is recommended as an effective and safe method for treating nutcracker syndrome and correcting left-sided renal venous hypertension [9,10,54,131,146,164,291].

Level of Evidence (LE) 3, Grade of Recommendation (GR) B

Comments: in a systematic review, Velasquez C.A. et al. report high efficacy of left gonadal vein stenting and rare procedure-related complications, specifically stent migration observed in 3.3–6.6% of cases [10].

• When performing left gonadal vein stenting (A16.12.028, vascular stent insertion), it is recommended to implant a stent with a diameter 20% exceeding the diameter of the vessel [9,54,247,291].

LNC 5 LeC C

• It is recommended to consider cessation of gonadal vein opacification and normalization of retrograde blood flow values as criteria for the technical success of left gonadal vein stenting [53,54,73].

LNC 4 LeC C

• To ensure complete stent expansion and prevent its migration, balloon post-dilatation is recommended [9,73,247].

LNC 4 LeC C

3.6.4 Endovascular Interventions on the Iliac Veins

• Iliac vein stenting (A16.12.028, vascular stent insertion) is recommended as the treatment method of choice for patients with May-Thurner syndrome [4,109,166,167,187,255,371-375].

Leveled Research Evidence (LE) 2 Grade of Recommendation (GR) B

Comments: the primary, primary-assisted, and secondary patency rates were 91%, 95%, and 98%, respectively, at 12 months, and 77%, 92%, and 94%, respectively, at 36 months [109,113,114,366]. The complication rate (stent migration, dislocation, and thrombosis) of iliac vein stenting in May-Thurner syndrome was less than 2% [372,377,378].

To prevent stent dislocation and reduce the incidence of the "jailing" effect (stent coverage of the contralateral iliac vein) and contralateral iliofemoral thrombosis, the use of dedicated venous stents is recommended [366-370]. A comparative study of outcomes between linear and composite stent configurations demonstrated superior results in patients implanted with composite stents. In recent years, studies have emerged indicating better outcomes with the use of dedicated angled venous stents, which significantly reduce the rate of contralateral common iliac vein coverage by the stent and conical narrowing of the cranial stent segment [363,367,370].

• Iliac vein stenting (A16.12.028, vascular stent insertion) in asymptomatic patients with compressive stenosis of the left common iliac vein is not recommended [16,111,112,366,374].

LNC 4 LeC C

• Following stent implantation, long-term (up to 6 months) multi-component antiplatelet and anticoagulant therapy is recommended [255,367,368,379-382].

Level of Evidence (LE) 3, Grade of Recommendation (GR) B

3.6.5 Prevention of venous thromboembolism (VTE) after interventions on pelvic, renal, and iliac veins

Surgical and endovascular interventions on the pelvic veins are associated with various complications, including venous thromboembolism (VTE). To date, specific guidelines for the prevention of VTE after pelvic vein surgery have not been developed, leading to divergent views regarding the necessity and methods of VTE prevention in such patients. Conversely, accumulated experience in iliac vein stenting for May-Thurner syndrome has allowed for a comprehensive analysis of treatment outcomes and the use of medical VTE prophylaxis in these patients [255].

Sudden cessation of blood flow in the gonadal veins following their resection or embolization is accompanied by increased blood pooling in dilated parametrial and uterine veins within the first 24 hours post-procedure. This results in the development of pelvic vein thrombosis (PVT). Furthermore, the placement of metallic devices (coils, occluders, stents) within the vessel lumen or the administration of local injection sclerosing agents serves as an additional trigger for thrombus formation not only in the pelvic veins but also in the deep veins of the lower extremities.

• Patients undergoing endovascular gonadal vein embolization are recommended to undergo duplex ultrasound to assess pelvic vein patency. If non-target vein thrombosis is detected, conservative therapy is recommended. Alternatively, detected non-target vein thrombosis should be regarded as an adverse event requiring conservative therapy [171,172].

LNC 4 LeC C

Comments: endovascular occlusion entails the formation of thrombotic masses within the embolized vessel (i.e., the gonadal vein). The formation of thrombi in the internal iliac veins, uterine veins, tributaries or the trunk of the internal spermatic vein, and deep veins of the lower extremities should be considered as non-target vein thrombosis. Restoration of lumen patency (recanalization) in the pelvic or deep lower extremity veins leads to the destruction of their valve apparatus and the development of post-thrombotic syndrome [81]. Non-target vein thrombosis following endovascular gonadal vein embolization is an adverse outcome requiring additional treatment and a short hospital stay.

• Non-target vein thrombosis following gonadal vein resection is recommended to be considered as an adverse event [16,171].

LNC 4 LeC C

• To prevent pelvic vein thrombosis after gonadal vein resection or embolization, early patient mobilization is recommended [99,120,275,327,330].

LNC 4 LeC C

Comments: gonadal vein resection is a minor surgical procedure characterized by a duration of no more than 60 minutes and minimal invasiveness [16,326,329,334]. 2-3 hours after surgery, patients can be mobilized, allowed to get out of bed, and walk independently. Following endoscopic interventions, patients may be discharged from the surgical inpatient unit for outpatient treatment and follow-up on the same day or 24 hours postoperatively.

• For the prevention of pelvic vein thrombosis after gonadal vein resection or embolization, it is recommended to prescribe heparin group drugs 6-8 hours after surgery [171,172,236].

LNC 4 LeC C

Comments: the incidence of pelvic vein thrombosis following gonadal vein resection, regardless of the access approach (open or endoscopic), is 10%, and after gonadal vein embolization, it is 47% [171,281]. Pelvic vein thrombosis is most frequently detected after bilateral interventions (79% after gonadal vein embolization or resection). Currently, there are no studies investigating the dynamics of the thrombotic process in the pelvic veins following interventions on the gonadal veins. Therefore, it is impossible to predict the further progression of thrombosis or to rule out the spread of thrombi to the inferior vena cava and common iliac vein with the formation of a free-floating tail, which poses a real threat of pulmonary embolism. Given these facts, as well as the impossibility of applying adequate compression to the venous outflow from the pelvic organs, anticoagulant prophylaxis is the only effective way to prevent thrombus formation in the internal iliac veins, myometrial veins, internal iliac vein tributaries, and the development of pulmonary embolism.

• For the prevention of venous thromboembolism after left renal or iliac vein stenting, it is recommended to use heparin group drugs at a prophylactic dose (1 mg/kg of body weight once daily subcutaneously into the anterior abdominal wall) [16,215,237,255,291,294,383,384].

LNC 4 LeC C

Comments: placement of a metal device in a major vein serves as a significant factor for venous thrombus formation. To prevent this, it is advisable to use parenteral heparin groups for 10 days, followed by their discontinuation and the prescription of oral antithrombotic agents for at least 6 months [16,108,247,295,385,386]. Re-endothelialization of the stent occurs within 6 months, which is why it is recommended to use antithrombotic agents during this period. According to Bi et al., after iliac vein stenting, warfarin should be used under INR monitoring (target range: 2.5–3) for 3–6 months, or dipyridamole in case of intolerance or resistance to warfarin [387]. A number of authors recommend the combined use of antithrombotic agents, justifying this by the different mechanisms of action of these drugs on blood hemorheology [385,386,388].

Recurrence of Pelvic and Vulvar Varicose Veins

Recurrence of Pelvic Varices

Long-term outcomes of surgical and endovascular treatment of pelvic varices and pelvic congestion syndrome are characterized by a wide range of recurrence rates of disease symptoms. Following surgical treatment of pelvic congestion syndrome (ligation or resection of gonadal veins), disease recurrences are noted in 6–10% of patients [220,262,280,281,327,328]. Clinically, pelvic varices may be accompanied by the recurrence of pelvic pain, heaviness in the hypogastric region, and dyspareunia. Given the deep location of the pelvic veins, their visual detection is impossible, and their visualization is only accessible using instrumental diagnostic methods. Dilation and reflux in unligated tributaries of the gonadal veins or in an accessory gonadal vein lead to repeated dilation of the pelvic veins and the appearance of disease symptoms.

