Introduction: Hospital volume may influence the outcomes of carotid revascularization, but in trials the effect of the clinical experience of individual surgeons on procedural outcome is less certain. We assessed perioperative event rates amongst centers with different trial entry volumes and also the effects of individual operator experience in the first Asymptomatic Carotid Surgery Trial-1 (ACST-1). Methods: In 126 centers participating in ACST-1, surgeons were classified according to their in-trial experience (group A: 50 cases; group B: 51-100 cases; group C: >100 cases), center enrolment volume (group I: <30 patients; group II: 30-75 patients; group III: >75 patients) and center annual hospital volume (group 1: <40 carotid endarterectomies (CEAs); group 2: 40-75 CEAs; group 3: >75 cases). Differences in perioperative event rates were compared using logistic regression analysis. Results: In centers with the most clinical experience compared with those with least experience (groups C vs. A), the number of strokes or deaths was 8 of 275 (2.9%) versus 24 of 810 (3.0%) with OR 0.99 (95% CI 0.44-2.25, p = 0.986). Numbers of strokes or death in high enrolment centers compared with those in low enrolment centers (groups III vs. I) was 20 of 680 (2.9%) versus 21 of 580 (3.6%) with OR 0.81 (95% CI 0.43-1.51, p = 0.921). In centers with a high annual volume compared with those of low annual volume (groups 3 vs. 1), numbers of strokes and death were non-significantly lower, 26 of 823 (3.2%) versus 19 of 422 (4.5%) with OR 0.68 (95% CI 0.37-1.26, p = 0.386). Cumulative stroke risk at 5 and 10 years were similar among different levels of reported clinical experience, enrolment volume and annual hospital volume. Conclusion: Although our data did not demonstrate an association between perioperative complications and operators' experience, enrolment volume or annual hospital volume, rates of stroke or death were numerically lower in both high enrolment and high annual volume centers. This lack of association could be explained by an overall low procedural risk in ACST-1.

Halliday A, Harrison M, Hayter E, et al: 10-year stroke prevention after successful carotid endarterectomy for asymptomatic stenosis (ACST-1): a multicentre randomised trial. Lancet 2010;376:1074-1084.
Endarterectomy for asymptomatic carotid artery stenosis. Executive committee for the asymptomatic carotid atherosclerosis study. JAMA 1995;273:1421-1428.
Archie JP Jr: Learning curve for carotid endarterectomy. South Med J 1988;81:707-710.
Holt PJ, Poloniecki JD, Loftus IM, et al: Meta-analysis and systematic review of the relationship between hospital volume and outcome following carotid endarterectomy. Eur J Vasc Endovasc Surg 2007;33:645-651.
Fiehler J, Jansen O, Berger J, et al: Differences in complication rates among the centres in the SPACE study. Neuroradiology 2008;50:1049-1053.
Gonzales NR, Demaerschalk BM, Voeks JH, et al: Complication rates and center enrollment volume in the carotid revascularization endarterectomy versus stenting trial. Stroke 2014;45:3320-3324.
Halliday AW, Thomas D, Mansfield A: The asymptomatic carotid surgery trial (ACST). Rationale and design. Steering committee. Eur J Vasc Surg 1994;8:703-710.
Caldwell K, Koch S, Khan I, et al: Impact of surgical specialty and operator experience on outcomes following carotid endarterectomy. J Vasc Surg 2015;61:577-578.
Rerkasem K, Rothwell PM: Patch angioplasty versus primary closure for carotid endarterectomy. Cochrane Database Syst Rev 2009;4:CD000160.
Rerkasem K, Rothwell PM: Routine or selective carotid artery shunting for carotid endarterectomy (and different methods of monitoring in selective shunting). Cochrane Database Syst Rev 2009;4:CD000190.
De Borst GJ, Moll FL: Evidence overview for shunting, patching, type of endarterectomy and anesthesia during carotid surgery. J Cardiovasc Surg (Torino) 2014;55(2 suppl 1):1-9.
Eliasziw M, Rankin RN, Fox AJ, et al: Accuracy and prognostic consequences of ultrasonography in identifying severe carotid artery stenosis. North American symptomatic carotid endarterectomy trial (NASCET) group. Stroke 1995;26:1747-1752.
Wennberg DE, Lucas FL, Birkmeyer JD, et al: Variation in carotid endarterectomy mortality in the Medicare population: trial hospitals, volume, and patient characteristics. JAMA 1998;279:1278-1281.
Kakisis JD, Avgerinos ED, Antonopoulos CN, et al: The European society for vascular surgery guidelines for carotid intervention: an updated independent assessment and literature review. Eur J Vasc Endovasc Surg 2012;44:238-243.
Brott TG, Halperin JL, Abbara S, et al: ASA/ACCF/AHA/AANN/AANS/ACR/ASNR/CNS/SAIP/SCAI/SIR/SNIS/SVM/SVS guideline on the management of patients with extracranial carotid and vertebral artery disease: executive summary. A report of the American College of Cardiology Foundation/American Heart. Circulation 2011;124:489-532.
Cowan JA Jr, Dimick JB, Thompson BG, et al: Surgeon volume as an indicator of outcomes after carotid endarterectomy: an effect independent of specialty practice and hospital volume. J AM Coll Surg 2002;195:814-821.
Mas JL, Chatellier G, Beyssen B, et al: Endarterectomy versus stenting in patients with symptomatic severe carotid stenosis. N Engl J Med 2006;355:1660-1671.
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