Rothman, Andrew

Introduction: The relative performance of carotid artery stenting (CAS) and carotid endarterectomy (CEA) among Medicare beneficiaries in routine clinical practice has not been established. Objective: To compare the performance of CAS relative to CEA among Medicare beneficiaries. Methods: We linked Medicare data (2000-2009) to the Society for Vascular Surgery’s Vascular Registry (SVS-VR; 2005-2008) and to the NCDR® Carotid Artery Revascularization and Endarterectomy Registry (CARE; 2006-2008/9). Medicare patients aged ≥66 years undergoing CAS or CEA were followed from the procedure date for the outcomes of death, stroke/transient ischemic attack (TIA), peri-procedural myocardial infarction (MI) or a composite endpoint for these outcomes. We derived high-dimensional propensity scores using registry and Medicare data to control for patient-level factors and adjusted for provider-level factors including past-year CAS/CEA physician and hospital volume, hospital ownership, teaching affiliation, and hospital size in a Cox regression model comparing CAS to CEA. Results: Among 5,254 SVS-VR (1,999 CAS and 3,255 CEA) and 4,055 CARE (2,824 CAS and 1,231 CEA) patients, CAS patients were more often at higher surgical risk (SVS-VR: 96.7% vs. 44.5%; CARE: 71.3% vs. 44.7%) and had a higher comorbidity burden. Crude outcome risks for death and stroke/TIA were lower for CEA. Adjusting for patient-level factors drove estimates downwards for CAS relative to CEA but only after further adjustment for provider-level factors did the performance of CAS and CEA become comparable on all outcomes (figure 1). Conclusion: Performance of CAS and CEA among Medicare beneficiaries was comparable after accounting for patient- and provider-level factors, which is consistent with landmark trials. Further studies are needed to understand the role of heterogeneity in provider-level characteristics.