The Limitations of Ankle Brachial Index when used Alone for the Detection/Screening of Peripheral Arterial Disease in a Population with an Increased Prevalence of Diabetes

Abstract

A retrospective analysis was performed comparing the effectiveness of ankle brachial index (ABI) to Doppler waveform analysis for the detection of peripheral arterial disease (PAD) in a group of patients with an estimated 31% prevalence of diabetes. A total of 21,199 ankle pressures and corresponding Doppler waveforms were correlated; 8,628, or 41%, of the ankle pressures were within normal limits; 8,335, or 40%, of the ankle pressures were below normal limits; and 4,042, or 19%, of the ankle pressures were noncompressible. Using ABI alone for screening in a population with a high incidence of diabetes is significantly limited because of noncompressible ankle pressures caused by arterial calcification. A total of 19% of the segments evaluated in this population yielded noncompressible vessels. The prevalence of PAD, detected by Doppler waveform analysis in the segments with non-compressible ankle pressures, was 69%. Additional modalities such as Doppler waveform analysis would further increase the accuracy of screening for PAD in this population. Alternately, using the ABI alone for the detection of PAD can be improved by interpreting ABIs greater than 1.2 as positive results because of the high prevalence of PAD in this group.