Influence of site and operator characteristics on carotid artery stent outcomes: analysis of the CAPTURE 2 (Carotid ACCULINK/ACCUNET Post Approval Trial to Uncover Rare Events) clinical study.

OBJECTIVES: The aim of this study was to analyze the CAPTURE 2 (Carotid ACCULINK/ACCUNET Post Approval Trial to Uncover Rare Events) study for physician- or site-related variables associated with differential outcomes for carotid artery stenting (CAS).

BACKGROUND: The CAPTURE 2 trial is an ongoing, prospective, nonrandomized, independently adjudicated, multicenter clinical study enrolling high-surgical-risk patients undergoing CAS.

METHODS: In this assessment of the CAPTURE 2 study, the American Heart Association carotid endarterectomy guideline limits were used to define acceptable site and physician CAS outcomes; therefore, the resulting population of nonoctogenarian, asymptomatic subjects in this analysis is confined to 3,388 (of the total 5,297) subjects treated at 180 U.S. hospitals by 459 operators between March 2006 and January 2009.

RESULTS: The rates of death, stroke, and myocardial infarction and death and stroke (DS) at 30 days were 3.5% and 3.3%, respectively, for the full CAPTURE 2 study cohort and 2.9% and 2.7%, respectively, for the asymptomatic, nonoctogenarian subgroup. In this subgroup, two-thirds of sites (118 of 180, 66%) had no DS events. Within the remaining sites, an inverse relationship between event rates and hospital patient volume as well as between event rates and individual operator volume was observed. The DS rates trended lower for interventional cardiologists compared with other specialties.

CONCLUSIONS: Outcomes from the largest prospectively gathered, independently adjudicated, multicenter CAS study indicate that CAS can be safely performed in a variety of hospital settings by physicians with various specialties. The most important determinant of perioperative CAS outcomes was both site and operator CAS volume. A threshold of 72 cases was found to be necessary for consistently achieving a DS rate below 3% in this later-phase single arm study; background era and non-study operator experience will affect this determination. (Second Phase of "Carotid RX ACCULINK/RX ACCUNET Post-Approval Trial to Uncover Unanticipated or Rare Events"; NCT00302237).