Background and Purpose
Evidence indicates that center volume of cases affects outcomes for both carotid endarterectomy (CEA) and stenting (CAS). We evaluated the effect of enrollment volume by site on complication rates in the Carotid Revascularization Endarterectomy versus Stenting Trial (CREST).
Methods
The primary composite endpoint was any stroke, myocardial infarction, or death within 30 days or ipsilateral stroke in follow-up. The 477 approved surgeons performed >12 procedures per year with complication rates <3% for asymptomatic patients and <5% for symptomatic patients; 224 interventionists were certified after a rigorous two step credentialing process. CREST centers were divided into tertiles based on the number of patients enrolled into the study, with Group 1 sites enrolling <25 patients, Group 2 sites enrolling 25–51 patients and Group 3 sites enrolling >51 patients. Differences in periprocedural event rates for the primary composite endpoint and its components were compared using logistic regression adjusting for age, sex, and symptomatic status within site-volume level.
Results
The safety of CAS and CEA did not vary by site-volume during the periprocedural period as indicated by occurrence of the primary endpoint (p=0.54) or by stroke and death (p=0.87). A trend towards an inverse relationship between center enrollment volume and complications was mitigated by adjustment for known risk factors.
Conclusions
Complication rates were low in CREST and were not associated with center enrollment volume. The data are consistent with the value of rigorous training and credentialing in trials evaluating endovascular devices and surgical procedures.