Following endoscopic interventions on the gonadal veins, recurrence of pelvic congestion syndrome was absent in 100% of patients during 3–5 years of follow-up. The rate of recurrence of pelvic congestion syndrome symptoms after gonadal vein embolization varies from 2 to 32% over 2–8 years of follow-up [54,120,243,345,347,350,392-395]. The authors consider the causes of pelvic congestion syndrome recurrence to be persistent reflux in the gonadal veins after embolization, the presence of additional gonadal vein trunks or satellite veins not embolized or resected during the primary intervention, the presence of a large gonadal vein tributary communicating with the pampiniform plexus and not ligated during gonadal vein resection, or May-Thurner syndrome not diagnosed prior to gonadal vein resection or embolization [73,120,220,243,345,347,350,391]. Dilation and reflux in unligated tributaries of the gonadal veins (or tributaries outside the embolization zone) or in an accessory gonadal vein lead to repeated dilation of the pelvic veins and the appearance of disease symptoms. Tactical approaches to the treatment of recurrent pelvic congestion syndrome have not been defined; based on unsystematized literature data, repeat interventions include endovascular and surgical methods. The emergence of clinical manifestations of the disease after gonadal vein embolization can be managed either by repeat coil placement in the gonadal vein, embolization of an additional gonadal vein trunk, or by performing a resection of the accessory gonadal vein [73,120,391,393]. In the case of pelvic congestion syndrome recurrence after gonadal vein resection caused by the presence of a large unligated gonadal vein tributary localized in the stump of the resected vessel, blood flow through it can be reduced by embolization of the gonadal vein stump [220]. If May-Thurner syndrome is detected as the cause of pelvic congestion syndrome recurrence, stenting of the left common iliac vein is indicated [220].

• Under the term recurrence of pelvic congestion syndrome, it is recommended to consider the appearance of disease symptoms against the background of dilated pelvic veins with reflux in them according to duplex ultrasound data following a prior intervention on the gonadal veins [54,220,391,395].

LNC 4 LeC C

• The choice of treatment method for recurrent pelvic congestion syndrome is recommended to be carried out depending on the nature of the primary gonadal vein intervention and the presence/absence of compressive iliac vein stenosis [73,84,220,347].

LE 4 GSR C

Recurrence of vulvar and perineal varices

Studies on the treatment of vulvar/perineal varices are limited to case reports and case series [282,285,286,290,316-318,396-397], and in rare cases, cohort studies with short follow-up periods [66,289]. This makes it impossible to objectively assess treatment outcomes and disease recurrence rates. However, available data indicate that venectomy and sclerotherapy are effective treatment methods, with recurrence rates of vulvar and perineal varices ranging from 2.9% to 3.2% following their use. Endovascular embolization of the internal iliac vein trunk or its tributaries (A16.12.04, endovascular occlusive procedures) in the treatment of vulvar and perineal varices is accompanied by the disappearance of varicose veins in 31% of patients, a decrease in the severity of varices in 20%, and no change in 49% [48]. No studies assessing the recurrence of vulvar and perineal varices after internal iliac vein tributary embolization were found in the available medical literature.

• Recurrence of vulvar and perineal varices is recommended to be defined as the appearance of varicose veins on the labia majora and minora after their sclerobliteration or surgical removal [66,289,317].

Level of Evidence (LE) 3, Grade of Recommendation (GR) B

• The causes of vulvar/perineal varicose vein recurrence after venectomy or sclerobliteration of vulvar/perineal veins are recommended to be considered:

– Technical aspects of venectomy/sclerobliteration performance;

– Persistent ongoing pelvoperineal reflux;

– Pregnancy developing in the short term (1–3 months) after intervention on the vulvar/perineal veins [288,317,403].

LE 4 GSR C

• The choice of treatment method for recurrent pelvic varicose veins is recommended to be made depending on the type of primary intervention and the results of pelvic phlebography [66,57].

LE 4 GSR C

Complications of Pelvic and Vulvar Varicose Veins

Pelvic Vein Thrombosis (Parametrial, Uterine, Gonadal)

Pelvic vein thrombosis (PVT) most frequently occurs in the postpartum period [398]. The incidence of PVT ranges from 0.05% to 0.18%, accounting for, according to various authors, 1 case per 600 deliveries and 1 case per 1000 patients undergoing pelvic surgery [401-402]. Pulmonary embolism (PE) in these patients occurs in 13–33%, and fatal pulmonary embolism is recorded in 4% [29,31]. To a certain extent, these data can be extrapolated to patients with pelvic varicose veins and pelvic congestion syndrome. At the same time, the postpartum period is characterized by such significant changes in a woman's body that these data cannot be fully associated with the development of PVT outside of pregnancy and childbirth. There are currently no studies on the development of PVT among patients with pelvic varicose veins, making it impossible to formulate evidence-based recommendations on this issue. Nevertheless, based on real-world clinical practice and research data on postpartum pelvic vein thrombosis, the following can be stated:

• Pelvic vein thrombosis is recommended to be considered as a complication of pelvic varicose veins requiring anticoagulant therapy (ATC group: antithrombotic agents, B01A) [171,172,236].

LE 4 GSR C

• In the treatment of patients with pelvic varicose veins and pelvic vein thrombosis, it is recommended to use the anticoagulant therapy regimen (ATC group: antithrombotic agents, B01A) employed in the treatment of distal deep vein thrombosis of the extremities [236,401-403].

LE 4 GSR C

Comments: Amin T.N. et al. (2021), based on the observation of 50 gynecological patients with ovarian vein thrombosis, report a favorable course of this condition without anticoagulant therapy in the majority of patients [404]. This issue requires further investigation.

• If a free-floating thrombus is detected in gonadal veins (gonado-caval or gonado-renal thrombosis), it is recommended to perform open or endovascular thrombectomy from the inferior vena cava or left renal vein (A16.12.003.001, aspiration endovascular thrombectomy) [405–407].

LE 4 GSR C

4. Medical Rehabilitation and Sanatorium-Resort Treatment

The rehabilitation program for patients with pelvic varices and pelvic venous disorders includes a set of measures aimed at the compensation of lost (impaired) functions and activity limitations. The goal of physical therapy for pelvic varices is to reduce pain, pelvic dysfunction, and improve quality of life and functional capabilities. To date, international databases publishing the results of medical research contain only isolated studies on the use of physical therapy methods in the treatment of pelvic congestion syndrome. Since chronic pelvic pain is the main clinical symptom of pelvic congestion syndrome, physical therapy methods can be used to reduce the pain syndrome, which negatively affects the quality of life and personal relationships of patients and leads to serious physical and psychological problems [409,410]. Patients with chronic pelvic pain report a high frequency of anxiety, depression, and physical distress [411].

LNC 4 LeC C

Comments: lifestyle modification recommendations include: bladder training to control urinary urgency; exercises for the pelvic floor muscles supporting the bladder (Kegel exercises – multiple contractions and relaxation of the pelvic muscles); trigger point and myofascial release techniques; dietary modifications; breathing and relaxation techniques. In fact, as the cited studies have shown, pelvic floor physical therapy is considered an option for the conservative treatment of pelvic floor dysfunction when the pelvic floor muscles are too tight and/or weak, lack endurance, or are difficult to coordinate with other muscle groups.

• To relieve chronic pelvic pain, the rehabilitation program for patients with pelvic congestion syndrome is recommended to include: manual therapy for soft tissue and visceral mobilization, lymphatic drainage massage, posture correction, and neuromuscular pelvic floor re-education using biofeedback [419].

Level of Evidence (LE) 2, Grade of Recommendation (GR) A

Comments: pelvic floor physical therapy can be offered as a treatment for chronic pelvic pain [420]. Small-sample studies support the efficacy of biofeedback in chronic pelvic pain [421–423]. Biofeedback helps patients identify areas of muscle tension so they can learn to relax those areas for better pain relief.

• Patients with pelvic congestion syndrome are recommended to receive somatocognitive therapy, a hybrid of cognitive psychotherapy and physical therapy, to reduce pain, improve distress, and enhance motor functions [77,424,425].

LE 1 LOC A

• Patients with pelvic congestion syndrome 3 months after surgical or endovascular treatment are recommended spa-and-resort treatment at climatic and balneological resorts for physical and psychological rehabilitation utilizing climate therapy, terrain cures, hypopressive exercises, and psychological counseling [418,419,426].

Level of Evidence (LE) 2, Grade of Recommendation (GR) A

5. Prevention and Dispensary Observation

In patients with pelvic varices and pelvic venous disorders, prevention should be aimed at the timely detection of pelvic varices, compression stenoses of the left renal and common iliac veins, and their surgical or endovascular correction when indicated [425].

