What is the approach to investigating and managing Takayasu arteritis?

Investigation and Management of Takayasu Arteritis

For patients with suspected or confirmed Takayasu arteritis, use noninvasive vascular imaging (CT angiography, MR angiography, or FDG-PET) combined with clinical assessment and inflammatory markers for diagnosis and monitoring, with regularly scheduled imaging every 3-6 months during active disease. 1

Initial Diagnostic Workup

Clinical Assessment

• Look specifically for: diminished or absent peripheral pulses, blood pressure discrepancy >10 mmHg between arms, and vascular bruits over subclavian arteries or aorta 2
• Measure inflammatory markers (ESR/CRP), though recognize these are elevated in only 50% of cases and are imperfect indicators of disease activity 1, 3

Imaging Strategy

• Perform noninvasive imaging as first-line: CT angiography (most commonly used for diagnosis at 58.8%), MR angiography (preferred for follow-up at 62.3%), or FDG-PET 1, 4
• These modalities are superior to catheter angiography because they provide information about vascular wall inflammation, not just luminal changes 1
• Catheter angiography should be reserved for determining central blood pressures, surgical planning, or when noninvasive modalities are inadequate 1

Key Imaging Findings

• Look for: arterial stenosis (most common at 53%), aneurysm formation (23-32%), vascular wall thickening, contrast enhancement, and vascular edema on MR/CT angiography 1, 2
• On FDG-PET: supraphysiologic FDG uptake in arterial walls indicates active disease 1
• Most commonly affected vessels: abdominal aorta (20%), renal arteries (18.7%), and subclavian arteries (14.3%) 3

Ongoing Monitoring Protocol

Clinical Monitoring

• Strongly recommend long-term clinical monitoring even in apparent remission, given minimal risks and potential catastrophic outcomes without monitoring 1
• Monitor: pulse examination, blood pressure in all extremities, vascular bruits, and symptoms of organ ischemia 2
• Add inflammatory markers (ESR/CRP) to clinical assessments, though increases alone should not trigger treatment escalation 1

Imaging Surveillance

• Schedule regular noninvasive imaging in addition to clinical assessment, as vascular changes can occur when disease appears clinically quiescent 1
• Imaging intervals: every 3-6 months during early/active disease, with longer intervals for established quiescent disease 1
• MR angiography is preferred for follow-up over CT angiography to minimize radiation exposure 4, 5

Management Decisions Based on Findings

When to Escalate Immunosuppression

• New arterial stenosis or vessel wall thickening in new territories on imaging warrants immunosuppressive therapy, even if clinically asymptomatic 1
• Active disease findings include: vascular edema, contrast enhancement, increased wall thickness on MR/CT angiography, or supraphysiologic FDG uptake on PET 1
• Critical caveat: Review all imaging findings with a radiologist before therapeutic decisions, as abnormalities are not always specific to vascular inflammation 1

When NOT to Escalate Treatment

• Do NOT escalate therapy for: isolated increases in inflammatory markers without clinical or imaging evidence of active disease 1
• Do NOT escalate for: asymptomatic progression of previously identified vascular lesions without evidence of inflammation, as this may represent "healing" rather than active disease 1
• Instead: increase frequency of clinical and radiographic assessments 1

Surgical Intervention Timing

• Delay surgical intervention until disease is quiescent whenever possible, as observational studies show improved outcomes 1
• Exceptions requiring immediate surgery: coronary artery involvement, impending/progressive tissue or organ infarction, stroke, loss of limb viability, or myocardial ischemia 1
• For renovascular hypertension: prefer medical management (antihypertensives plus immunosuppression) over surgical intervention unless hypertension is refractory or renal function is worsening 1

Common Pitfalls to Avoid

• Do not rely solely on inflammatory markers for disease activity assessment, as they can be nonspecific and normal in active disease 1
• Do not assume clinical remission means imaging stability—30% of patients show radiological progression at one year despite treatment 4
• Do not perform surgery during active inflammation unless life- or organ-threatening, as outcomes are worse 1
• Do not use catheter angiography as routine monitoring, as it only shows luminal changes and misses wall inflammation 1