Is the ankle-brachial index a useful screening test for subclinical atherosclerosis in asymptomatic, middle-aged adults?

Abstract

BACKGROUND: Measurement of the ankle-brachial index (ABI) is recommended as a screening test for cardiovascular risk prediction in individuals > or = 50 years old; however, there is little data regarding the utility of the ABI as a screening test in individuals for whom physicians actually order non-invasive testing for cardiovascular risk prediction. METHODS: This study included 493 consecutive asymptomatic patients without known atherosclerotic vascular disease who were referred by their physician for measurement of the ABI and ultrasound measurement of carotid intima-media thickness (CIMT). ABI values were classified as "reduced" (<0.9), "normal" (0.9-1.3), and "increased" (>1.3). RESULTS: The mean age of the patients was 55.3 (standard deviation 7.5) years. Only 1 patient had a reduced ABI (0.2%). ABI values tended to be higher in those with increased CIMT (P=0.051); however, CIMT was not significantly different between those with normal and increased ABI values (P=0.802). There were no significant differences in the prevalence of traditional cardiovascular risk factors or carotid plaque presence among the ABI groups. CONCLUSIONS: Despite recommendations, the ABI is not sensitive as a screening tool for detecting subclinical atherosclerosis in asymptomatic middle-aged individuals.