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Cerebral microembolism and early recurrent cerebral or retinal ischemic events
V L Babikian1, C A Wijman, C Hyde
1Department of Neurology, Boston University School of Medicine, MA 02130, USA.
Insights
Transcranial Doppler ultrasonography (TCD) detected microemboli in symptomatic arteries, indicating a higher risk for recurrent ischemic events. This finding highlights TCD
Area of Science:
- Neuroscience
- Vascular Medicine
- Diagnostic Imaging
Background:
- Cerebral microembolism is a potential indicator of ischemic events.
- Transcranial Doppler ultrasonography (TCD) is a noninvasive tool for detecting microemboli.
Purpose of the Study:
- To determine if TCD-detected cerebral microembolism predicts early, recurrent ischemic events in patients.
- To assess the association between microemboli and arterial stenosis severity.
Main Methods:
- Retrospective review of 229 patients with 310 arteries over 40 months.
- Microembolus detection using TC-2000 or TC-2020 instruments.
- TCD performed a median of 9 days post-symptoms; stenosis assessed via angiography or noninvasive methods.
Main Results:
- Microembolic signals were more frequent in symptomatic (28.6%) versus asymptomatic (12.4%) arteries (P < .001).
- Ten recurrent ischemic events occurred within 8 days post-TCD, primarily in territories with microemboli (14.8% vs 0.4%; P < .00).
- Microemboli were more common in arteries with ≥70% stenosis (26.3%) than <70% (13.5%; P = .016).
Conclusions:
- TCD-detected microemboli are more prevalent in symptomatic arteries, especially those with severe stenosis.
- Recurrent ischemic events are more frequent in patients with TCD-identified microemboli and prior ischemic symptoms.
Background And Purpose:
We investigated whether cerebral microembolism as detected by transcranial Doppler ultrasonography (TCD) identifies patients at an increased risk for early, recurrent cerebral or retinal ischemic events.
Methods:
Records of consecutive patients examined during 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 information was obtained from the laboratory's database as well as the hospital records. Microembolus detection studies were performed on TC-2000 or TC-2020 instruments equipped with special software, and criteria established a priori were used for microembolus selection. TCD testing was performed a median interval of 9 days after the initial symptoms of cerebral ischemia. Severity of arterial stenosis was determined by cerebral angiography or noninvasive methods.
Results:
Microembolic signals were detected more frequently in symptomatic (40/140; 28.6%) than asymptomatic (21/170; 12.4%) arteries (P < .001). Ten recurrent ischemic events occurred during a median follow-up of 8 days after TCD examination, all in the territories of symptomatic arteries. Nine events occurred in 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 < .00). No association was detected in the subgroup with known cardiac lesions. Microembolic signals were more frequent in arteries 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 and particularly those with severely stenotic lesions. During a short follow-up, recurrent ischemic events were more common along the territories of arteries with TCD-detected microembolism and previous symptoms of cerebral or retinal ischemia.