What is the recommended workup for a patient suspected of having peripheral artery disease (PAD) with risk factors such as smoking, diabetes, hypertension, and hyperlipidemia?

Workup for Peripheral Artery Disease

For patients with risk factors including smoking, diabetes, hypertension, and hyperlipidemia, the workup begins with a targeted vascular history and physical examination, followed immediately by resting ankle-brachial index (ABI) testing as the required initial diagnostic test. 1, 2

Step 1: Identify At-Risk Patients Requiring Evaluation

You should evaluate patients who meet any of these criteria 1, 2:

• Age ≥65 years (regardless of other factors)
• Age 50-64 years with atherosclerotic risk factors (smoking, diabetes, hyperlipidemia, hypertension)
• Age <50 years with diabetes PLUS one additional atherosclerotic risk factor
• Known atherosclerotic disease in other vascular beds (coronary, carotid, renal arteries)

Step 2: Obtain Targeted Vascular History

Focus your history on these specific symptoms 1:

Exertional leg symptoms:

• Walking impairment described as fatigue, aching, numbness, or pain
• Document the exact location (buttock, thigh, calf, or foot)
• Record the relationship to exertion versus rest
• Note if symptoms resolve with rest (classic claudication pattern)

Critical limb ischemia indicators:

• Poorly healing or nonhealing wounds on legs or feet
• Pain at rest in the lower leg or foot
• Whether rest pain improves with leg dependency (hanging leg off bed)

Other vascular territories:

• Postprandial abdominal pain provoked by eating with weight loss (mesenteric ischemia)
• Family history of first-degree relative with abdominal aortic aneurysm

Critical pitfall: Approximately 40% of PAD patients have no leg symptoms, and two-thirds are asymptomatic—do not wait for symptoms to screen high-risk patients. 3, 4

Step 3: Perform Comprehensive Vascular Physical Examination

Blood pressure assessment 1, 2:

• Measure blood pressure in both arms at initial assessment
• Inter-arm difference >15-20 mmHg suggests subclavian or innominate artery stenosis

Pulse examination 1:

• Palpate and grade pulses at: brachial, radial, ulnar, femoral, popliteal, dorsalis pedis, and posterior tibial arteries
• Use standardized grading: 0 (absent), 1 (diminished), 2 (normal), 3 (bounding)

Auscultation 1:

• Listen for carotid bruits (note upstroke and amplitude)
• Auscultate abdomen and flanks for bruits
• Auscultate both femoral arteries for bruits

Lower extremity inspection 1:

• Remove shoes and socks completely
• Assess skin color, temperature, and integrity
• Examine intertriginous areas
• Document any ulcerations (location and characteristics)
• Look for signs of severe PAD: distal hair loss, trophic skin changes (thin, shiny, atrophic), hypertrophic nails

Abdominal examination 1:

• Palpate for aortic pulsation and estimate maximal diameter

Step 4: Obtain Resting Ankle-Brachial Index (ABI)

The resting ABI is the required initial diagnostic test for PAD 1, 2:

Measurement technique 1, 2:

• Patient supine position
• Use Doppler device to measure systolic blood pressures at brachial arteries (both arms)
• Measure systolic pressures at dorsalis pedis AND posterior tibial arteries (both ankles)
• Calculate ABI for each leg: divide the higher ankle pressure by the higher arm pressure

Diagnostic thresholds 1, 2:

• ABI ≤0.90: Confirms PAD diagnosis (68-84% sensitivity, 84-99% specificity)
• ABI 0.91-0.99: Borderline (consider exercise ABI if symptomatic)
• ABI 1.00-1.40: Normal
• ABI >1.40: Noncompressible vessels (arterial calcification, common in diabetes)

Critical pitfall: In diabetes, arterial calcification falsely elevates ABI >1.40, requiring alternative testing. 3

Step 5: Additional Testing Based on Initial ABI Results

If ABI >1.30 (noncompressible vessels) 1, 2:

• Obtain toe-brachial index or pulse volume recording
• This is particularly important in diabetic patients with calcified vessels

If ABI 0.91-1.30 (normal) but symptoms suggest PAD 1, 2:

• Perform exercise ABI testing
• Useful for patients without classic claudication but with exertional leg symptoms
• Measures ABI before and after standardized treadmill exercise

If ABI ≤0.90 (PAD confirmed) 1, 2:

• No additional vascular imaging needed initially unless planning revascularization
• Focus on comprehensive cardiovascular risk assessment and medical management

Step 6: Assess for Coexistent Vascular Disease

Critical consideration: PAD patients have markedly increased risk for myocardial infarction, stroke, and cardiovascular death due to coexistent coronary and cerebrovascular disease—cardiovascular ischemic events are MORE frequent than limb ischemic events. 1, 3

Evaluate for 1:

• Coronary artery disease (history, ECG, consider stress testing if planning revascularization)
• Cerebrovascular disease (carotid examination, history of TIA/stroke)
• Abdominal aortic aneurysm (especially if family history or atheroembolization features)
• Renal artery stenosis (if resistant hypertension or unexplained renal dysfunction)

Key Diagnostic Pitfalls to Avoid

Neuropathy in diabetics masks ischemic pain, increasing risk of foot ulceration and limb-threatening complications without warning symptoms. 3 These patients require regular foot inspection even without symptoms.

Normal pulse examination has limited sensitivity—the pulse exam must be supplemented by objective ABI testing in at-risk patients. 1

Do not obtain arterial imaging if postexercise ABI is normal, unless you suspect non-atherosclerotic causes like popliteal entrapment syndrome or adventitial cysts. 1

Consider non-atherosclerotic causes in younger patients (<50 years), especially 1, 3:

• Buerger disease (thromboangiitis obliterans) in young smokers
• Popliteal artery entrapment in young adults with exercise-induced symptoms
• Fibromuscular dysplasia
• Vasospastic disorders
• Thromboembolic disease from cardiac source