ASYMPTOMATIC INTERNAL CAROTID-ARTERY STENOSIS DEFINED BY ULTRASOUND AND THE RISK OF SUBSEQUENT STROKE IN THE ELDERLY - THE CARDIOVASCULAR HEALTH STUDY

Background and Purpose-We sought in this study to relate carotid ultra sound findings in asymptomatic older adults to the 5-year risk of vari ous cerebrovascular outcomes used in the Asymptomatic Carotid Atherosc lerosis Study (ACAS). Methods-The Cardiovascular Health Study (CHS) is a longitudinal study of people 65 years and older. Analyses of intern al carotid artery stenosis defined by multiple different cutoffs of pe ak systolic velocity, rather than one particular cutoff, were performe d in the 5441 participants who underwent carotid ultrasound and lacked a history of transient ischemic attack or stroke. The 5-year risks of 7 cerebrovascular disease outcomes used in ACAS were estimated for ea ch cutoff. Results-Associations with the 5-year risk of outcomes were substantially elevated only at cutoffs with high peak systolic velocit ies. In this population, the number of people with such high velocitie s was small. For example, with a cutoff of approximately 2.5 m/s, sugg esting a stenosis of >70%, the 5-year risk of an ipsilateral fatal or nonfatal stroke was 5%, and only 0.5% of the group had velocities at l east this high. Conclusions-In a group of older adults likely to parti cipate in a screening program, as evidenced by willingness to particip ate in CHS, high peak systolic velocities consistent with high-grade c arotid stenosis were uncommon and risk of subsequent cerebrovascular d isease outcomes was relatively low. These findings do not suggest that similar populations of older adults would benefit from a program usin g ultrasound to screen for asymptomatic carotid stenosis.