How to Interpret the Ankle-brachial Index for Diagnosis of Peripheral Arterial Disease in Clinical Practice

The ankle-brachial index (ABI) plays a key role in diagnosis of peripheral arterial disease (PAD) in clinical practice. Moreover, pulse wave velocity (PWV), upstroke time (UT), percent mean arterial pressure (%MAP), and toe-brachial index (TBI) are useful indices of predicting the presence of PAD even if ABI at rest is still within the normal range, thus improving patients risk stratification and helping in clinical decisions, especially in circumstances of discrepancy between symptoms and ABI at rest. The aim of this review is to investigate how to interpret the results of these indices for understanding of etiology, diagnosis, and severity in evaluation of PAD. Case 1: a discrepancy between PWV and pulse waveform in a patient with bilateral common femoral artery stenosis; Case 2: a discrepancy between ABI and TBI in a patient with bilateral diffuse stenosis of infra-popliteal artery; Case 3: a discrepancy within the normal range ABI between left and right in a patient with left superficial femoral artery occlusion; Case 4 and 5: a discrepancy between ABI and clinical symptoms in a patient with scleroderma and Buerger’s disease.