Microembolic signals and carotid plaque morphology: a study of 71 patients with moderate or high grade carotid stenosis

Objectives - To determine whether particular carotid plaque features on ultrasound are more likely to produce microembolic signals (MES). Patients and methods - We have reviewed 71 patients with moderate or high grade carotid stenosis established by ultrasound (30-99%). Plaque appearance was classified according to five subtypes. Transcranial monitoring of the middle cerebral arteries was performed on each patient. Results - MES were more frequently encountered in patients with anechogenic/hypoechogenic plaques compared with isoechogenic/hyperechogenic lesions (P < 0.01). MES+ patients presented also more frequently an irregular surface of the plaque and more severe stenosis, however, the differences did not reach significance. There was no relationship between the presence of MES and a history of stroke or transient ischaemic attack (TIA). When considering the different above mentioned variables (logistic regression), only plaque morphology appeared to be a risk factor for the presence of MES. Conclusion - MES+ patients presented a significantly increased frequency of anechogenic/hypoechogenic plaques. As MES may be a marker of increased risk of stroke, the clinical significance of this particular association should be further investigated.