Ankle-brachial index in diabetic patients - which upper cut-off value is to be used?

Abstract

Objectives: In diabetic patients, there is a discrepancy in guidelines for ankle-brachial index (ABI) screening for peripheral arterial disease (PAD). While diabetes organizations suggest the value of upper limit of normal ABI to be 1.3, cardiologists recommend 1.4. Also, guidelines recommend using the higher value of ankle pressure (HAP) but multiple recent studies propose the opposite (LAP).

Methods: In this prospective study, we performed ABI measurements in 62 diabetic patients. Results were calculated by comparing higher and lower values of ankle pressure to those of duplex ultrasound (stenosis ≥ 50 % was considered PAD). Special attention was paid to patients with high and non-measurable ABI.

Results: LAP ABI appears to be a preferable method for PAD screening in diabetics. The upper cut-off value of 1.4 yielded better results with sensitivity of 93 % and negative predictive value of 91 %. No limbs with ABI between 1.3 and 1.4 with significant stenosis were found. However, using HAP for the upper cut-off captured additional PAD patients. PAD was abundant among patients with high or non-measurable ABI.

Conclusions: LAP should be used for assessing low ABI (cut-off 0.9) while HAP for detecting the abnormally high ABI. The preferable high ABI cut-off is 1.4. Condition with abnormally high or non-measurable ABI should be considered as PAD (Tab. 3, Ref. 22).

Keywords: ankle-brachial index; diabetes; lower extremity arterial disease cut-off.; peripheral arterial disease.