LNC 4 LeC C

Comments: pelvic varices are one of the frequent causes of chronic pelvic pain [36,37]. Timely detection of pelvic varices as a cause of chronic pelvic pain allows for adequate conservative, surgical, or endovascular treatment. Similarly, early detection of Nutcracker and May-Thurner syndromes as the cause of pelvic varices will enable timely surgical or endovascular intervention aimed at preventing disease progression.

In the absence of clinical manifestations of pelvic varices, medical prevention of disease progression is not indicated due to the lack of data on any proven effective methods. Patients are indicated for clinical follow-up by a surgeon (B04.057.001) and regular (once a year) duplex ultrasound scanning of the pelvic veins.

LNC 4 LeC C

Comments: the detection of pelvic vein dilation with reflux upon duplex ultrasound scanning is not a sign of pelvic venous disease. Under conditions of female sex hormone hyperproduction and increased hemodynamic load on the pelvic veins, they naturally dilate. Diagnostic, preventive, and therapeutic measures should be carried out after childbirth and the lactation period, when pelvic venous hemodynamics are no longer subject to the influence of the aforementioned factors.

6. Organization of Medical Care

Medical care for patients with pelvic varices and pelvic venous disorders should be provided in the following settings:

- on an outpatient basis (under conditions not providing for round-the-clock medical observation and treatment);

- in a day hospital (in conditions providing medical observation and treatment during the day, not requiring round-the-clock medical observation and treatment);

- on an inpatient basis (under conditions providing for round-the-clock medical observation and treatment).

Medical care for patients with pelvic varices and pelvic venous disorders is provided in the form of:

- primary health care;

- emergency medical care, including specialized emergency medical care;

- specialized medical care, including high-tech medical care.

Primary health care for patients with lower limb varicose veins includes:

1) primary care physician-delivered medical and sanitary care;

2) primary specialized medical and sanitary care.

Primary care physician-delivered medical and sanitary care is provided by a district physician or general practitioner (family physician) in an outpatient setting. Upon detecting signs of pelvic varices and vulvoperineal varices, the patient is referred to a relevant specialist to receive primary specialized medical and sanitary care.

Primary specialized medical and sanitary care for patients with pelvic varices and vulvoperineal varices is provided by surgeons and cardiovascular surgeons. Ultrasound diagnostics physicians are involved in performing diagnostic examinations.

The provision of outpatient medical care to patients with pelvic varices and vulvoperineal varices is limited to additional investigations (MSCT, MRI) aimed at clarifying the diagnosis and ruling out/confirming compression stenoses of the left renal vein and iliac veins. In cases of isolated dilation of parametrial and uterine veins, presence of vulvoperineal varices, and absence of renal and iliac vein pathology, patients may undergo sclerobliteration of vulvar/perineal varicose veins, provided a surgeon or cardiovascular surgeon experienced in performing sclerotherapy in this category of patients is available.

Emergency, including specialized, medical care is provided to patients with pelvic varices and vulvoperineal varices in the event of life-threatening conditions, such as embolism-risk pelvic vein thrombosis (gonadal vein thrombosis extending to the inferior vena cava or left renal vein, internal iliac vein thrombosis). If parametrial vein thrombosis or vulvar thrombophlebitis is detected, outpatient treatment is possible. In other cases, patients with pelvic varices and vulvoperineal varices remain mobile and seek primary health care independently.

Specialized, including high-tech, medical care is provided in an inpatient setting (day hospital) by surgeons, cardiovascular surgeons, and endovascular surgeons. Ultrasound diagnostics physicians, diagnostic radiology physicians, and endovascular diagnostics physicians are involved in performing diagnostic examinations.

Indications for elective inpatient hospitalization of patients with pelvic varices are:

- surgical or endovascular treatment of pelvic congestion syndrome;

- surgical or endovascular treatment of Nutcracker syndrome;

- endovascular treatment of May-Thurner syndrome.

Not an indication for hospitalization:

- a course of conservative treatment that does not involve surgical correction of pathology in patients with pelvic varices;

- a course of sclerotherapy for vulvoperineal varices.

Indications for emergency inpatient hospitalization of patients with pelvic varices are:

- embolism-risk pelvic vein thrombosis (gonadal vein thrombosis extending to the inferior vena cava or left renal vein, internal iliac vein thrombosis).

Criteria for discharge from the hospital:

- completed surgical or endovascular treatment of pelvic varices;

- completed surgical or endovascular treatment of Nutcracker and May-Thurner syndromes;

- absence of pronounced pain syndrome;

- absence of postoperative/post-embolization pelvic vein thrombosis;

- absence of stented vein thrombosis;

- absence of retroperitoneal hematoma.

7. Additional Information

Not provided.

Criteria for Evaluating the Quality of Medical Care

References

Appendix A1. Working Group Composition

1. Apkhanova T.V., Cand. of Sci. (Med.), member of the Russian Society of Cardiology (RSC), member of the European Society of Cardiology (ESC), member of the American Vein and Lymphatic Society (USA);

2. Akhmetzyanov R.V., Dr. Sc. (Med.), Member of the Association of Phlebologists of Russia (APR), the Russian Society of Angiologists and Vascular Surgeons (RSAVS), and the Russian Society of Surgeons (RSS);

3. Bredikhin R.A., Dr. Sc. (Med.), Member of the Association of Phlebologists of Russia (APR), the Russian Society of Angiologists and Vascular Surgeons (RSAVS), and the Russian Society of Surgeons (RSS);

4. Burenchev D.V., Dr. Sc. (Med.), Chairman of the Presidium of the Moscow Regional Branch of the Russian Society of Roentgenologists and Radiologists (MRBRSRR), Member of the European Society of Radiology (ESR), the European Society of Emergency Radiology (ESER), the National Society of Neuroradiologists (RusNR), and the European Society of Neuroradiology (ESNR);

5. Gavrilov S.G., Dr. Sc. (Med.), Professor, Member of the Scientific Council of the Association of Phlebologists of Russia (APR), Member of the Russian Society of Surgeons (RSS);

6. Efremova O.I., Ph.D. in Medicine, member of the Association of Phlebologists of Russia (APR);

7. Zolotukhin I.A., Dr. of Sci. (Med.), Professor, Professor of the RAS, Executive Secretary of the Association of Phlebologists of Russia (APR);

8. Kamaev A.A., Member of the Association of Phlebologists of Russia (APR), the Russian Society of Angiologists and Vascular Surgeons (RSAVS), and the Russian Society of Surgeons (RSS);

9. Kirienko A.I., Dr. Sc. (Med.), Academician of the Russian Academy of Sciences, Honorary President of the Association of Phlebologists of Russia (APR), Vice-President of the Russian Society of Surgeons (RSS), Member of the Presidium of the Russian Society of Angiologists and Vascular Surgeons (RSAVS), laureate of the State Prize of the Russian Federation, the Government Prize of the Russian Federation, and the Academician A.N. Bakulev and Academician E.N. Meshalkin Prizes;

10. Konchugova T.V., Dr. Sc. (Med.), Professor, Member of the Association of Physiotherapy and Medical Rehabilitation;

11. Kulchitskaya D.B., Dr. Sc. (Med.), Professor, Member of the Association of Physiotherapy and Medical Rehabilitation;

12. Mishakina N.Yu., Cand. Sc. (Med.), Member of the Association of Phlebologists of Russia (APR);

13. Pryadko S.I., Cand. Sc. (Med.), Member of the Executive Board of the Association of Phlebologists of Russia (APR), Deputy Chairman of the "Phlebology and Lymphology" Section of the Association of Cardiovascular Surgeons of Russia (ACVSR), European Society for Vascular Surgery (ESVS), European Society of CardioVascular Surgery (ESCVS);

14. Rachin A.P., Dr. Sc. (Med.), Professor, President of the National Association of Experts in Comorbid Neurology, Member of the Interregional Society "North-West Pain Study Society";

15. Sazhin A.V., Dr. Sc. (Med.), Professor, Corresponding Member of the Russian Academy of Sciences, Secretary General of the Russian Society of Endoscopic Surgeons (RSES);

16. Seliverstov E.I., Dr. Sc. (Med.), Member of the Association of Phlebologists of Russia (APR);

17. Soroka V.L., Radiologist;

18. Stoyko Yu.M., Dr. Sc. (Med.), Professor, Honored Doctor of the Russian Federation, Honored Worker of Science of the Russian Federation, laureate of the Government Prize of the Russian Federation, Honorary President of the Association of Phlebologists of Russia (APR), Board Member of the Russian Society of Angiologists and Vascular Surgeons (RSAVS), Honorary Member of the European Venous Forum (EVF);

19. Suchkov I.A., Dr. Sc. (Med.), Professor, President of the Association of Phlebologists of Russia (APR), Member of the Presidium of the Russian Society of Surgeons (RSS), Vice-President of the Russian Society of Angiologists and Vascular Surgeons (RSAVS);

20. Fomina E.E., Dr. Sc. (Med.), Associate Professor, Member of the Russian Association of Ultrasound Diagnostics Specialists in Medicine (RASUDM);

21. Tsukanov Yu.T., Dr. Sc. (Med.), Professor, Member of the Association of Phlebologists of Russia (APR), Member of the Russian Society of Surgeons (RSS);

22. Shimanko A.I., Dr. Sc. (Med.), Professor, Member of the Executive Board of the Association of Phlebologists of Russia (APR).

