Abstract 28: Readmissions after Carotid Artery Revascularization in the Medicare Population

Abstract

Introduction: In appropriately selected patients with severe carotid stenosis, carotid revascularization reduces risk of ischemic stroke. Prior clinical research has focused on the efficacy and safety of carotid revascularization, but few investigators have considered readmission as a clinically important outcome. We examined frequency and timing of 30-day readmission following carotid revascularization and assessed differences in 30-day readmission rates between patients undergoing carotid endarterectomy (CEA) and carotid artery stenting (CAS). We also examined whether hospital variation in procedural choice (CEA vs CAS) was associated with differences in hospitals’ risk standardized readmission rates (RSRR). Methods: Medicare administrative claims data were used to identify acute care hospitalizations of CEA and CAS from 2009 to 2011. The outcome of interest was time to first hospital readmission within 30-days of carotid revascularization. Hospitals performing more than 25 carotid interventions were stratified into tertiles by the proportion of CAS cases. RSRRs were derived from hierarchical generalized linear models adjusting for hospital clustering and standardized by unadjusted national readmission rate. Results: Of 180,059 revascularizations from 2,287 hospitals, CEA and CAS were performed in 81.5% and 18.5% of cases, respectively. The unadjusted 30-day readmission rate following carotid revascularization was 9.7% with half of these readmissions occurring by day 9. Crude 30-day readmission rates following CEA and CAS were 9.5% and 10.6%, respectively. In multivariable analysis, risk of readmission after CAS was higher than after CEA (Adjusted OR: 1.13, 95% CI: 1.08 - 1.18, P <0.01). When stratified by tertiles of proportional use of CAS, median 30-day RSRR for hospitals using CAS more frequently were comparable to those of hospitals that used CAS less frequently (Figure 1). Conclusions: Almost 10% of Medicare patients undergoing carotid revascularization were readmitted within 30 days of discharge. Compared with CEA, CAS was associated with higher 30-day readmission rates. However, hospitals’ RSRR did not differ by their proportional use of CAS volume. Efforts to identify readmission risk factors are needed to reduce rates of readmissions following carotid revascularization.