The impact of intraoperative shunting on early neurologic outcomes after carotid endarterectomy

Background Although the need for intraoperative shunting during carotid endarterectomy (CEA) is intensely debated, relatively few studies have compared the neurologic outcomes of patients undergoing CEA with or without shunts. The objective of our analysis was to determine the impact of intraoperative shunting during CEA on the incidence of postoperative stroke. Methods The 2012 CEA-targeted American College of Surgeons National Surgical Quality Improvement Program database was used for this analysis. The preoperative and operative characteristics of patients undergoing CEA with or without intraoperative shunting were compared. From this overall sample, propensity score techniques were then used to match patients with or without intraoperative shunting for a number of variables, including age, degree of ipsilateral and contralateral carotid stenosis, presence of several anatomic or physiologic risk factors, anesthesia modality, and use of patch angioplasty vs primary arteriotomy closure. The 30-day postoperative mortality and combined stroke/transient ischemic attack (TIA) rates of this matched cohort were then compared. A similar analysis was also performed on a subgroup of patients with severe stenosis or occlusion of the contralateral carotid artery. Results A total of 3153 patients were included for initial analysis (2023 "no-shunt" patients vs 1130 "shunt" patients). From this overall sample, propensity score matching yielded a cohort of 1072 patients with or without intraoperative shunt placement who were well matched for all known patient- and procedure-related factors. There was no significant difference in the incidence of postoperative stroke/TIA between the two groups of this matched cohort (3.4% in the no-shunt group vs 3.7% in the shunt group; P =.64). Analysis of a similarly well matched subgroup of patients with severe stenosis or occlusion of the contralateral carotid artery demonstrated a statistically nonsignificant increase in the incidence of postoperative stroke/TIA with the use of intraoperative shunting (4.9% in the no-shunt group vs 9.8% in the shunt group; P =.08). Conclusions There is no clinical benefit to intraoperative shunting during CEA, even in patients who may be at high risk for intraoperative cerebral hypoperfusion due to severe stenosis or occlusion of the contralateral carotid artery.