Role of transcranial Doppler and stump pressure during carotid endarterectomy

Abstract

Background and Purpose: The aim of our study was to clarify the pathophysiology of perioperative cerebral complications during carotid endarterectomy in our series. Methods: By means of transcranial Doppler ultrasonography and stump pressure measurement, we monitored 112 patients who underwent carotid endarterectomy under general anesthesia for symptomatic or asymptomatic severe carotid stenosis. Results: Of 18 patients who underwent carotid endarterectomy with intra-arterial shunt, 2 (11.1%) developed an ischemic stroke. Of the other 94 patients, one suffered a nucleocapsular hemorrhage and 5 had cerebral ischemic complications. In these 5 patients, the duration of clamping was significantly longer (mean±SD, 16.4±1.1 versus 12.7±2.6 minutes; P=.0019), and the decrease of middle cerebral artery mean velocity on clamping was significantly greater (mean±SD, 56.4±4.9% versus 28.8±20.2%; P=.0031), while stump pressure was not significantly different. Microembolic signals were recorded in 70 patients (62.5%) and were not associated with cerebral ischemic complications. The 7 patients who developed cerebral ischemic complications had a significantly higher percentage of stenosis in the contralateral internal carotid artery (mean±SD, 82.0± 17.8% versus 29.3±36.4%; P=.0018). Conclusions: The results of our study suggest that the major complications of carotid endarterectomy may be due to hemodynamic factors. Stump pressure alone is not a reliable indicator of hemodynamic changes that predict cerebral ischemia. Particulate microembolism may cause more subtle changes in cerebral parenchyma, but further studies are needed to clarify this point.