LAUSR

Objectives: The unplanned readmission rate after carotid procedures is approximately 6%, but most prior studies are limited to only index hospital readmission. Up to one in three postoperative readmissions occur at a different hospital and are missed by current metrics. There are no national studies examining readmission after carotid endarterectomy and carotid artery stenting (CAS), including to different hospitals. The purpose of this study was to compare unplanned readmission incidence and risk factors between carotid endarterectomy and CAS, including readmissions to any hospital, in a nationally representative sample. Methods: The 2010 through 2014 Nationwide Readmissions Database was queried for all patients undergoing carotid endarterectomy or CAS. Outcomes included postprocedure stroke (cerebrovascular accident), 30-day readmission, and mortality during initial admission or 30-day readmission. A univariable analysis of 39 demographic, clinical, and hospital variables was conducted with significance set at P < .05. Significant variables were included in a multivariable logistic regression to identify risk factors for readmission. Results were weighted for national estimates. Results: There were 527,622 patients who underwent carotid procedures and 13.1% (n 1⁄4 69,187) who underwent CAS. The 30-day readmission rate was 6.8% (n 1⁄4 35,782) and, of those, 24.8% (n 1⁄4 8,862) were readmitted to a different hospital. When controlling for other factors, readmission to a different hospital increased mortality risk (odds ratio [OR], 1.45; 95% confidence interval [CI], 1.29-1.63; P < .01). Risk factors for 30-day readmission to a different hospital included elective initial admission (OR, 1.43; 95% CI, 1.36-1.51; P < .01), Medicaid (1.29; 95% CI, 1.13-1.47; P < .01), Medicare (1.21; 95% CI, 1.12-1.31; P < .01), and Charlson Comorbidity Index score of 2 (OR, 1.09; 95% CI, 1.02-1.16; P 1⁄4 .01). CAS was a risk factor for readmission (OR, 1.11; 95% CI, 1.07-1.14; P < .01) and readmission to a different hospital (OR, 1.38; 95% CI, 1.29-1.48; P < .01). CAS was also a risk factor for postoperative cerebrovascular accident on admission (OR, 1.29; 95% CI, 1.191.38; P < .01) and readmission (OR, 1.49; 95% CI, 1.37-1.62; P < .01). Conclusions: Previously unreported, one in four readmissions after carotid procedures occur at a different hospital. This fragmentation of care increases mortality risk. Readmission after CAS in particular is underestimated. Patient counseling using current risk data is possibly flawed. There are significant implications for clinical decision making, outcomes measurement, benchmarking, and quality assessment.