What is Takayasu arteritis?

Takayasu Arteritis

Takayasu arteritis is an idiopathic, inflammatory, granulomatous vasculitis primarily affecting the aorta and its main branches, typically occurring in young individuals under 40 years of age, with a predilection for women. 1, 2

Definition and Pathophysiology

• Takayasu arteritis is defined as a T-cell-mediated panarteritis that progresses from the adventitial vasa vasorum inward, leading to either destruction causing aneurysms or fibrosis resulting in stenosis of affected arteries 2
• It is classified as a large vessel vasculitis (LVV) that predominantly affects the aorta, its major branches, and pulmonary arteries 1
• The inflammatory process can lead to stenosis, occlusion, dilation, or aneurysm formation in the arterial wall 2

Epidemiology

• Takayasu arteritis typically affects young individuals under 40 years of age, with a strong female predominance 1
• The disease has been reported worldwide but shows characteristic heterogeneity depending on ethnicity and geographical location 3
• The Indian type of Takayasu arteritis primarily affects the abdominal aorta and renal arteries 2

Clinical Presentation

• The disease typically develops in two phases 2:
  • An acute phase with constitutional symptoms (fever, weight loss, night sweats, malaise)
  • A chronic phase with symptoms related to arterial involvement
• Common clinical findings include:
  • Diminished or absent peripheral pulses (a hallmark finding) 2
  • Blood pressure discrepancy >10 mmHg between arms 2
  • Vascular bruits over subclavian arteries or aorta 2
  • Limb claudication due to reduced blood flow 4
  • Hypertension, often due to renal artery involvement 2
• Complications include:
  • Arterial stenosis (occurs in 53% of patients) 1, 2
  • Aneurysm formation (23-32% of patients) 1, 2
  • Cerebral ischemia, which can be severe and debilitating 5

Diagnosis

• Angiographic evidence of aorta or branch vessel stenosis is a key criterion for diagnosing Takayasu arteritis 2
• Modern imaging modalities have largely replaced conventional angiography for initial diagnosis 6, 7:
  • MR Angiography (MRA) is preferred due to less contrast load/radiation 7
  • CT Angiography (CTA) can provide detailed vascular imaging 2
  • 18F-FDG-PET is particularly useful in patients with no vascular symptoms, fever of unknown origin, or unexplained acute-phase response 2, 7
  • Ultrasound is useful for carotid assessment but less reliable for deeper vessels 7
• Laboratory findings often include elevated inflammatory markers:
  • Elevated erythrocyte sedimentation rate (ESR)
  • Elevated C-reactive protein (CRP) 5

Differential Diagnosis

• Giant cell arteritis (typically affects older patients >50 years) 1, 2
• Fibromuscular dysplasia 2
• Aortic coarctation 2
• Other large vessel vasculitides 2

Treatment

• Initial therapy consists of high-dose oral corticosteroids:
  • Prednisone 40-60 mg daily to lower ESR or CRP to normal 1, 2
  • Treatment typically required for 1-2 years 1
  • Nearly half of patients relapse during tapering 1
• Second-line immunosuppressive agents for steroid-sparing or refractory disease:
  • Methotrexate (20-25 mg/week) 2
  • Azathioprine (2 mg/kg/day) 1, 2
  • TNF inhibitors for refractory cases 2, 3
  • Tocilizumab has shown promise in resistant cases 6
• Adjunctive therapy:
  • Low-dose aspirin to prevent ischemic events 2

Vascular Interventions

• Revascularization should be delayed until the acute inflammatory state is treated and quiescent 1, 2
• Indications for intervention include:
  • Secondary organ vascular insufficiency
  • Risk of aneurysm rupture 1
• Intervention options:
  • Endovascular procedures (balloon angioplasty or stent placement) for critical stenosis or aneurysm 2
  • Surgical bypass grafting for long-segment stenosis 2
• Cautions with intervention:
  • Higher risk of graft failure with active local inflammation 1
  • 12% incidence of anastomotic aneurysms over 2 decades of follow-up 1

Monitoring and Prognosis

• Regular clinical assessment and measurement of inflammatory markers (ESR/CRP) are essential 2
• Periodic imaging with MRI or CT to assess disease activity and detect complications 2
• Disease assessment tools:
  • Indian Takayasu Arteritis Score (ITAS2010) aims to better quantify disease activity 6, 7
  • Color-Doppler ultrasonography score (CDUS) 6
• Prognosis has improved in recent years with lower mortality, though substantial vascular damage may still occur even in early cases 6, 7