Possible determinants of early microembolism after carotid endarterectomy

Background and Purpose-High numbers of microembolic signals (MES) have been associated with increased risk of postoperative stroke after carotid endarterectomy (CEA). We sought to identify factors predictive of postoperative MES. Methods-Transcranial Doppler monitoring of the ipsilateral middle cerebral artery for MES was performed for 30 minutes during the first postoperative hour in sequential patients undergoing CEA. Stepwise binomial logistic regression analysis was performed to identify preoperative and intraoperative variables that predicted the occurrence of postoperative MES. Results-We studied 141 patients (mean age, 69 years); 102 (72%) were male, and 69 (49%) had at least 1 MES (range, 1 to 118) detected in the first postoperative hour. The risk of postoperative MES was greater in women (P=0.027), patients not receiving antiplatelet therapy (P=0.033), and patients undergoing left-sided CEA (P=0.049). Other variables such as residual stenosis seen on completion angiography and operative technique were not associated with postoperative MES. Conclusions-Postoperative MES were most likely in women, patients not receiving preoperative antiplatelet therapy, and patients who had a left CEA. Microembolism might explain why these same factors are associated with higher rates of perioperative stroke.