Which non-invasive diagnostic test is commonly used to diagnose peripheral vascular disease?

• A. Ankle-Brachial Index (ABI)
• B. CT angiography
• C. Coronary angiography
• D. Venous Doppler

Answer: (A)

Ankle-Brachial Index testing is the simplest non-invasive way to diagnose peripheral arterial disease. It directly measures arterial perfusion in the legs by comparing the systolic blood pressures in the ankles with those in the arms. A normal ABI is about 1.0 to 1.4; an ABI at or below 0.90 indicates PAD, helping confirm the diagnosis and gauge severity.

This test is quick, inexpensive, and widely available at the bedside, requiring only a Doppler probe and blood pressure cuffs. Its practicality and reliability make it the go-to initial screening tool for suspected PAD. It also provides a baseline to monitor progression or response to therapy over time.

Be aware of limitations: in people with heavily calcified arteries (common in diabetes or chronic kidney disease), the arteries may be noncompressible, leading to falsely high readings, in which case the toe-brachial index or other imaging may be more informative.

The other options aren’t used as routine first-line tests for diagnosing PAD. CT angiography can visualize vessels but involves contrast and radiation and is usually reserved for detailed anatomical assessment or planning interventions. Coronary angiography targets the heart’s arteries, not the limbs. Venous Doppler assesses the venous system and is used for conditions like DVT, not arterial PAD.