Microembolic signals in symptomatic and asymptomatic internal carotid artery occlusive disease

Cerebral microembolic signals (MES) in patients with carotid occlusive disease can be detected by transcranial Doppler (TCD) examination. The aim of this study was to determine the incidence and prevalence of MES in both symptomatic and asymptomatic patients with stenosis or occlusion of the internal carotid artery (ICA).

This study included 40 patients (mean age 64.3 +/-11.4) with ICA stenosis or occlusion, diagnosed with colour Doppler duplex. TCD monitoring of the middle cerebral artery downstream to ICA pathology was performed for 45 minutes. Acute carotid territory symptoms were present in 26 (65%) patients. Each patient within this group had neuroimaging performed. Antiplatelet drugs were administered in 35 patients (87.5%).

MES were detected in 11 patients (27.5%). Median number of MES in all studied patients was 0. MES were present only in patients with ICA stenosis ł 40% and in the symptomatic group. Two patients (18.2%) with ICA occlusion showed MES. There was relationship between risk of MES and age (OR = 2.7/10 years, 95% CI 1.1-6.7, p = 0.02), sex (more frequent in male: OR = 16.9, 95% CI 1.1-259; p = 0.04) and ischaemic lesions in computed tomography (OR = 9.8, 95% CI 1.0-99.1, p = 0.04). Antiplatelet treatment did not influence the occurrence of MES in the study group (OR = 1.6; 95% CI 0.1-17.4; p = 0.69).

MES were detected in above 1/4 of patients and an associated with the degree of ICA stenosis and the presence of ischaemic lesions found in CT. This may suggest a correlation between MES an stroke. Plaque morphology does not influence the prevalence of MES.