Peripheral artery disease (PAD) screening in the asymptomatic population: why, how, and who?

Measurement of ankle-brachial index (ABI) was developed to assess peripheral artery disease (PAD) in patients with symptoms of peripheral ischemia being present at rest or only functionally dependent (intermittent claudication). Reduced ABI is caused by arterial obstruction between the aortic arch and feet (lower limb), which in the Western world is caused by atherosclerosis if not previous trauma. Whereas severity of intermittent claudication is only poorly related to ABI, cardiovascular outcomes are as follows: the lower the ABI the higher the incidence of cardiovascular events and death. Measuring ABI identifies asymptomatic persons at increased risk of cardiovascular morbidity and mortality: an ABI <0.9 doubles the risk of death of any cause. Reduced ABI is highly prevalent in the elderly population; 3% to 5% among people 60 years of age and >25% in people between 80 and 90 years of age. The majority of persons with reduced ABI are asymptomatic and therefore unaware of the increased risk they are living with, thus, screening by measuring ABI offers the opportunity for identifying persons at high risk. Unfortunately, most primary care physicians are not performing ABI in their office. Reimbursement issues along with inadequate knowledge of ABI are barriers for adoption and must be addressed.