The Role of Ankle-Brachial Index for Predicting Peripheral Arterial Disease
The presence of peripheral arterial disease (PAD) is associated with higher cardiovascular morbidity and mortality, regardless of gender or its clinical form of presentation (symptomatic or asymptomatic). PAD is considered an independent predictor for cardiovascular mortality, more important for survival than clinical history of coronary artery disease.
The ankle brachial index (ABI) is a sensitive and cost-effective screening tool for PAD. ABI is valuable for screening of peripheral artery disease in patients at risk and for diagnosing the disease in patients who present with lower-extremity symptoms.
Compared to other diagnostic methods, ABI is superior because it is s a simple, noninvasive test, which could be routinely determined in all patients.
Normal cut-off values for ABI are between 0.9 and 1.4. An abnormal ankle-brachial index- below 0.9- is a powerful independent marker of cardiovascular risk.
There is an inverse correlation between ABI values, non-fatal cardiac events (myocardial infarction, stroke and heart failure exacerbation) and mortality (cardiovascular and global), the relation being nonlinear, patients with very low ABI (<0.3) having a significantly higher additional risk. Also, ABI values over 1.3-1.4 correlate with major adverse cardiovascular events.
Therefore, ABI can be considered a generalized atherosclerotic predictor, identifying patients at high risk for developing cardio- or cerebrovascular events and should be incorporated into routine clinical practice.