Asymptomatic carotid bruit and risk of stroke. The Framingham study.

Carotid bruit was routinely sought in the Framingham cohort and during eight years appeared in 66 men and 105 women, all of whom were asymptomatic. The incidence increased with age equally in the two sexes from 3.5% at 44 to 54 years, to 7.0% at 65 to 79 years. The eight-year incidence was greater in diabetes and hypertensive subjects. Transient ischemic attacks appeared in eight (two alone) and stroke in 21 of the 171, a stroke rate more than twice expected for age and sex. More often than not, cerebral infarction occurred in a vascular territory different from that of the carotid bruit, often in the posterior circulation, and ruptured aneurysm, embolism from the heart, and lacunar infarction was the mechanism of stroke in nearly half the cases. Incidence of myocardial infarction was also increased twofold in those with asymptomatic carotid bruit. General mortality were also increased; 1.7-fold with men, and 1.9-fold in women, with 79% of the deaths owing to cardiovascular disease, including stroke. Carotid bruit is clearly an indicator of increased stroke risk but chiefly as a general and nonfocal sign of advanced atherosclerotic disease and not necessarily as an indicator of local arterial stenosis preceding cerebral infarction.