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

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.