Borderline peripheral arterial disease.

Peripheral arterial disease (PAD), along with coronary artery disease and cerebrovascular disease, is a manifestation of systemic atherosclerosis. These cardiovascular diseases (CVDs) are the leading cause of death in the world, representing 30% of all global deaths. Although population-based studies indicate that PAD has a relatively benign course in the legs, patients with PAD show more cardiovascular comorbidity and have at least twofold risk of fatal coronary artery disease and cerebrovascular accidents compared with the general population. These studies suggest that noninvasive testing using the ankle-brachial index (ABI) is also an accurate marker of subclinical CVD and thus may hold promise for early identification of individuals at the greatest risk for major CVD events.The Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II) defines a cutoff ABI value of 0.90 or less for diagnosing PAD at rest. This threshold value has been reported to be 95% sensitive in detecting angiogram-positive PAD and almost 100% specific in identifying apparently healthy individuals. In persons without PAD, arterial pressures increase with greater distance from the heart, resulting in higher systolic blood pressures at the ankle than at the the brachial arteries. Thus, persons without atherosclerosis typically have an ABI greater than 1.00. But what is the significance of ABI values between 0.91 to 1.00, which are conventionally regarded as 'no disease'? The present article gives an overview of current knowledge of borderline PAD (ie, an ABI of 0.91 to 1.00).