CEREBRAL MICROEMBOLISM AND EARLY RECURRENT CEREBRAL OR RETINAL ISCHEMIC EVENTS

Background and Purpose We investigated whether cerebral microembolism as detected by transcranial Doppler ultrasonography (TCD) identifies p atients at an increased risk for early, recurrent cerebral or retinal ischemic events. Methods Records of consecutive patients examined duri ng a 40-month period in the Neurovascular Laboratory were reviewed for the presence of cerebral microembolism. Of the original 302 patients, 229 with 310 arteries met inclusionary criteria. Follow-up informatio n was obtained from the laboratory's database as well as the hospital records. Microembolus detection studies were performed on TC-2000 or T C-2020 instruments equipped with special software, and criteria establ ished a priori were used for microembolus selection. TCD testing was p erformed a median interval of 9 days after the initial symptoms of cer ebral ischemia. Severity of arterial stenosis was determined by cerebr al angiography or noninvasive methods. Results Microembolic signals we re detected more frequently in symptomatic (40/140: 28.6%) than asympt omatic (21/170; 12.4%) arteries (P<.001). Ten recurrent ischemic event s occurred during a median follow-up of 8 days after TCD examination, all in the territories of symptomatic arteries. Nine events occurred i n the territories of microembolic signal-positive arteries (9/61; 14.8 %) and one in the territory of a microembolic signal-negative artery ( 1/249; 0.4%) (P<.001). No association was detected in the subgroup wit h known cardiac lesions. Microembolic signals were more frequent in ar teries with lesions causing 70% or more stenosis or occlusion (26/99; 26.3%) than in those with a degree of stenosis less than 70% (17/126, 13.5%) (P=.016). Conclusions In this retrospective study, microembolic signals were more common in the territories of symptomatic arteries a nd particularly those with severely stenotic lesions. During a short f ollow-up, recurrent ischemic events were more common along the territo ries of arteries with TCD-detected microembolism and previous symptoms of cerebral or retinal ischemia.