Ultrasonic echolucent carotid plaques predict future strokes

Background-We tested prospectively the hypothesis that stroke development c all be predicted by ec echolucency of carotid atherosclerotic plaques in pr eviously symptomatic and asymptomatic patients. Methods and Results-We followed incidence of ipsilateral ischemic strokes f or 4.4 pears in 111 asymptomatic and 135 symptomatic patients with greater than or equal to 50% relevant carotid artery stenosis. At inclusion. echoge nicity of carotid plaques and degree of stenosis were evaluated with high-r esolution B-mode ultrasound with computer-assisted image processing and Dop pler ultrasound, respectively. We observed 44 ipsilateral ischemic strokes. In symptomatic patients, relative risk of ipsilateral ischemic stroke for echolucent versus echorich plaques was 3.1 (95% CI. 1.3 to 7.3), whereas fo r 80% to 99% versus 50% to 79% stenosis, the relative risk was 1.4 (95% CI. 0.7 to 3.0). Relative to symptomatic patients with echorich 50% to 79% ste notic plaques, those with echorich 80% to 99% stenotic plaques, echolucent 50% to 79% stenotic plaques, and echolucent 80% to 99% stenotic plaques had relative risks of ipsilaterul ischemic strokes of 3.1 (95% CI, 0.7 to 14), 4.2 (95% CI, 1.2 to 15), and 7.9 (95% CI, 2.1 to 30), equivalent to absolu te risk increases of 11%, 18%, and 28%, This was not observed in previously asymptomatic patients. Conclusions-Echolucent plaques causing greater than or equal to 50% diamete r stcnosis by Doppler ultrasound are associated with risk of future stroke in symptomatic but not asymptomatic individuals. This suggests that measure ment of echolucency, together with degree of stenosis, may improve selectio n of patients for carotid endarterectomy.