Abstract 186: Regional Variation in Carotid Revascularization Procedures and Outcomes Among Elderly Medicare Beneficiaries

Background: Carotid endarterectomy (CEA) and carotid artery stenting (CAS) are the most frequently performed revascularization procedures to prevent stroke. Little is known about national geographic patterns and outcomes for the two procedures. We evaluated geographic variation in the performance of CEA and CAS and 30-day post-procedure outcomes (ischemic stroke or death, all-cause mortality, all-cause readmission). Methods: Fee-for-service Medicare beneficiaries aged ≥65 years who underwent CEA or CAS from 2012-2014 were identified using ICD-9 procedure codes. Spatial mixed models with a Poisson link function and adjustment for demographics were used to calculate and map county-specific risk-standardized rates of carotid revascularization. We used mixed models and Cox regression to assess the relationship between region and 30-day outcomes, adjusting for demographics, symptomatic status, and comorbidities. Results: Between 2012 and 2014, 112,995 patients had a CEA (mean age 75.6y; 41.6% women) and 34,075 had CAS (mean age 75.2y; 45.7% women). The county-level risk-standardized rates per 100,000 beneficiary-years ranged from 51-248 for CEA and from 0-317 for CAS. Although the highest CEA rates were in the Midwest and South, there were pockets of high CAS rates across the country. There was no correlation between county-level rates of CEA and CAS (weighted Pearson’s r=0.011; p=0.525). In analyses stratified by age, there was no difference in the regional patterns of carotid revascularization for those aged 65-69y vs ≥70y. Compared with the Northeast, the South had worse outcomes after CEA but better outcomes after CAS, and the Midwest had better outcomes after CAS. Conclusion: There were differences in regional patterns of the performance of CEA and CAS and post-procedure outcomes among elderly Medicare beneficiaries. Factors contributing to geographic disparities in performance and differences in outcomes across regions require further study.