Endovascular treatment of deep vein thrombosis

Indications and Imaging Evaluation

Today, interventional radiology is not used to treat isolated femoropopliteal segment thrombosis, as this does not reduce the incidence of post-thrombotic syndrome. The primary target for endovascular surgeons is ileofemoral thrombosis and inferior vena cava lesions.

Comprehensive imaging must be performed prior to the intervention:

• Ultrasound helps assess the patency of the venous bed of the lower extremities and select the optimal puncture site.
• CT or MR venography visualizes the iliac veins and IVC, and also rules out external vessel compression by tumors or other pelvic and abdominal masses.
• Intravascular ultrasound (IVUS) is used directly in the operating room to assess residual venous lumen and provide precise control during stent placement.

Methods of Blood Flow Restoration

The procedure begins by passing a hydrophilic guidewire (0.035 inch) through the thrombotic masses and performing venography to assess the extent of the lesion.

There are two main approaches to thrombus removal:

1. Catheter-directed thrombolysis (CDT). A catheter is placed into the thickness of the thrombus, through which a thrombolytic agent is continuously infused. This is a prolonged process taking up to three days.
2. Pharmacomechanical thrombectomy. A combination of mechanical thrombus disruption and local administration of a thrombolytic. This method allows the vein to be cleared significantly faster, fitting into a single intervention.

Once the lumen is cleared, large-diameter self-expanding metal stents are placed to prevent the walls from collapsing again. The patient is discharged with a recommendation to wear compression hosiery and take oral anticoagulants. Treatment outcomes are regularly monitored using duplex scanning.

Superior Vena Cava (SVC) Syndrome and Upper Extremity Pathology

Superior vena cava obstruction (SVCO) is most commonly (in 90% of cases) caused by malignant tumors such as lung cancer or lymphoma. Patients complain of facial and neck edema, dyspnea, and headache.

The baseline treatment for SVC syndrome is chemo- and radiation therapy. However, if these are contraindicated, ineffective, or in case of recurrence, endovascular recanalization is indicated:

• A large uncovered self-expanding stent is placed in the stenosis zone (to prevent its migration into the right atrium).
• To prevent a fatal SVC rupture, post-dilatation (expanding the stent from the inside) is performed very carefully using small-diameter balloons (8–10 mm).

In the upper extremities, thrombosis often occurs in Paget-Schroetter syndrome (compression of the subclavian vein by anatomical structures) or against the background of dialysis fistulas. In Paget-Schroetter syndrome, thrombolysis is performed first, followed by surgical resection of the first rib, and only then angioplasty of the residual stenosis. In fistulas, angioplasty is technically successful, but due to high system pressure, stenoses frequently recur.

Inferior Vena Cava Filter Placement

IVC filters are trap-like devices that protect against fatal pulmonary embolism (PE). Their routine use is not justified. There are strict indications for their implantation: confirmed PE or proximal DVT in situations where anticoagulants are strictly contraindicated or ineffective.

Filters can be permanent or retrievable. Installation requires preliminary cavography to measure the IVC and localize the renal veins.

• Ideal position: below the renal veins (infrarenal), with the apex of the device located at or just below the level of the renal vein orifices.
• Suprarenal placement: required if the thrombus has already spread above the renal veins, in pregnant women (to avoid IVC compression by the uterus), in gonadal vein thrombosis, or in developmental anomalies (e.g., duplicated IVC).

Retrievable filters are removed endovascularly, optimally via access in the right internal jugular vein.

Intervention Complications

Complications are divided into minor (resolving spontaneously, e.g., small hematomas or mild contrast reactions) and major ones requiring separate treatment.

Major complications (occurring in about 1% of cases) include:

• Vessel rupture or pseudoaneurysm formation at the puncture site.
• Major bleeding.
• Distal embolization by thrombus fragments.
• Vessel wall dissection and stent migration.
• Severe allergic or toxic reactions to the contrast agent.

It is important to remember that the use of thrombolytics dramatically increases the likelihood of hemorrhagic complications—bleeding, predominantly in the puncture zone, is observed in almost a third of patients.

Class and exam questions

What else to study on this topic

• Specifics of the surgical technique for first rib resection in Paget-Schroetter syndrome.
• Algorithms for ultrasound duplex scanning after deep vein stenting.
• Regimens for conservative management and anticoagulant therapy after discharge.
• Criteria for choosing between permanent and retrievable IVC filters depending on the clinical situation.

Other topics in the "Interventional radiology" section

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.