The importance of intraoperative detection of residual flow abnormalities after carotid artery endarterectomy

Abstract

The efficacy of carotid endarterectomy in the prevention of strokes mandates low perioperative morbidity, as well as a low incidence of late ipsilateral stroke. This prospective study involving 430 patients (461 carotid endarterectomies) correlated the results of intraoperative assessment with end points of stroke and residual/recurrent internal carotid artery (ICA) stenosis. Adequacy of the repair was assessed by ultrasound studies (duplex scan and pulsed Doppler spectral analysis) alone (n = 142), ultrasound studies and arteriography (n = 268), or clinical inspection (n = 51). After operation, duplex ultrasonography was used to confirm patency and categorize severity of ICA stenosis. At operation 26 carotid endarterectomy sites (5.6%), were revised based on intraoperative studies. Perioperative (30-day) morbidity rates were similar in patients with normal, mildly abnormal, or no ultrasound completion studies. There were six permanent (1.3%) and 12 temporary (2.6%) neurologic deficits and six deaths, including four fatal strokes and two fatal myocardial infarctions. By life-table analysis, the incidence of greater than 50% diameter-reducing ICA stenosis or occlusion was increased (p < 0.007, log-rank test) in patients with residual flow abnormality or no study. More important, patients with normal intraoperative flow studies had a significantly lower rate of late ipsilateral stroke compared with the remaining patient cohort (p = 0.04, log-rank test). During the mean 30-month follow-up interval, the incidence of late stroke was increased (p = 0.00016) in patients with ICA restenosis or occlusion (3/35) compared with patients without recurrent stenosis (3/426). Confirmation of a normal repair at operation affords the best opportunity to minimize ischemic neurologic events and anatomic restenosis after carotid endarterectomy.