Microembolic signals and carotid plaque characteristics in patients with asymptomatic carotid stenosis.

OBJECTIVE To investigate the association between carotid plaque characteristics and the occurrence of cerebral microemboli signals (MES) and subsequent ischemic events in patients with asymptomatic carotid stenosis (ACS). DESIGN Sixty-two asymptomatic patients with 50-99% carotid stenosis underwent transcranial Doppler (TCD) monitoring to determine the relationship between MES and plaque characteristics. The patients were followed for 1 year, and the incidence of transient ischemic attack (TIA)/stroke was studied. RESULTS MES were found in 10/62 of the patients at baseline, and there was a significant difference between the patients with moderate stenosis and those with severe stenosis on the presence of MES (p = 0.016). Furthermore, MES were more frequently found in patients with irregular and/or heterogeneous plaques than in those with regular (p = 0.028) and/or homogeneous plaques (p = 0.021). The incidence of TIA/stroke occurred more frequently in patients with MES than those without MES (p = 0.009). The proportion of progressive carotid stenosis was 4/50 in the patients with 50-99% stenosis during 1 year follow-up. CONCLUSION Asymptomatic patients (with 50-99% carotid stenosis) with MES presented a significantly increased frequency of severe stenosis, with irregular and heterogeneous plaques.