All members of the Working Group confirmed the absence of financial support or other conflicts of interest in the preparation of these guidelines.

Appendix A2. Methodology for Developing Clinical Guidelines

Target audience for these clinical guidelines:

Target audience of the developed clinical guidelines:

1. Cardiovascular surgeon;

2. Surgeon;

3. Ultrasound diagnostics physician;

4. Medical students, residents, postgraduate students.

These recommendations are based on a comprehensive analysis of evidence presented in the global literature and obtained through the clinical application of modern principles and methods for diagnosing and treating pelvic and vulvar varices. The main provisions of the recommendations are ranked in accordance with Order No. 103n of the Ministry of Health of the Russian Federation dated February 28, 2019, "On Approval of the Procedure and Timeframes for the Development of Clinical Guidelines, Their Revision, the Standard Template for Clinical Guidelines, and Requirements for Their Structure, Composition, and Scientific Validity of Information Included in Clinical Guidelines." The recommendations were prepared in accordance with the Methodological Recommendations for Assessing the Scientific Validity of Information Included in Clinical Guidelines by the Center for Expertise and Quality Control of Medical Care of the Ministry of Health of the Russian Federation, 2019.

Table 1. Scale for assessing levels of evidence (LE) for diagnostic methods (diagnostic interventions)

Table 2. Scale for assessing the levels of evidence (LE) for prevention, treatment, and medical rehabilitation methods, including those based on natural therapeutic factors (preventive, therapeutic, and rehabilitation interventions)

Table 3. Scale for assessing the levels of evidence for recommendations (LER) for prevention, diagnostic, treatment, and medical rehabilitation methods, including those based on natural therapeutic factors (preventive, diagnostic, therapeutic, and rehabilitative interventions)

Procedure for updating clinical guidelines

The mechanism for updating clinical guidelines provides for their systematic revision at least once every three years, as well as upon the emergence of new evidence-based medicine data on the diagnosis, treatment, prevention, and rehabilitation of specific diseases, or in the presence of justified additions/comments to previously approved clinical guidelines, but no more frequently than once every 6 months.

Appendix A3. Reference Materials

These clinical guidelines were developed taking into account the following regulatory legal documents:

1. Federal Law No. 323-FZ of November 21, 2011, "On the Fundamentals of Protecting the Health of Citizens in the Russian Federation";

   Federal Law No. 323-FZ of November 21, 2011 (as amended on December 28, 2024) "On the Fundamentals of Protecting the Health of Citizens in the Russian Federation";

2. Order of the Russian Ministry of Health No. 918n of November 15, 2012, "On Approval of the Procedure for Providing Medical Care to Patients with Cardiovascular Diseases";

3. Order of the Russian Ministry of Health No. 922n of November 15, 2012, "On Approval of the Procedure for Providing Medical Care to Adult Patients in the Specialty 'Surgery'";

4. Order of the Ministry of Health of the Russian Federation No. 103n of February 28, 2019, "On approval of the procedure and timelines for the development of clinical guidelines, their revision, the standard form of clinical guidelines and requirements for their structure, composition, and scientific validity of the information included in the clinical guidelines."

Appendix A3.1 Results of surgical and endovascular interventions on gonadal veins in the treatment of Pelvic Congestion Syndrome

Appendix B. Physician Action Algorithms

Algorithm 3. Physician's actions in case of asymptomatic pelvic varices. PV – pelvic varices; DUS – duplex ultrasonography; GV – gonadal veins; PV – parametrial veins; UV – uterine veins; LRV AMK – aortomesenteric compression of the left renal vein.

Appendix C. Patient Information

Pelvic varices are accompanied by dilatation of the uterine and ovarian veins, which in 60-70% of women lead to the development of pelvic congestion syndrome, while in 30-40% of cases, venous dilatation is completely asymptomatic and does not affect the daily and professional activities of women. The onset of the disease is primarily associated with repeated pregnancies and childbirths, and it is most frequently diagnosed in parity-positive women aged 25–35 years. However, the condition can also occur in nulliparous women and those over 40–50 years of age. In addition, the causes of pelvic varices may include stenosis of the left renal or left common iliac veins, which impairs blood outflow through these veins, increasing the load on the pelvic veins and leading to their subsequent varicose transformation. The long-standing impairment of venous outflow from the pelvic organs leads to venous blood stasis in the uterus and appendages, and the development of chronic pelvic pain (CPP), which is the most striking and dramatic symptom of pelvic congestion. The primary efforts of physicians are directed precisely at eliminating CPP.

What is chronic pelvic pain?

Chronic pelvic pain is intermittent or constant pain in the lower abdomen and pelvic region that bothers a woman for more than 6 months and is not associated with pregnancy, the menstrual cycle, or sexual intercourse. CPP is a common problem and frequently leads to disability. This condition affects 25% of women. More than half of women with CPP must restrict their daily activity for one or more days a month, and 90% experience pain during sexual intercourse. Almost half of women with CPP note a worsening of mood and depression. Despite all the suffering caused by chronic pelvic pain, physicians are not always able to diagnose it and recommend an effective treatment method. Frequently, the initial cause triggering the pain may diminish or completely resolve, but the pain persists. This creates difficulties in identifying the cause of the pain and providing adequate treatment. Pain may be localized in the lower abdomen, vulva/vagina, perineum, anus, or coccyx. Features of pelvic venous pain include its occurrence against the background of pelvic varices, localization in the right or left iliac regions or suprapubic area, a constant dull, aching character that intensifies with physical exertion, prolonged standing, sitting, and lifting or carrying heavy objects (over 10 kg). Other manifestations of the disease include pain after sexual intercourse lasting from 15 minutes to 1 day post-coitus, a sensation of heaviness and discomfort in the lower abdomen, and frequent urination. The presence of varicosities on the external genitalia is an obvious sign of pelvic venous pathology. Despite these seemingly simple symptoms of pelvic varices, similar signs are very frequently found in various diseases of the pelvic organs, kidneys, ureters, spine, peripheral nerves, pelvic muscles, or psychological distress. In this regard, it is important to know what CPP is and what diagnostic and treatment methods physicians use to treat it.

What is the difference between acute and chronic pain?

Acute pain occurs when there is damage to the body, such as an inflammatory process in the abdominal cavity. In this case, there is an obvious cause for the pain. Chronic pain is completely different. The initial cause is difficult to eliminate. New pain-generating factors appear in surrounding tissues, such as muscles and connective tissue. Nerves transmitting impulses from painful areas often become excessively sensitive. This is caused by changes in the nervous system, muscles, soft tissues, and sometimes other pelvic organs. Chronic pain is often considered a separate nosological entity.

What is "chronic pelvic pain syndrome"?

When constant, severe pain continues for a long period of time, it exhausts a person physically and mentally. To cope with the pain, a person may change their emotional and behavioral responses. When pain persists for a long time and is sufficiently intense, it changes a person emotionally, altering their behavior to cope with it. This condition is called chronic pelvic pain syndrome.

Women with this pathological condition often experience the following:

• Pain lasting for 6 months or longer.

• Standard treatments do not relieve the pain or provide only minor relief.

• The pain is more severe than would be expected from the injury, surgery, or disease that originally caused the pain.

• Insomnia or sleepiness, decreased appetite, slowed movements and reactions, symptoms of depression, including despondency and tearfulness.

• Feelings of anxiety and helplessness.

• Decreased physical activity.

• Lowered self-esteem at home and at work.

