Guideline Compliant Minimum Asymptomatic Carotid Endarterectomy Surgeon and Hospital Volume Cutoffs

Abstract

There is a known association between volume and outcomes after carotid endarterectomy (CEA). A recent analysis suggested rates of stroke and death do not significantly reduce after a surgeon volume cutoff of 20 CEAs per year. However, these results would severely limit access. The objective here is to identify a lower optimal cutpoint for surgeon and hospital volume for asymptomatic CEA. We evaluated asymptomatic CEA patients using The New York Statewide Planning and Research Cooperative System database from 2000-2014. The relationship of 3-year averaged volumes for surgeons and hospitals to 30-day stroke were assessed using multiple logistic regression and included both hospital and surgeon volume in all analyses. Optimized cutpoints were the lowest significant volume cutoff that minimized the adjusted odds ratio of stroke. We studied 32,549 CEAs performed by 271 surgeons in 136 centers by vascular surgeons. The median surgeon volume was 26.3(IQR:12.3-51.7) and the median hospital volume was 67(IQR:36.3-119.3). The surgeon volume cutpoint was 3 and the hospital volume cutpoint was 6 cases per year. There were 756(2.3%) procedures performed by surgeons with a volume <3 and 560 (1.7%) procedures performed by hospitals with a volume <6. Perioperative stroke and death rates were 2.0% (95%CI:1.8-2.1) and 3.8% (95%CI:2.6-5.5) for an average yearly surgeon volume ≥3 and <3 (p=0.070), respectively. The combined Stroke and death rate was 2.0% (95%CI:1.8-2.1) and 4.8% (95%CI:3.2-7.0) for an average yearly center volume ≥6 and <6 (p=0.007), respectively. A combined surgeon and hospital volume variable also predicted outcomes and low volume procedures did not meet previously proposed AHA and SVS quality measures. These data demonstrate an improvement in outcomes at a lower volume threshold than previously reported. These modest cutoff values should be used for asymptomatic CEA volume guideline formation and for future studies, after accounting for the impact of other important factors that may be driving volume-outcomes relationships in asymptomatic CEA.