Carotid endarterectomy after NASCET and ACAS: A statewide study

Purpose: Since the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and the Asymptomatic Carotid Artery Stenosis Study (ACAS) established the efficacy of carotid endarterectomy at large academic centers, there have been two community-based studies of outcomes after this operation. The purpose of this study was to perform a statewide survey to evaluate postoperative morbidity and mortality after carotid endarterectomy among patients throughout Maine. Methods: A statewide registry was established to collect prospective data on carotid operations from January I to December 31, 1995. All surgeons and hospitals in the state were solicited to participate. All carotid endarterectomies were intended to be included; the only exclusion criterion was out-of-state residence. Comorbidities, preoperative studies, surgical indications, operative technique, and postoperative outcomes were analyzed. State administrative data were used to assess registry coverage. Results: Ten of 17 hospitals participated, and 58% of all carotid endarterectomies performed in the state were included. Three hundred sixty-four operations were entered into the registry, forty-four percent of the operations were performed for transient ischemic attack, 37% for asymptomatic stenosis, and 19% for stroke. The postoperative stroke rate was 2.5% with a total neurologic complication rate of 4.7% (transient ischemic attack and stroke). There was one postoperative death (mortality rate 0.3%). Patients with symptoms had a higher incidence of postoperative stroke (4.0% vs 0% asymptomatic; p < 0.05) and transient ischemic attacks (3.8% vs 0.8% asymptomatic). Hospital stroke rates varied from 0% to 7%. Stroke rate did not differ significantly between low-volume hospitals (2 to 28 patients/year, 3.3%) and high-volume hospitals (29 to 101 patients/year, 2.3%) or between low-volume surgeons (fewer than 11 operations/year, 1.7%) and high-volume surgeons (more than 12 operations/year, 2.4%). Among 26 reporting surgeons, stroke rate varied from 0% to 10%; the absolute number of strokes per surgeon varied between zero and two. Conclusion: The statewide registry showed a postoperative stroke plus death rate of 2.8%, comparable with the NASCET and ACAS findings. Although this study had inherent limitations, the results from one state, including a variety of community practices, achieved results comparable with those of landmark trials.