CPP combines physical symptoms (pain, insomnia, loss of appetite) and psychological symptoms (feelings of anxiety, behavioral changes, changes in family and work relationships due to physical and psychological problems).

Can pelvic pain involve other parts of the body?

A person suffering from pelvic pain may notice that discomfort begins to appear in other parts of the body. Pelvic pain is typically characterized by muscle tension. Patients may notice persistent changes in the pelvic muscles and even the skin of the pelvic region. Pelvic muscle tension can affect the bladder and intestines. Pain in the lower back and legs is also possible due to the involvement of muscles and nerves. Once started, these sensations can become more pronounced and agonizing over time than the pelvic pain that contributed to their appearance. This is precisely why physicians specializing in the treatment of chronic pelvic pain examine all your tissues and organs, not just the reproductive system.

How do I feel pain?

Damaged tissues send signals through specialized nerve cells to the spinal cord. The spinal cord acts as a "gate". It allows signals to pass into the brain, can stop them, or alter them by making them stronger or weaker. How you perceive pain depends on your mood, your environment, and other processes occurring in your body at that time. When a person has chronic, long-term pain, the spinal cord "gate" can be damaged. This can cause it to remain open even after the damaged tissues have healed. When this happens, the pain persists despite the cure of the original cause.

What are the characteristics of chronic pelvic pain?

There are several main factors:

Pathology at the site of origin.

There is or was damage (pathology) at the site (primary site) where the pain first started. This damage can be endometriosis, an ovarian cyst, bowel pain, a bladder infection, or adhesions (scar tissue after surgery), pelvic varicosities. The pathology can be nerve damage in the abdominal wall, pelvis, or pelvic floor.

Reflex pain or excitation stimulation

Your body has two types of nerves: visceral nerves carry impulses from organs and structures in your abdomen and chest (stomach, intestines, lungs, heart, etc.); somatic nerves carry messages from the skin and muscles. Both types of nerves travel to the same sides of the spinal cord. When your visceral nerves are stimulated over a long period by chronic, continuous pain, some of this stimulation can spread to somatic nerves, which can carry the pain to the muscles and skin. In CPP, somatic nerves can carry pain to the pelvis and abdominal wall muscles and skin. This means your pain may start in the bladder, and you will also feel it in the skin and muscles, or vice versa. Excitation stimulation refers to an increase in nerve excitability/signal transmission to the spinal cord and brain, which is perceived as pain. Excitation stimulation can result from chronic nerve stimulation or a change in the brain's processing of signals from internal organ and muscle nerves.

Myofascial pain

This type of pain can be a primary source of pain unrelated to organ pathology, or a secondary source resulting from a reflex response (viscerosomatic reflex). Trigger points often develop in affected muscles. Trigger points are specific areas of tenderness that occur in the abdominal muscle wall. Trigger points may begin as just one symptom of your pelvic pain or they can be a major source of pain for you. For this reason, treating trigger points can significantly reduce pain. Pelvic nerves, such as the pudendal nerve, can also stimulate pelvic muscles and cause myofascial pain.

How does the brain respond to chronic pain syndrome?

The brain influences your emotions and behavior. It also interacts with your spinal cord and affects how you perceive visceral and reflex pain. For example, if you are depressed, your brain will allow more pain signals to pass into the spinal cord and brain. Of course, areas of the brain are also "switched off" when you have chronic pain and cannot effectively inhibit pain signals. Sometimes the nervous system is overloaded with pain signals, which can lead to increased sweating, nausea or loss of appetite, fatigue, and other problems. It is important to remember that treatment of all these levels of pain must be combined to ensure the effectiveness of chronic pelvic pain treatment. Treatment for chronic pelvic pain includes psychological counseling, physical therapy, medication, nerve blocks, and surgery.

Pelvic venous pain

Dilation of the uterine and ovarian veins is often accompanied by the development of pelvic pain. Its features include onset or worsening after physical exertion, prolonged sitting and standing, and in the middle of the menstrual cycle. It decreases with bioflavonoid treatment and after resting in a horizontal position. Usually, this pain is constant, dull, and aching, almost never completely disappears, and is refractory to analgesic treatment. The presence of varicose veins on the perineum or genitalia should be a signal for you to consult a vascular surgeon or phlebologist.

What are pelvic veins?

It might seem simple—all veins located in the lesser pelvis are pelvic veins. But this is not entirely true. Pelvic veins include the veins of the uterus and appendages (uterine and parametrial veins), the ovarian venous plexus (pampiniform plexus), and the ovarian (gonadal) veins. Gonadal veins are not located in the lesser pelvis, but on the posterior abdominal wall, retroperitoneally; nevertheless, they are classified as pelvic veins. The right gonadal vein empties into the inferior vena cava, while the left gonadal vein drains into the left renal vein, pathology of which can lead to dilation of the left gonadal vein. This pathology is called left renal vein compression syndrome (nutcracker syndrome), when this vessel is compressed between the aorta and the superior mesenteric artery, causing impaired blood outflow through the left renal vein, and the appearance of red blood cells (hematuria) and protein (proteinuria) in the urine. Significant narrowing of this vessel requires surgical treatment. In addition, large venous trunks—the iliac veins—are located in the lesser pelvis. These are paired vessels located on the left and right iliac bones. The external, internal, and common iliac veins are distinguished. The left common iliac vein is crossed by the right common iliac artery, which leads to the development of a significant (treatment-requiring) stenosis (lumen narrowing) of the left common iliac vein in 10–25% of people. The left and right internal iliac veins have tributaries—the obturator, internal pudendal, and inferior gluteal veins—which are interconnected with the veins of the perineum and external genitalia. These tributaries are also called pelvic veins. Thus, in pelvic congestion syndrome, interventions may be required not only on the pelvic veins themselves, but also on the renal and iliac veins.

Normally, blood in the pelvic veins moves from the periphery to the heart, facilitated by the valves present in the veins. When the veins dilate, the valves in them stop holding the blood, and it moves in the opposite direction; this is called reflux. It is precisely the reflux in the pelvic veins that causes the development of pelvic pain syndrome.

How can my doctor diagnose pelvic vein disorders?

Your doctor will carefully study your medical history. Therefore, it is very important to give your doctor a detailed and accurate description of your problem. They will perform a physical examination. Based on this, the doctor will determine what laboratory tests and procedures are needed to find the causes of your pain:

• Bring copies of medical records, including doctor visits, laboratory results, ultrasounds, CT scans, MRIs, or laparoscopies.

• Carefully fill out the questionnaire provided by your doctor. Take your time and try to recall all the details and the order in which they occurred. Filling out the questionnaire can help you remember details you forgot. It is easier to write down personal information that is difficult or awkward to say out loud. Remember, the more information you provide to your doctor, the easier it will be for them to help you.

• Important factors to pay attention to:

 When and how did the pain start?

 What activities worsened/improved it? (This may include sitting, driving, running, cycling, gym workouts)

 Does stress increase the pain?

 Does it change during the day, week, month?

 How does the menstrual cycle affect the pain?

 How does the pain affect sleep?

 How much has the pain worsened since it first appeared?

 Have you noticed abnormal skin hypersensitivity (pain, itching, burning), muscle or joint pain, or lower back pain?

 Do you have pain with urination, frequent urination, constipation, diarrhea, or bladder or bowel problems?

 Do you have pain during sexual intercourse?

 Has the pain affected your emotional state, such as feelings of anxiety or depression?

What did not help?

 What medical or surgical treatments have you received?

 Did they help?

 What did you do to reduce the pain?

What helped?

 What medications have you used in the past?

 What medications are you taking now?

 What do you think is causing the pain?

Duplex ultrasound scanning is the fastest and completely safest method for detecting pelvic vein disorders. It is performed in two ways: through the anterior abdominal wall (transabdominally) and through the vagina (transvaginally). This allows for a comprehensive assessment of the condition of all pelvic veins, renal veins, and iliac veins. If varicose veins or stenosis of the left renal and common iliac veins are detected, additional computed tomography (CT) or magnetic resonance imaging (MRI) must be performed. These methods will help your doctor more accurately assess the condition of the pelvic veins and the significance of the stenosis of the left renal and common iliac veins. When CT and MRI do not allow for a definitive assessment of the severity of changes in the renal and iliac veins, another study is performed: renophlebography with pressure measurement in the left renal vein, or pelvic phlebography. These studies may be supplemented with intravascular ultrasound. After the anatomical features of the structure of your pelvic veins and retroperitoneal veins are clarified, the doctor will decide on the treatment method.

