What type of ultrasound do you order for a patient presenting with claudication?

Duplex Ultrasound of the Lower Extremities

For a patient presenting with claudication, order a duplex ultrasound of the lower extremities if you are considering revascularization. 1

Initial Diagnostic Approach

Before ordering any imaging, establish the diagnosis of peripheral artery disease (PAD) with physiological testing:

• Obtain a resting ankle-brachial index (ABI) as the initial diagnostic test—this is sufficient to confirm PAD and initiate guideline-directed medical therapy without any imaging 1
• An ABI ≤0.90 confirms PAD and establishes the diagnosis of claudication 1
• If the resting ABI is normal (1.00-1.40) or borderline (0.91-0.99) but claudication symptoms persist, perform exercise treadmill ABI testing to unmask PAD 1

When to Order Duplex Ultrasound

Duplex ultrasound is indicated only when revascularization is being considered, not for routine diagnosis 1:

• Order duplex ultrasound for patients with lifestyle-limiting claudication who have failed guideline-directed medical therapy (including structured exercise programs and optimal medical management) 1
• The purpose is to determine the anatomic location and severity of stenosis to plan a potential revascularization strategy 1
• Duplex ultrasound identifies stenotic lesions, assesses vascular access sites, and determines feasibility of endovascular or surgical intervention 1

Critical Pitfall to Avoid

Do not order duplex ultrasound, CTA, or MRA for anatomic assessment in patients with confirmed PAD if revascularization is not being considered—this is explicitly contraindicated (Class III: Harm recommendation) 1. These imaging studies confer procedural risk without clinical benefit if you're only managing the patient medically 1.

Alternative Imaging Options

If duplex ultrasound is inadequate or unavailable, alternative anatomic imaging includes 1:

• Computed tomography angiography (CTA) of the lower extremities—provides excellent spatial resolution but requires iodinated contrast and radiation exposure 1
• Magnetic resonance angiography (MRA)—avoids radiation but requires gadolinium contrast (contraindicated in severe renal dysfunction due to nephrogenic systemic sclerosis risk) 1

The choice between duplex ultrasound, CTA, and MRA should be individualized based on renal function, contrast allergy history, local expertise, and anatomic factors 1.

Duplex Ultrasound Performance Characteristics

Duplex ultrasound demonstrates 2, 3:

• Very good to good agreement with digital subtraction angiography (the gold standard) in most arterial segments 2
• Better performance in supragenicular arteries (above the knee) compared to infragenicular segments 2
• Sensitivity of 79.7% and specificity of 79.2% for detecting lesions ≥70% stenosis 3
• Some limitation exists in estimating stenosis severity below the knee joint 3

Additional Screening Consideration

Consider ordering a screening duplex ultrasound for abdominal aortic aneurysm (AAA) in patients with symptomatic PAD, as the prevalence of AAA is significantly higher in this population (Class IIa recommendation) 1.