What is the diagnostic approach, management, complications, differential diagnosis, and prognosis of Takayasu arteritis?

Takayasu Arteritis: Diagnostic Approach, Management, Complications, Differential Diagnosis, and Prognosis

Takayasu arteritis is an idiopathic vasculitis of elastic arteries primarily affecting the aorta and its major branches, requiring aggressive immunosuppressive therapy with corticosteroids as first-line treatment and close monitoring with both clinical assessment and vascular imaging. 1, 2

Definition and Epidemiology

• Takayasu arteritis (TAK) is a T-cell-mediated panarteritis that proceeds from adventitial vasa vasorum involvement inward, affecting the aorta and its major branches 2
• The disease disproportionately affects women (10:1 female-to-male ratio) and typically presents in the third decade of life 3
• Two distinct distribution patterns exist: Japanese type (affecting thoracic aorta and great vessels) and Indian type (affecting abdominal aorta and renal arteries) 1, 3

Diagnostic Approach

Clinical Presentation

• The disease typically develops in two phases:
  • Acute phase with constitutional symptoms (fever, fatigue, weight loss)
  • Chronic phase with symptoms related to arterial involvement (claudication, decreased pulses, bruits) 2
• The 1990 American College of Rheumatology diagnostic criteria include:
  • Age of onset <40 years
  • Limb claudication
  • Diminished brachial artery pulse
  • Subclavian/aortic bruit
  • BP difference >10 mmHg between arms
  • Angiographic evidence of aorta/branch vessel stenosis 2, 3
• When 3 of these criteria are present, the sensitivity is 90.5% and specificity is 97.8% 1

Laboratory Testing

• No specific diagnostic laboratory tests, biomarkers, or autoantibodies exist 4
• Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) should be measured to establish baseline inflammatory markers 3
• These markers help monitor disease activity but may not always correlate with vascular inflammation 1, 4

Imaging

• Initial evaluation should include thoracic aorta and branch vessel computed tomographic imaging or magnetic resonance imaging 1, 3
• Noninvasive imaging (CT angiography, MR angiography, or FDG-PET) is preferred over catheter-based dye angiography 1
• Imaging findings suggestive of active disease include:
  • Vascular edema
  • Contrast enhancement
  • Increased wall thickness
  • New stenosis 1
• Regular imaging is recommended even during clinical remission as vascular changes can occur when disease appears clinically quiescent 1

Management

Initial Treatment

• High-dose corticosteroids (prednisone 40-60 mg daily) are the cornerstone of initial therapy 1, 3
• Add a non-glucocorticoid immunosuppressive agent early in treatment for steroid-sparing effects 1, 3
• Options include:
  • Methotrexate (20-25 mg/week) 1, 3
  • Azathioprine (2 mg/kg/day) 1, 3
  • Tumor necrosis factor inhibitors 1, 3
  • Tocilizumab (IL-6 inhibitor) as a second-line agent 1, 3

Monitoring Disease Activity

• Evaluate treatment success periodically with physical examination and inflammatory markers (ESR/CRP) 1
• Regularly scheduled noninvasive imaging in addition to routine clinical assessment is recommended 1
• The Indian Takayasu Clinical Activity Score (ITAS2010) may be helpful for assessing disease activity 4

Surgical and Endovascular Interventions

• Elective revascularization should be delayed until the acute inflammatory state is treated and quiescent 1
• Indications for intervention include:
  • Symptomatic organ ischemia
  • Life-threatening aneurysm formation 5
• Open surgery offers enhanced duration of arterial patency 5
• For endovascular intervention, primary angioplasty without stenting is preferred, with stenting reserved for primary or secondary angioplasty failures 5
• Long-segment stenosis with extensive periarterial fibrosis requires surgical bypass 6

Complications

• Arterial stenosis (occurring in 53% of patients) 2
• Aneurysm formation (23-32% of patients) 2
• Hypertension due to renal artery involvement 2
• Pulmonary thrombosis 7
• Aortic regurgitation 7
• Congestive heart failure 7
• Cerebrovascular events 7
• Vision degeneration or blindness 7
• Hearing problems 7

Differential Diagnosis

• Giant cell arteritis (typically affects older patients and different vascular territories) 1
• Behçet disease (involves both arteries and veins, causing venous thrombophlebitis) 2
• Atherosclerosis 8
• Fibromuscular dysplasia 8
• Congenital vascular anomalies 8
• Other large vessel vasculitides 8

Prognosis

• Prognosis is improving with lower mortality rates in recent years 4
• Factors contributing to improved outcomes include:
  • More effective medical treatments
  • Appropriate use of endovascular interventions 4
  • Earlier diagnosis 6
• Long-term monitoring is essential for all patients with TAK 1
• Patients with apparent clinical remission but with signs of inflammation in new vascular territories on imaging should receive intensified immunosuppressive therapy 1

Common Pitfalls and Caveats

• Delay in diagnosis is common due to nonspecific initial symptoms 4, 7
• Discrepancies may exist between systemic inflammatory markers and actual vascular wall inflammation 4
• Surgical or endovascular interventions performed during active disease have poorer outcomes 5, 6
• Reliance solely on inflammatory markers for disease monitoring is inadequate; clinical assessment and imaging are essential 1, 4