When will the doctor decide how to help me?

Your doctor will consider a number of factors to decide how best to treat your pain. Pain is not always entirely physical; it can also exist in your mind. Pelvic pain may be caused not by a single problem, but by multiple interacting factors. This means that a single treatment will not suffice; it is important to use a multidisciplinary approach. You may need several types of treatment.

It is impossible to say how many individual pain factors contribute to the chronic pain problem. In reality, it does not matter what initially triggered your pain; it may become only a secondary factor while the chronic pain is sustained by secondary factors. Treatment should target all factors, not just the one that seems most important.

How soon will I start feeling better?

It may take a long time before you start feeling better, even if your doctor is trying to provide relief as quickly as possible. The pain has had a lot of time to become severe, and its treatment may take weeks or months to resolve completely. During your treatment, as you gradually get better, try to remain calm, patient, and maintain a positive attitude.

Do I need to take painkillers or other medications?

The choice of treatment depends on the severity of your pelvic pain and the results of ultrasound and radiological examinations. Medications are used when chronic pelvic pain (CPP) occurs against the background of dilation of only the uterine and adnexal veins. In the early stages of treatment, you may be prescribed painkillers. CPP therapy takes some time to start working, and medications will keep you comfortable until the treatment takes effect. However, remember that painkillers are a temporary treatment for symptoms (the pain you feel), whereas the primary treatment aims to eliminate the underlying problem. Painkillers do not fully cure the pain, but make your symptoms more tolerable. Other medications, such as antispasmodics, antidepressants, or local anesthetics, are used for abnormal nerve activity, which, as noted above, is present in many patients with CPP. These are not special painkillers, but specially developed drugs designed to interrupt heightened pain activity. All medications can have side effects, especially opioid analgesics. Your doctor will initially use non-opioid analgesics to prevent potential drug side effects.

The most effective pharmacological treatments for venous CPP are bioflavonoids, which act on the venous wall and improve blood properties. A prerequisite for successful bioflavonoid treatment is a long-term course of medication. Typically, the duration of bioflavonoid intake is 2 months, but in individual cases, your doctor may recommend extending the intake to 3–4 months. Be sure to inform your attending physician about the effect of bioflavonoids on your pelvic pain; this is crucial not only for an accurate assessment of a specific drug's efficacy, but also for understanding whether your pelvic pain is of venous origin, or if other causes of the disease should be sought or a new pelvic vein examination undertaken. Usually, a reduction in CPP occurs after 7–10 days of taking the medication. If this does not happen, you should not stop taking the drug; you must continue its use, as in some cases the effect appears after 1–1.5 months.

You may be advised a combination of medications. Drugs often complement each other and are more effective when used in combination. You can achieve the greatest pain relief by using painkillers and other mood-modulating drugs, such as antidepressants. Taking medications every time you feel pain can make you dependent on the drugs. Take medications at fixed times rather than every time pain occurs for more effective pain control. Your doctor will give you prescriptions for a fixed amount of painkillers and instruct you on how to take a specific dose on a regular schedule at set times.

If you find that over time the medication relieves pain less and less, this indicates that the body is developing tolerance to the painkiller. Talk to your doctor about the effectiveness of your medication. Changing the medication is not something your doctor can easily do based on a phone call.

Some medications that alter pain perception, such as antidepressants or antispasmodics, may also be prescribed.

Will surgery be necessary?

If indicated, the doctor may recommend surgical treatment or an endovascular intervention. This depends on the nature of the changes in the pelvic veins. Dilation of the gonadal, parametrial, and uterine veins is an indication for interventions on the gonadal veins, the positive effect of which in terms of relieving pelvic venous pain is universally recognized. Eliminating the backward flow (reflux) of blood through the gonadal vein leads to a reduction in blood stasis in the uterus and adnexes and the disappearance or significant reduction of CPP. Varicose veins on the uterus and adnexes are never removed; after blood flow through the gonadal veins ceases, the parametrial and uterine veins contract on their own, and blood reflux disappears in them.

Open extraperitoneal resection of the gonadal veins requires general anesthesia and a small (up to 5 cm) incision in the left or right iliac regions. The essence of the surgery is to expose a 10 cm segment and remove a section of the gonadal vein after ligating all tributaries of this vessel. Following this surgery, pelvic pain disappears in 84–100% of patients. In the postoperative period, painkillers may be required due to pain in the surgical area. In addition, antithrombotic agents are prescribed for the prevention of pelvic vein thrombosis as a single subcutaneous injection into the abdomen. Complications after this surgery are extremely rare; pelvic vein thrombosis is detected in 8–10% of patients. Patients are able to move independently and take food 3–4 hours after surgery. Patients may be discharged from the hospital the day after the procedure.

Endoscopic gonadal vein resection is performed under general anesthesia. The essence of the intervention is similar to open resection. The main difference of the endoscopic method is access to the gonadal veins through small, up to 1 cm, skin incisions. Due to lower invasiveness, postoperative pain is mild and often does not require the use of analgesics. Antithrombotic agents are also prescribed after surgery. 3–4 hours after the intervention, patients get out of bed, actively move around, and take food. Patients are discharged from the hospital the next day if there are no complications. The effectiveness of the surgery in reducing or completely eliminating pelvic pain and other symptoms of the disease is 88–100%. Complications of the surgery are rare: pelvic vein thrombosis (10%) and transient intestinal paresis (7%).

After performing surgical interventions on the gonadal veins, you should follow these recommendations:

1. After gonadal vein surgeries, you should maintain a protective regimen, avoid heavy lifting, and refrain from prolonged standing or sitting.

2. You may take a shower 7 days after the surgery; until then, it is advisable to limit yourself to hygiene procedures and keep the postoperative wounds dry.

3. Following the surgery, pelvic congestion symptoms do not disappear immediately; a certain period (from 7 to 14 days) is required, after which the venous outflow from the pelvic organs normalizes and the phenomena of blood stasis in them will disappear.

4. Pelvic congestion syndrome is a chronic condition that requires not only surgical intervention, but also the intake of bioflavonoids. Your doctor will prescribe a course of the medication (at least 2 months) after the surgery. It is necessary to strictly follow the medication regimen.

5. After the cessation of blood flow in the gonadal veins, thrombosis of the pelvic veins may develop. Therefore, to prevent this complication, you will be prescribed antithrombotic agents, which must be used for at least 7 days after the surgery. You can self-administer antithrombotic agents subcutaneously into the abdomen; your attending physician should explain to you how to do this.

6. In some cases, despite the use of antithrombotic agents, pelvic vein thrombosis develops after surgery. In the hospital, you will be prescribed a therapeutic dose of an anticoagulant agent, which you can self-administer subcutaneously at home.

7. In the event of pelvic vein thrombosis, it is necessary to perform an ultrasound examination of the pelvic veins 7–10 days after discharge from the hospital to assess the condition of the pelvic veins and the thrombi within them.

8. Pay attention to the dynamics of changes in pelvic pain and other symptoms of pelvic varicosities that you noted before the surgery. Inform your doctor about your sensations, do not hesitate to report intimate details (presence/absence of pain during and after intercourse) and minor changes in your feelings.

9. In case of fever or significant pain in the surgical area, you must immediately inform your attending physician and seek medical help at the facility where the surgery was performed.

Left renal vein transposition is necessary for patients with pronounced stenosis of the left renal vein, which leads not only to pain in the left half of the abdomen, but also to an increase in venous pressure in the kidney, the appearance of red blood cells (hematuria) and protein (proteinuria) in the urine. During this surgery, a new connection is formed between the left renal vein and the inferior vena cava, thereby eliminating the stenosis of the left renal vein. The efficacy of the surgery in relieving symptoms of the disease is 88–100 %. This is a traumatic surgery and may be complicated by impaired renal function (3 %), suppuration of the postoperative wound (2–5 %), and left renal vein thrombosis.

Left gonadal vein transposition (gonadal-iliac, gonadal-caval shunting) serves as a less invasive method than renal vein transposition for eliminating venous renal hypertension in patients with pronounced stenosis of the left renal vein. The essence of the surgery is the creation of anastomoses between the left gonadal vein and the left common iliac vein (or inferior vena cava). Due to the creation of this bypass pathway for the venous outflow of the left kidney, venous pressure in the kidney decreases, hematuria and proteinuria, as well as abdominal pain, disappear. The efficacy of the surgery is 95–100 %.

