Pathogenesis and anatomical classification
The disease runs in two phases: acute (with systemic inflammation) and chronic. The clinical picture strictly follows hemodynamic laws—tissues are deprived of oxygen distal to the site of stenosis or occlusion. Ischemic manifestations develop gradually, months or years after the onset of inflammation.
Depending on the lesion zone revealed on angiography, five types of nonspecific aortoarteritis are distinguished:
- Type I: isolated involvement of the aortic arch branches only (the aorta itself is intact).
- Type II: involvement of the ascending aorta and its arch (IIa). If the pathology also extends to the descending thoracic part, it is subtype IIb.
- Type III: involvement of the descending aorta (thoracic and abdominal segments) with potential involvement of the renal arteries.
- Type IV: the pathological process is limited to the abdominal aorta and/or renal arteries.
- Type V (mixed): total involvement of the vascular bed from the arch to the abdominal segment (combination of types IIb and IV).
Clinical syndromes
In the acute phase, a general inflammatory syndrome is observed: fever, severe fatigue, muscle pain upon exertion. A unique symptom is local tenderness over the projection of the affected artery.
As occlusions develop, topical syndromes emerge:
- Extremity involvement: intermittent claudication syndrome (claudicatio intermittens), subjective discomfort, and pain along the vessels. The main objective sign is the disappearance of the pulse and a drop in blood pressure in the affected limb.
- Cerebroischemic syndrome: occurs when the carotid arteries narrow. It manifests as headaches, fainting (syncope), and vision reduction due to retinal hypoxia.
- Abdominal syndrome: the chronic course causes "abdominal angina" (angina abdominalis). Sharp abdominal pain indicates a life-threatening complication—formation and dissection of an abdominal aortic aneurysm.
- Renovascular syndrome: stenosis of the renal arteries triggers severe arterial hypertension.
Diagnostic Principles
The main problem of the disease is late diagnosis (diagnosis is often established 1–6 years later, when obliteration is already irreversible).
Physical examination requires mandatory palpation of the pulse at symmetric points and blood pressure measurement on all four extremities. Normally, blood pressure in the legs should be 15–20 mmHg higher than in the arms. In aortoarteritis, this physiological gradient disappears, and the systolic blood pressure difference between the right and left arms may exceed 10 mmHg.
Ultrasonography (duplex scanning), CT, and aortography (the main imaging method) are used for verification. For example, renal ultrasound clearly demonstrates asymmetry, organ shrinkage, and a sharp depletion of the vascular pattern on the affected side (in power Doppler mode).
Treatment Management
Basic conservative therapy consists of early and combined immunosuppression.
- Drug therapy: starts with the simultaneous administration of glucocorticoids (prednisolone in high induction doses for 1.5–2 months) and cytostatics (methotrexate). In severe, manifest cases, the regimen is augmented with cyclophosphamide or biologic agents (TNF-α inhibitors).
- Concomitant therapy: antiplatelet agents and angioprotectors are used to improve microcirculation, alongside antihypertensive medications. Etiotropic drugs (antibiotics, anti-tuberculosis drugs, immunoglobulins) are indicated only when an infectious agent's role in the exacerbation is proven.
- Surgical treatment: vascular prosthetics or stenting are performed according to strict indications for critical hemodynamic disorders. These include narrowing of the carotid arteries by more than 70%, renovascular hypertension, subtotal stenosis of other main trunks, and dissecting aneurysm.
Remember "pulseless disease": to avoid missing nonspecific aortoarteritis, blood pressure must be measured on all four extremities. A difference in the arms >10 mmHg or the disappearance of the physiological gradient between the arms and legs is a reason to urgently order vascular ultrasound.
Class and exam questions
What determines the unfavorable prognosis in Takayasu arteritis?
The most unfavorable factor is the involvement of the renal arteries. Renovascular hypertension becomes a predictor for the development of chronic kidney disease (CKD).
Why does blood pressure increase in Takayasu arteritis?
Most often, hypertension occurs due to renal artery stenosis. Less frequently, the cause is coarctation syndrome or cerebral circulation disorders during ischemia of the brachiocephalic trunk.
What should Takayasu arteritis be differentiated from at the stage of vascular occlusions?
In the advanced stage, when pulse asymmetry and aortic deformation are already present according to instrumental studies, the main task is to exclude congenital pathology of the great vessels and aorta.
What else to study on this topic
- Pathogenesis of intermittent claudication in stenoses of major arteries.
- Features of the ultrasound picture (B-mode and Doppler) in ischemic nephropathy.
- Algorithm for tapering prednisolone in the maintenance phase of Takayasu arteritis therapy.
- Indications for the use of biologic agents (infliximab, etanercept) in refractory cases.
- Differential diagnosis of the initial period of Takayasu arteritis with infective endocarditis.
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