Abstract TP168: Risk of Stroke and Hemorrhage in Patients Treated With Warfarin Versus Dabigatran Requiring Surgery

Abstract

Introduction: Patients with atrial fibrillation (AF) cease anticoagulants prior to surgery to minimize bleeding risk. Patients requiring emergency surgery may be particularly vulnerable to bleeding if anticoagulants remain in the blood. This may be especially problematic with dabigatran (DAB) use given its lack of reversal agent. Objective: This study compares stroke or bleeding risk in patients with AF taking DAB or warfarin (WARF) that undergo elective, urgent, or emergent inpatient surgery. Methods: Medicare inpatient claims were used to identify patients with AF who underwent elective (n=20,535) and urgent or emergent (n=24,665) surgery from 11/2010 -12/2012, and had received DAB or WARF within 90 days prior to admission. Outcomes included stroke and major bleeding within 30 days of surgery, and blood units used during the admission. Other patient characteristics included demographics, operation type, and comorbid conditions. Risk adjusted differences in outcomes between patients taking DAB or WARF were estimated within admission category using multivariable regression. Results: DAB was used by 5,495 (12%) of patients prior to admission. Overall, 1.0% of patients had stroke within 30 days of surgery, 1.2% had a major bleeding event, and patients received an average 0.12 units of blood. Stroke and bleeding rates did not differ for patients taking WARF or DAB, overall or within admission category. Among elective admissions, blood units used also did not differ between WARF or DAB patients. Among urgent and emergent admissions, patients taking DAB used significantly fewer blood units than patients taking WARF (0.09 vs 0.18, respectively; p<.001). Results were consistent after controlling for other patient factors in multivariable models. Conclusions: Stroke and bleeding risk in patients taking either DAB or WARF were comparable, while patients taking DAB required significantly fewer blood units than patients taking WARF when undergoing emergency surgery. The lack of a reversal agent for DAB does not appear to increase the risk of complications even for emergency surgery.