After surgical interventions on the left renal vein, you should follow these recommendations:

1. After the surgery, you should adhere to a sparing regimen, avoid lifting heavy objects, and refrain from standing or sitting for long periods.

2. You may take a shower 7 days after the surgery; until then, it is advisable to limit yourself to hygiene procedures and keep the postoperative wounds dry.

3. Following the surgery, abdominal pain, hematuria, and proteinuria do not disappear in the first days after the intervention; a certain period (up to 30 days) is required, after which the venous outflow from the left kidney normalizes and the clinical manifestations of nutcracker syndrome disappear or significantly decrease.

4. Intervention on the left renal or left gonadal vein may be accompanied by the development of left renal vein thrombosis or pelvic vein thrombosis. Therefore, to prevent this complication, you will be prescribed antithrombotic agents, which must be used for at least 30 days after the surgery. You can self-administer antithrombotic agents subcutaneously into the abdomen; your attending physician should explain to you how to do this.

5. In some cases, despite the use of antithrombotic agents, thrombosis of the left renal vein or pelvic veins develops after surgery. In the hospital, you will be prescribed a therapeutic dose of an antithrombotic agent, which you can self-administer subcutaneously at home. The duration of antithrombotic agent use will be determined by your attending physician, but it will be no less than 30 days.

6. In the event of left renal vein thrombosis, treatment must be carried out in a hospital setting, monitoring the functional state of the left kidney and the dynamics of thrombosis. Anticoagulant therapy in prophylactic doses will need to be continued after discharge from the hospital.

7. Pay attention to the dynamics of changes in pelvic pain and other symptoms of nutcracker syndrome that you noted before the surgery. Inform your doctor about your sensations, do not hesitate to report intimate details (presence/absence of pain during and after intercourse) and minor changes in your feelings.

8. In case of fever or significant pain in the surgical area, you must immediately inform your attending physician and seek medical help at the facility where the surgery was performed.

Endovascular embolization of the gonadal veins serves as the least invasive method for eliminating blood reflux through the gonadal veins and is performed under local anesthesia. Using vascular puncture (of the femoral or brachial vein), a special catheter is used to place metal coils (which are the finest nitinol or platinum wires that spontaneously coil inside the vein) or chemical agents (glue, venosclerosing agents for local injections) into the gonadal veins, which overstretch or occlude the vein, stopping blood flow in it. Pain syndrome in the vein puncture area is minimal or absent altogether. Antithrombotic agents are prescribed to prevent pelvic vein thrombosis. Patients can be discharged from the hospital on the day of surgery or the next day. A reduction or complete disappearance of disease symptoms is observed in 60–100 % of patients. This therapeutic procedure has the following inherent complications: coil migration into the pulmonary artery and heart (2 %), coil protrusion (prolapse of the coil through the wall of the gonadal vein, 8 %), post-embolization syndrome (20–54 %), and pelvic vein thrombosis (27 %).

After endovascular occlusion of the gonadal veins, you should follow these recommendations:

1. After the surgery, you should adhere to a sparing regimen, avoid lifting heavy objects, and refrain from standing or sitting for long periods.

2. You may take a shower the day after the surgery, as there are no postoperative wounds.

3. Following the surgery, pelvic congestion symptoms do not disappear immediately; a certain period (from 7 to 14 days) is required, after which the venous outflow from the pelvic organs normalizes and the phenomena of blood stasis in them will disappear.

4. Endovascular intervention on the gonadal veins is often accompanied by the development of post-embolization syndrome (in approximately one-third of patients). This is accompanied by increased pelvic pain, fever, and soreness in the projection of the embolized vein. To relieve these symptoms, you will be prescribed nonsteroidal anti-inflammatory and antirheumatic drugs. Usually, the aforementioned discomfort disappears within 3–7 days.

5. In some patients, a complication of the intervention associated with the prolapse of coil turns through the vein wall may develop. This is called protrusion. In such cases, pain in the area of the occluded vein persists for more than 1 month, and surgical intervention may be required during which the gonadal vein with the coils inside it is removed.

6. In extremely rare cases, embolization coils can migrate from the gonadal vein and end up in the right chambers of the heart and the pulmonary artery. This complication is eliminated using intravascular (endovascular) removal of the coil from the heart or pulmonary artery. In exceptional cases, open surgery (thoracotomy) may be required.

7. Pelvic congestion syndrome is a chronic condition that requires not only surgical intervention, but also the intake of bioflavonoids. Your doctor will prescribe a course of the medication (at least 2 months) after the surgery. It is necessary to strictly follow the medication regimen.

8. After the cessation of blood flow in the gonadal veins, thrombosis of the pelvic veins may develop. Therefore, to prevent this complication, you will be prescribed antithrombotic agents, which must be used for at least 7 days after the surgery. You can self-administer antithrombotic agents subcutaneously into the abdomen; your attending physician should explain to you how to do this.

9. In some cases, despite the use of antithrombotic agents, pelvic vein thrombosis develops after surgery. In the hospital, you will be prescribed a therapeutic dose of an anticoagulant agent, which you can self-administer subcutaneously at home.

10. In the event of pelvic vein thrombosis, it is necessary to perform an ultrasound examination of the pelvic veins 7–10 days after discharge from the hospital to assess the condition of the pelvic veins and the thrombi within them.

11. Pay attention to the dynamics of changes in pelvic pain and other symptoms of pelvic varicosities that you noted before the surgery. Inform your doctor about your sensations, do not hesitate to report intimate details (presence/absence of pain during and after intercourse) and minor changes in your feelings.

Endovascular stenting of the left renal vein serves as an alternative to open left renal vein transposition. By puncturing the femoral or jugular vein, a vessel-expanding metal device is installed via a catheter into the left renal vein, which widens the vessel lumen and restores normal blood flow through the left renal vein.

After performing left renal vein stenting, you should follow these recommendations:

1. After the surgery, you should adhere to a sparing regimen, avoid lifting heavy objects, and refrain from standing or sitting for long periods.

2. You may take a shower the day after the surgery, since there are no postoperative wounds.

3. Following the surgery, abdominal pain, hematuria, and proteinuria do not disappear in the first days after the intervention; a certain period (up to 30 days) is required, after which the venous outflow from the left kidney normalizes and the clinical manifestations of nutcracker syndrome disappear or significantly decrease.

4. Intervention on the left renal vein may be accompanied by the development of left renal vein thrombosis. Therefore, to prevent this complication, you will be prescribed antithrombotic agents, which must be used for at least 30 days after the surgery. You can self-administer antithrombotic agents subcutaneously into the abdomen; your attending physician should explain to you how to do this.

5. In some cases, despite the use of antithrombotic agents, thrombosis of the left renal vein develops after surgery. In the hospital, you will be prescribed a therapeutic dose of an antithrombotic agent, which you can self-administer subcutaneously into the anterior abdominal wall at home. The duration of antithrombotic therapy will be determined by your attending physician, but it will not be less than 30 days.

6. In the event of left renal vein thrombosis, treatment must be carried out in a hospital setting, monitoring the functional state of the left kidney and the dynamics of thrombosis. Anticoagulant therapy in prophylactic doses will need to be continued after discharge from the hospital.

7. A rare complication of left renal vein stenting is stent migration into the right heart chambers, which may require open surgery—thoracotomy.

8. Pay attention to the dynamics of pelvic pain, right-sided flank pain, and other symptoms of the nutcracker syndrome that you experienced before surgery. Inform your doctor about your sensations, do not hesitate to report intimate details (presence/absence of pain during and after sexual intercourse) and minor changes in your condition.

Endovascular stenting of the left common iliac vein is the best way to restore normal blood flow through this vessel in May-Thurner syndrome (compression stenosis of the left common iliac vein). A puncture of the left femoral vein is performed, and a stent is placed through a special catheter into the common iliac vein, which widens the vein and restores normal blood flow through it.

After undergoing iliac vein stenting, you should follow these recommendations:

1. Following iliac vein stenting, you should maintain a gentle regimen, avoid lifting heavy objects, and refrain from prolonged standing or sitting.

2. You may take a shower the day after the surgery, as there are no postoperative wounds.

3. Following the surgery, pelvic congestion symptoms do not disappear immediately; a certain period (from 7 to 14 days) is required, after which the venous outflow from the pelvic organs normalizes and the phenomena of blood stasis in them will disappear.

