The ankle-brachial pressure index (ABPI) in a diabetic patient is falsely elevated. Which alternative non-invasive test provides more accurate assessment of peripheral perfusion in such patients?

• A Exercise treadmill testing with post-exercise ABPI
• B Toe brachial pressure index (TBPI) using photoplethysmography ✓
• C Duplex ultrasound of femoral vessels
• D CTA of the lower limb vessels

Explanation

In diabetics, medial arterial calcification causes non-compressible vessels, falsely elevating ABPI (often >1.3). Toe arteries (digital arteries) are spared from calcification, making the toe brachial index (TBI) measured by photoplethysmography more accurate — a TBI <0.7 indicates PAD and <0.3 indicates critical limb ischaemia. Exercise ABPI is useful for claudication but does not overcome the calcification problem. Duplex and CTA provide anatomical mapping but not a functional index.

Reference: Bailey & Love's Short Practice of Surgery, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.