Surgeon Volume as an Indicator of Outcomes after Carotid Endarterectomy: An Effect Independent of Specialty Practice and Hospital Volume John A Cowan Jr, MD, Justin B Dimick, MD, B Gregory Thompson, MD, James C Stanley, MD, FACS, Gilbert R Upchurch Jr, MD, FACS BACKGROUND: High-volume hospitals have been shown to have superior outcomes after carotid endarterec- tomy (CEA), but the contribution of surgeon volume and specialty practice to CEA outcomes in a national sample is unknown. STUDY DESIGN: Using the National Inpatient Sample for 1996 and 1997, 35,821 patients who underwent CEA (ICD-9-CM code 3812) and had data for unique surgeon identification were studied. Surgeons were categorized in terms of annual CEA volume as low-volume surgeons ( 10 procedures), medium-volume surgeons (10 to 29), and high-volume surgeons ( 30). Data from cardiac, general, neurologic, and vascular surgical practices were analyzed. In-hospital mortality, post- operative stroke, and prolonged length of stay ( 4 days) were the primary outcomes variables. Unadjusted and case-mix adjusted analyses were performed. RESULTS: The overall in-hospital mortality was 0.61%. CEA was performed annually by high-volume surgeons in 52% of patients, by medium-volume surgeons in 30% of patients, and by low- volume surgeons in 18% of patients. Observed mortality by surgeon volume was 0.44% for high-volume surgeons, 0.63% for medium-volume surgeons, and 1.1% for low-volume sur- geons (p  0.001). The postoperative stroke rate was 1.14% for high-volume surgeons, 1.63% for medium-volume surgeons, and 2.03% for low-volume surgeons (p  0.001). Surgeon specialty had no statistically significant effect on mortality or postoperative stroke. In the logistic regression model, increased risk of mortality was associated with emergent admission (odds ratio [OR] = 2.1; 95% confidence interval [CI] 1.6 to 2.8, p  0.001), patient age  65 years (OR = 2.0; 95% CI 1.3 to 3.1, p = 0.001), low-volume surgeon (OR = 1.9; 95% CI 1.4 to 2.5, p  0.001), and COPD (OR = 1.8; 95% CI 1.3 to 2.5, p = 0.001). Low hospital CEA volume ( 100) was not a significant risk factor in the multivariate analysis. CONCLUSIONS: More than 50% of the CEAs in the United States are performed by high-volume surgeons with superior outcomes. Health policy efforts should focus on reducing the number of low-volume surgeons, regardless of surgeon specialty or total hospital CEA volume. ( J Am Coll Surg 2002; 195:814–821. © 2002 by the American College of Surgeons) Carotid endarterectomy (CEA) is the preferred treat- ment for symptomatic and critically stenotic extracra- nial carotid artery disease. To realize the benefits of CEA, postoperative mortality and stroke must be mini- mized. 1,2 Numerous provider-dependent variables, in- cluding operative technique, intraoperative monitoring, and hospital and surgeon caseloads, have been studied in attempts to define the most optimal outcomes after CEA. It has been argued that low-volume hospitals do not enjoy the same outcomes in large multicenter trials 3-5 or those reported at high-volume hospitals. 2 One con- clusion is that CEA should be performed at select high- volume centers. 6,7 The implementation of such a policy remains controversial. National data would suggest that nearly 150,000 CEAs are performed annually by members of at least four different surgical specialties. 8 The influence of sur- geon volume and specialty practice on CEA outcomes No competing interests declared. This work was presented at the 63 rd Annual Meeting of the Society of Uni- versity Surgeons, Residents’ Forum, Honolulu, HI, February 2002. Received March 20, 2002; Revised July 10, 2002; Accepted July 15, 2002. From the Departments of Neurosurgery (Cowan, Thompson) and Surgery (Dimick, Stanley, Upchurch), University of Michigan Medical Center, Ann Arbor, MI. Correspondence address: Gilbert R Upchurch Jr, MD, 1500 East Medical Center Dr, Taubman Center 2210, Ann Arbor, MI 48109-0329. 814 © 2002 by the American College of Surgeons ISSN 1072-7515/02/$21.00 Published by Elsevier Science Inc. PII S1072-7515(02)01345-5