4. To prevent thrombosis of the stent placed in the vein, you will be prescribed antithrombotic agents in prophylactic dosages. It is extremely critical to take these medications strictly in accordance with the schedule recommended by your attending physician. This will help avoid serious complications.

5. In rare cases, patients develop stent thrombosis after stenting. In this case, you will be prescribed a therapeutic dose of antithrombotic agents for 30 days, followed by a prophylactic dose for 5 months.

6. Another way to treat iliac vein stent thrombosis is endovascular catheter-directed aspiration thrombectomy (removal of the thrombus) followed by thrombolytic and anticoagulant therapy. Your attending physician will provide you with comprehensive information regarding the specifics of endovascular thrombectomy and thrombolysis.

7. In extremely rare cases, the stent may migrate from the iliac veins and enter the right heart chambers. This complication is treated with an open surgery—thoracotomy.

8. Pelvic congestion syndrome combined with May-Thurner syndrome is a chronic condition that requires not only surgical intervention but also the intake of bioflavonoids. In addition to anticoagulant and antiplatelet therapy, your doctor will prescribe a course of bioflavonoids (for at least 2 months) after surgery. It is necessary to strictly follow the medication schedule.

9. Pay attention to the dynamics of changes in pelvic pain and other symptoms of pelvic varicosities that you noted before the surgery. Inform your doctor about your sensations, do not hesitate to report intimate details (presence/absence of pain during and after intercourse) and minor changes in your feelings.

Removal of vulvar veins (perineal phlebectomy) serves as an effective method for eliminating vulvar and perineal varicose veins. The surgery is performed under spinal anesthesia; varicose veins are exposed and removed through small (up to 1 cm) incisions.

After undergoing perineal phlebectomy, you should follow these recommendations:

1. After the surgery, you should adhere to a sparing regimen, avoid lifting heavy objects, and refrain from standing or sitting for long periods.

2. You may take a shower 7 days after the surgery; until then, the postoperative wounds must not be exposed to water.

3. In the postoperative period, you may experience moderate pain in the surgical area; if necessary, you can take painkillers (analgin).

4. In rare cases, a yellowish fluid (so-called lymphorrhea) may ooze from the postoperative wounds, which does not require special treatment and resolves spontaneously within 7–10 days.

5. After surgery, you may notice swelling in the intervention area. This is due to surgical trauma and resolves spontaneously within 3–5 days after surgery.

6. In the postoperative period, a course of bioflavonoids will be recommended (usually for 2 months). This is necessary for your prompt rehabilitation and to improve venous outflow from the pelvic organs.

7. In case of fever or significant pain in the surgical area, you must immediately inform your attending physician and seek medical help at the facility where the surgery was performed.

Scleroobliteration of the external genitalia and perineal veins serves as an alternative to perineal phlebectomy. It can be used when vulvar and perineal veins are dilated to no more than 5 mm. The essence of the intervention is the injection of a drug into the varicose veins that causes destruction of the inner layer of the vein, subsequently leading to its obliteration (closure).

Even though this is a minimally invasive outpatient procedure, your doctor needs information about your health status, which requires a standard general clinical examination.

Patients scheduled for scleroobliteration of vulvar/perineal veins are advised to:

1. Inform the attending physician about any allergic reactions to medications, if any.

2. Inform the attending physician about heart conditions, particularly the presence of a patent foramen ovale.

3. During the sclerotherapy session, minor pain is possible at the injection site.

4. After sclerotherapy, the patient must perform manual compression of the intervention area for 5 minutes in a horizontal position using a gauze pad provided by the doctor.

5. There are no restrictions on physical activity or work routine after vulvar vein sclerotherapy.

6. If body temperature rises to 38°C or sharp pain occurs in the scleroobliteration area, you must immediately inform your attending physician and seek medical care at the facility where the perineal vein sclerotherapy was performed.

7. To increase the efficacy of this treatment method, a course of bioflavonoids is recommended, starting 1–2 weeks before the first sclerotherapy session.

Appendix G. Assessment Scales, Questionnaires, and Other Evaluation Tools

Appendix G1. Visual Analogue Scale

Russian title: Visual Analog Scale (VAS).

Original title: Visual Analog Scale for Pain, VAS.

Source (official developer website, validation publication): Hawker GA, Mian S, Kendzerska T, French M. Measures of adult pain: Visual Analog Scale for Pain (VAS Pain), Numeric Rating Scale for Pain (NRS Pain), McGill Pain Questionnaire (MPQ), Short-Form McGill Pain Questionnaire (SF-MPQ), Chronic Pain Grade Scale (CPGS), Short Form-36 Bodily Pain Scale (SF-36 BPS), and Measure of Intermittent and Constant Osteoarthritis Pain (ICOAP). Arthritis Care Res (Hoboken). 2011; 63 Suppl 11: S 240–252.

Type (underline):

- assessment scale

- score

- questionnaire

- other (specify):

Purpose: assessment of pain severity.

Content (template): The VAS is a straight line 10 cm in length. The distance between the left end of the line and the user's mark is measured in millimeters. The patient is asked to make a mark on the line corresponding to the intensity of pain they are experiencing.

Key (interpretation): Based on the score distribution, the following classification is recommended: no pain – 0 points (0–4 mm); mild pain – 1–3 points (5–44 mm), moderate pain – 4–6 points (45–74 mm), 7–10 points – severe pain (75–100 mm).

Notes: none.

Appendix G2. Numerical Rating Scale

Original name: Numerical Rating Scale (NRS).

Source (official developer website, validation publication): Karcioglu O, Topacoglu H, Dikme O. A systematic review of the pain scales in adults: Which to use? American Journal of Emergency Medicine. 2018; 36(4):707-714.

Type (underline):

- assessment scale

- score

- questionnaire

- other (specify):

Purpose: assessment of pain severity.

Content (template): The NRS is a continuous scale in the form of a horizontal or vertical line 10 cm (100 mm) long with two endpoints: "no pain" and "worst pain imaginable". The patient is asked to make a mark on this line corresponding to the intensity of pain they are currently experiencing. The distance between the start of the line ("no pain") and the patient's mark is measured in centimeters and rounded to the nearest whole number. Each centimeter (10 mm) on the scale corresponds to 1 point.

Key (interpretation): no pain – 0 points (0–4 mm), mild pain – 1–4 points (5–44 mm), moderate pain – 5–7 points (45–74 mm), severe pain – more than 7 points (75–100 mm).

Notes: none.

Appendix G3. Von Korff Chronic Pain Grade Scale

Russian title: Von Korff Chronic Pain Grade Scale.

Original title: Chronic pain grade questionnaire, CPGQ.

Source (official developer website, validation publication): Von Korff M, Ormel J, Keefe FJ, Dworkin SF. Grading the severity of chronic pain. Pain. 1992;50(2):133-149.

Type (underline):

- assessment scale

- score

- questionnaire

- other (specify):

Purpose: assessment of pain severity and patient social disability.

Content (template): used to assess chronic pain syndrome and its impact on patients' social activity.

1. How would you rate the pain you are currently experiencing on a 10-point scale?

2. How would you rate the most intense pain you have experienced over the past 6 months on a 10-point scale?

3. How would you rate the average pain intensity over the past 6 months (i.e., the intensity of your usual pain)?

4. Approximately how many days over the past 6 months have you been unable to carry out your usual activities (at work, school, or home) due to pain?

___________________________________________________________________________

How has pain affected your daily activity over the past 6 months, rated on a scale from 0 to 10?

5. How has pain affected your ability to participate in recreational, social, and family activities over the past 6 months?

6. How has pain affected your ability to work (including housework) over the past 6 months?

Evaluation of Von Korff questionnaire results

Pain intensity score: mean score from 0 to 100 based on answers to questions 1, 2, and 3.

Mean score = (current pain intensity + worst pain + average pain intensity) × 10 / 3

Disability score: mean score from 0 to 100 based on answers to questions 5, 6, and 7.

Mean score = (daily activity + social activity + work ability) × 10 / 3

Disability level assessment: the sum of the disability degree and days of disability (in points) is calculated using the table.

Assessment of social disability level using the Von Korff scale

Classification of chronic pain by intensity and disability level using the Von Korff scale

Key (interpretation): presented in the table (see above).

Notes: a feature of the scale is the account of pain duration and strength, as well as the impact of pain on daily activities, rest, and work capacity over the past month.