Ankle-Brachial Index: Diagnostic Tool of Peripheral Arterial Disease and Predictor of Cardiovascular Risk—An Update of Current Knowledge

The ankle-brachial index (ABI) was introduced as a screening method for the diagnosis of lower extremity peripheral arterial disease (PAD). Later findings recognized ABI as a prognostic marker of adverse cardiovascular events due to its relation to atherosclerosis in other vascular territories. This narrative review aims to appraise the validity, reliability, and utility of ABI in the detection of PAD and the determination of global atherosclerotic cardiovascular risk. While the ABI value can be influenced by different physiological characteristics including age, sex, body position, and techniques used for ABI determination, it has high specificity and reproducibility in the assessment of vascular patients. In conclusion, when used correctly, the ABI remains a reliable and invaluable indicator of lower-limb perfusion and a useful tool for predicting the risk of future cardiovascular events. However, its underutilization in clinical settings is noteworthy.