Abstract 16: Regional Variation in the Physician Case Volume for Carotid Artery Stenting (CAS) vs. Carotid Endarterectomy (CEA)
Background: Inverse relationship between outcome and physician volume has been reported for carotid endarterectomy (CEA) and carotid artery stenting (CAS). After the 2005 National Coverage Determination which reimburses CAS for Medicare beneficiaries, CAS procedures are now performed throughout the US. We hypothesized that CAS are more likely to be performed by low case volume physicians compared to CEA in some areas, causing regional variation in the clinical outcomes.
Methods: We identified inpatient CEA and CAS procedures and performing surgeons in the Medicare claims files 2007/2008. We calculated surgeon volume as the number of CAS or CEA performed in the past 365 days and classified physicians with <9 cases as low volume. We calculated the proportion of CEA and CAS procedures performed by low volume physicians in each hospital referral regions (HRRs), an empirically defined local health care markets, and categorized the HRRs into 5 levels based on the proportion of low volume physician procedures (0-20, 20-40, 40-60, 60-80, 80-100%).
Results: We identified 94838 and 13430 Medicare beneficiaries in 306 and 280 HRRs undergoing CEA and CAS. HRRs with larger number of low volume physicians were more prevalent for CAS than for CEA (median proportion: 0.8 (IQR:0.5-1.0) vs. 0.2 (IQR:0.1-0.3). Decreasing trend of 30-day post procedural death was observed as the proportion of low volume physician procedures decreased for CAS (from 2.6% in 80-100% group to 1.3% in 0-20% group), but not for CEA. This trend persisted after adjustment for patient demographics and baseline comorbidities.
Conclusion: Procedure volume of physicians performing CAS remains low in many regions throughout the US compared to CEA. HRRs with higher proportions of CAS performed by low volume physicians had increased risk of peri-procedural mortality. Dissemination of newly introduced procedures such as CAS may benefit from careful planning of physician selection and regionalization.
Author Disclosures: H. Kumamaru: None. J.J. Jalbert: None. L.L. Nguyen: None. S. Setoguchi: Research Grant; Significant; Johnson & Johnson.
- © 2014 by American Heart Association, Inc.