Abstract 59: Contemporarypre-Stroke Antiplatelet Use and the Risk of Symptomatic Hemorrhagic Transformation After Intravenous Thrombolysis

Abstract

Introduction: Many patients are taking antiplatelet medications when an acute stroke occurs. We evaluated the risk of hemorrhage associated with newer, more potent antiplatelet medications and dual antiplatelet regimens among patients treated with intravenous tissue plasminogen activator (IV-tPA). Methods: Using the American Heart Association Get With The Guidelines-Stroke Registry from January 1, 2013 to December, 31 2021, we analyzed data on all ischemic stroke patients hospitalized and treated with IV-tPA. The exposure of interest was pre-stroke antiplatelet use categorized as none, single (SAPT), and dual antiplatelet therapy (DAPT). The primary outcome of interest was symptomatic intracranial hemorrhage (sICH) within 36 hours of tPA administration. A secondary outcome was modified Rankin Scale (mRS) at discharge. Propensity score matching was performed to mitigate confounding by indication for each pre-stroke antiplatelet treatment strategy. Adjusted multivariate logistic regression analyses were performed to evaluate associations between pre-stroke antiplatelet medication and outcomes of interest. Results: The analytic cohort included 320,493 patients who had an acute ischemic stroke and received IV-tPA. The pre-stroke antiplatelet therapy utilization frequencies were 56.9% no antiplatelet, 36.7% SAPT, and 6.4% DAPT. The frequency of sICH was 2.9%, 3.8%, and 4.1% among patients treated with none, SAPT, and DAPT respectively (p<0.001). After performing propensity score matching, both SAPT (OR 1.13, 95% C.I. 1.08-1.20) and DAPT (OR 1.28, 95% C.I. 1.14-1.43) were associated with increased risks of sICH. DAPT was also associated with a significantly higher risk of sICH compared with SAPT (OR 1.18, 95% C.I. 1.08-1.28). Use of pre-stroke antiplatelet medications was associated with lower odds of discharge mRS < 2 compared to none: (SAPT OR 0.92, 95% C.I. 0.89-0.96; DAPT OR 0.93, 95% C.I. 0.87-0.98). Conclusion: In this study, pre-stroke antiplatelet use was associated with a modest, dose-dependent risk of sICH and functional dependence.