What test is used to diagnose Peripheral Vascular Disease (PVD)?

Diagnostic Testing for Peripheral Vascular Disease (PVD)

The ankle-brachial index (ABI) is the recommended first-line diagnostic test to establish the diagnosis of PVD in patients with suspected disease. 1

Initial Diagnostic Approach

Resting Ankle-Brachial Index (ABI)

• The resting ABI with or without segmental pressures and pulse volume recordings is the cornerstone initial test for diagnosing PVD in patients with history or physical examination findings suggestive of disease 1
• The test is performed by measuring systolic blood pressures at both brachial arteries and at the ankles (dorsalis pedis and posterior tibial arteries) in the supine position using a Doppler device 1
• The ABI for each leg is calculated by dividing the higher ankle pressure (dorsalis pedis or posterior tibial) by the higher arm pressure 1
• The test has 68-84% sensitivity and 84-99% specificity for detecting significant stenosis 1, 2

ABI Interpretation and Reporting

Results should be categorized as follows 1:

• Abnormal: ABI ≤0.90 (confirms PVD diagnosis)
• Borderline: ABI 0.91-0.99 (possible PVD, requires further testing)
• Normal: ABI 1.00-1.40
• Noncompressible: ABI >1.40 (indicates calcified vessels, requires alternative testing)

When Resting ABI is Insufficient

For Noncompressible Arteries (ABI >1.40)

• Toe-brachial index (TBI) with waveforms should be performed when the resting ABI is >1.40, which commonly occurs in patients with diabetes or advanced chronic kidney disease 1
• A TBI ≤0.70 is considered abnormal and diagnostic of PVD 1
• This is particularly important as medial arterial calcification can falsely elevate ABI readings 1

For Normal or Borderline ABI with Symptoms

• Exercise treadmill ABI testing is recommended for patients with exertional leg symptoms and normal (>0.90) or borderline (0.91-0.99) resting ABI 1
• The test objectively measures functional limitations and can unmask moderate stenosis not apparent at rest 1
• A post-exercise ankle pressure decrease >30 mmHg or ABI decrease >20% is diagnostic for PVD 1
• Studies show that 31% of symptomatic patients with normal resting ABI have abnormal post-exercise ABI 3

Additional Physiological Testing

Segmental Pressures and Waveforms

• Segmental lower extremity blood pressures with pulse volume recordings (PVR) and/or Doppler waveforms can be performed in addition to resting ABI to localize anatomic disease segments (aortoiliac, femoropopliteal, infrapopliteal) 1
• This is particularly useful when planning revascularization procedures 1

For Chronic Limb-Threatening Ischemia (CLTI)

When CLTI is suspected, additional perfusion assessment is reasonable 1:

• Toe pressure/TBI with waveforms
• Transcutaneous oxygen pressure (TcPO₂)
• Skin perfusion pressure (SPP)

These tests help assess arterial perfusion severity and predict wound healing potential 1

Anatomic Imaging (Reserved for Revascularization Planning)

Anatomic imaging studies are generally not required for initial diagnosis but are reserved for symptomatic patients being considered for revascularization 1:

• Duplex ultrasound (85-90% sensitivity, >95% specificity for >50% stenosis) 1
• Computed tomography angiography (CTA) (96-98% sensitivity and specificity for aortoiliac disease) 1
• Magnetic resonance angiography (MRA) (95% sensitivity for segmental stenosis) 1
• Invasive catheter angiography (typically only when intervention is planned) 1, 4

Common Pitfalls and Caveats

• Nearly half of symptomatic patients referred for PVD evaluation have normal resting ABI, making exercise testing critical in this population 3
• ABI sensitivity is particularly low in elderly patients and those with diabetes due to arterial calcification 2
• Physical examination findings alone are insufficient and must be confirmed with objective testing 5
• Only one-third of PVD patients present with typical claudication symptoms, so maintain high clinical suspicion even with atypical presentations 5
• Bilateral arm blood pressure measurement is required at initial assessment to identify the higher pressure for accurate ABI calculation and to detect subclavian stenosis 1