Incidence of shunting during carotid endarterectomy: regional versus general anesthesia

Introduction. Carotid endarterectomy (CEA) is the most common non-cardiac vascular surgical procedure performed in the U.S. Recently several multicenter randomized trials evaluated the efficacy of CEA in preventing strokes in symptomatic and asymptomatic patients with different degrees of stenosis. The favorable results of these studies indicate that the number of CEA procedures will likely increase in the near future.1'2 Shunts are used frequently during CEA and they are associated with potentially serious complications, e.g. microembolization and vessel trauma. The two most commonly used anesthetic techniques during CEA, are general anesthesia and cervical plexus block (CPB) anesthesia. With CPB anesthesia, the awake patient allows trial cross-clamping to determine the potential for neurological deficits. Such a trial permits the selected use of shunting. Methods. We studied the incidence of shunting in 100 ASA III patients (52 males and 48 females, 50 to 90 years of age) undergoing CEA in our institution. In 50 of these patients general anesthesia was used and in 50 CPB anesthesia was used. In the general anesthesia group, 45 patients (90%) were shunted. In 3 out of the 5 non-shunted patients, a shunt was not placed due to technical difficulties. In the CPB anesthesia group, only 9 patients (17%) were shunted. However, only 2 of these 9 patients required shunting because of neurological symptoms during trial cross-clamping. In the remaining 7, the surgeon felt uncomfortable not using the shunt due to poor carotid artery back flow in spite of the patients showing no neurological deficits during the trial cross-clamping. All one hundred patients had an uneventful postoperative cardiac and neurological recovery. Results. In our study, the incidence of shunting was significantly less in the CPB anesthesia group than in the general anesthesia group (17% versus 90%). Avoiding shunt placement not only eliminates the risk of microembolization and vessel trauma but also makes surgical conditions less difficult. In addition, the time associated with the insertion and removal of the shunt is eliminated thereby reducing cost and improving efficiency of the procedure.