Surgeon Case Volume and 30-Day Mortality After Carotid Endarterectomy Among Contemporary Medicare Beneficiaries

Before and After National Coverage Determination for Carotid Artery Stenting

Hiraku Kumamaru, MD, MPH, ScD;Jessica J. Jalbert, PhD;Louis L. Nguyen, MD, MBA,MPH;Marie D. Gerhard-Herman, MD;Lauren A. Williams, BA;Chih-Ying Chen, PhD;John D. Seeger, PharmD, DrPH;Jun Liu, MD, MPH;Jessica M. Franklin, PhD;Soko Setoguchi, MD, DrPH

Background and Purpose—After the 2005 National Coverage Determination to reimburse carotid artery stenting (CAS) for Medicare beneficiaries, the number of CAS procedures increased and carotid endarterectomy (CEA) decreased. We evaluated trends in surgeons’ past-year CEA case-volume and 30-day mortality after CEA, and their association before and after the National Coverage Determination.

Methods—In a retrospective cohort study of patients undergoing CEA (2001–2008) and CAS (2005–2008) using Medicare data, we described yearly trends of CEA and CAS rates, patient characteristics, and 30-day mortality after CEA. We used logistic regression adjusting for patient- and surgeon-level factors to assess the effect of surgeon case volume on 30-day mortality after CEA.

Results—We identified 454 717 CEA and 27 943 CAS patients. Patients undergoing CEA in recent years were older and had more comorbidities than earlier years. CEA rates per 10 000 beneficiaries declined from 18.1 in 2002 to 12.7 in 2008, whereas median surgeon past-year case-volume declined from 27 to 21. The CAS rates peaked at 2.3 per 10 000 beneficiaries in 2006 but declined to 1.8 in 2008, resulting in declining overall revascularization procedure rates during 2005 to 2008. Thirty day post-CEA mortality was 1.40% (95% confidence interval, 1.34–1.47) in 2001 to 2002 and 1.17% (1.10–1.24) in 2007 to 2008. Surgeon’s past-year case-volume of <10 was associated with higher 30-day mortality consistently during 2001 to 2008.

Conclusions—The rate of CEA procedures decreased substantially during 2001 to 2008, as did surgeon past-year case-volume. The postprocedural mortality in Medicare beneficiaries was high compared with trial patients but somewhat improved over time. Those operated by lower past-year case-volume surgeons had increased mortality.

Stroke.2015;46:1288-1294