Hidden Readmissions after Carotid Endarterectomy and Stenting

Background: Historically, carotid procedures incur a readmission rate of approximately 6%; however, these studies are not nationally representative and are limited to tracking only the index hospitals. We sought to evaluate a nationally representative database for readmission rates (including different hospitals) after both carotid endarterectomy (CEA) and carotid artery stenting (CAS) and determine risk factors for poor outcomes including postoperative mortality and myocardial infarction.Methods: This study was a retrospective analysis utilizing the 2010-2014 Nationwide Readmissions Database to query patients aged >18 years undergoing CEA or CAS. Outcomes included initial admission mortality, and 30-day readmission, including mortality and myocardial infarction (MI). Univariable analysis of 39 demographic, clinical, and hospital variables was conducted with significance set at P < 0.05. Significant variables were included in a multivariable logistic regression to identify independent risk factors for readmission.Results were weighted for national estimates. Results: There were 527,622 patients undergoing carotid procedures and 13% (n = 69,187) underwent CAS. The 30-day readmission rate was 7% (n = 35,782), and of those, 25% (n = 8,862) were readmitted to a different hospital. When controlling for other factors, CAS was a risk factor for mortality at both index admission (odds ratio [OR] 2.29 [2.11-2.49]) and 30-day readmission (OR 1.48 [1.3-1.69]) and 30-day readmissions at both index hospital (OR 1.11 [1.07-1.14]) and different hospital (OR 1.38 [1.29-1.48]). Readmission to a different hospital increased mortality risk (OR 1.45 [1.29-1.63]) but did not have an effect on MI. Post-operative infections comprised 15% of readmissions while 6% of all readmissions were for stroke.Conclusions: Previously unreported, one in 4 readmissions after carotid procedures occur at a different hospital and this fragmentation of care could increase mortality risk after carotid procedures particularly for CAS which was also an independent risk factor for postoperative mortality and readmissions. Further validation is required to decrease unnecessary hospital after carotid procedures.