Fowkes FGR et al. (2006) Ankle-brachial index and extent of atherothrombosis in 8891 patients with or at risk of vascular disease: results of the international AGATHA study. Eur Heart J 27: 1861–1867

Atherothrombosis causes major cardiovascular and cerebrovascular mortality and morbidity, but early identification of individuals at risk is problematic. Ankle–brachial index (ABI) has been proposed as a simple, inexpensive test for identifying the presence of disease in the peripheral arterial bed, which indicates an increased risk of major cardiovascular events. The prospective, multicenter AGATHA study aimed to determine whether a low ABI was related to the number and site of affected vascular beds in patients with vascular disease, and to the number of risk factors present in at-risk patients without known vascular disease.

Of 8,891 patients aged ≥55 years recruited consecutively within 24 countries, 7,099 were defined as having vascular disease and 1,792 as being at risk of vascular disease (≥2 risk factors). Nearly a third of at-risk patients had an abnormal ABI (≤0.9), indicating undiagnosed peripheral arterial disease. Lower ABI was marginally associated with an increased number of risk factors (P = 0.02), but not with the types of risk factor present. As many as 40.5% of patients with peripheral arterial disease—of whom 65.2% had one affected arterial bed, 27.6% two, and 7.1% all three—had an abnormal ABI; low ABI was associated with the site and number of affected arterial beds (P <0.001).

The authors conclude that ABI could be used to provide more-precise estimates of future risk of major cardiovascular events and death in both patients with vascular disease and those at increased risk, guiding treatment and disease prevention. Longer-term studies are in progress.