What is the most appropriate investigation for a patient with intermittent claudication, decreased sensation, and painful left leg while walking, relieved with rest, and absent distal pulses?

Appropriate Investigation for Intermittent Claudication with Absent Distal Pulses

For this patient with classic intermittent claudication and absent distal pulses bilaterally, MR angiography (MRA) with contrast or CT angiography (CTA) are the most appropriate initial investigations, with MRA slightly preferred (both rated 8/9) to define the extent of disease and plan potential revascularization. 1

Clinical Context

This patient presents with:

• Classic intermittent claudication (pain with walking, relieved by rest) 1
• Palpable femoral and popliteal pulses bilaterally (indicating proximal vessel patency) 1
• Absent distal pulses bilaterally (suggesting infrainguinal disease) 1
• Decreased sensation (indicating more severe ischemia than simple claudication) 1

The bilateral absence of distal pulses with preserved proximal pulses localizes disease to the tibial/peroneal vessels, requiring detailed imaging of the entire lower extremity arterial tree. 1

Recommended Imaging Algorithm

First-Line Imaging Options (Both Highly Appropriate):

MRA lower extremity with IV contrast receives the highest rating (8/9) from the American College of Radiology for vascular claudication assessment for revascularization. 1 This modality:

• Provides excellent anatomic detail without radiation exposure 1
• Allows comprehensive evaluation from aortoiliac vessels through pedal arteries 1
• Has no nephrotoxicity risk from iodinated contrast 1

CTA lower extremity with IV contrast is equally rated (8/9) and is specifically noted as "the test of choice in patients who cannot have MRA." 1 CTA advantages include:

• Faster acquisition time than MRA 1
• Superior visualization in patients with calcified vessels 1
• Wider availability in most centers 1

Why Other Options Are Less Appropriate:

Vascular ultrasound duplex Doppler (Option B) receives a lower rating (7/9) and is specifically designated as "useful in patients with contrast allergy or renal dysfunction" rather than as first-line imaging. 1 While ultrasound is non-invasive and has no radiation, it has significant limitations:

• Operator-dependent with variable accuracy 2
• Cannot adequately visualize the entire arterial tree in one examination 1
• Difficulty evaluating deep vessels and heavily calcified arteries 2
• Time-consuming for complete lower extremity assessment 1

Conventional catheter angiography (Option C) receives a rating of only 7/9 and carries an important caveat: "This procedure is indicated only if intervention is planned." 1 The American College of Radiology explicitly states catheter angiography "should be performed only at the time of endovascular therapy." 1 This is not appropriate as an initial diagnostic test because:

• It is invasive with procedural risks 1
• Requires arterial access with potential complications 1
• Exposes patient to iodinated contrast and radiation 1
• Should be reserved for simultaneous diagnosis and treatment 1

Important Clinical Caveats

The presence of decreased sensation is concerning and may indicate more severe ischemia than typical claudication alone. 1 The ACC/AHA guidelines emphasize that patients with intermittent claudication should first undergo measurement of ankle-brachial index (ABI) to confirm the diagnosis and assess severity. 1 However, arterial imaging with MRA or CTA is indicated when:

• Revascularization is being considered 1
• The patient has significant functional impairment 1
• There are neurologic symptoms suggesting more severe disease 1

Bilateral disease pattern matters: The finding of bilateral absent distal pulses with preserved proximal pulses suggests multilevel infrainguinal disease that will require detailed anatomic mapping for treatment planning. 1

Renal function should be assessed before contrast-enhanced imaging. If the patient has severe chronic kidney disease (eGFR <30 mL/min), MRA without contrast (rated 5/9) becomes more appropriate, though less optimal. 1

Answer to Multiple Choice Question

The correct answer is D - Magnetic Resonance Angiography, though CT angiography (Option A) would be equally appropriate. Both receive the highest appropriateness ratings (8/9) from the American College of Radiology for assessment of vascular claudication when revascularization is being considered. 1

Vascular ultrasound (Option B) is rated lower (7/9) and reserved for patients with contraindications to contrast. 1 Conventional angiography (Option C) should only be performed at the time of planned intervention, not as an initial diagnostic test. 1