Abstract 7: Risk of Intracranial Hemorrhage Among Acute Ischemic Stroke Patients Receiving Prior Antiplatelet Therapy and Treated with Intravenous Tissue Plasminogen Activator

Abstract

Background: Intravenous tissue plasminogen activator (tPA) is known to improve outcomes in ischemic stroke. However, patients receiving long-term antiplatelet therapy may face an increased risk of symptomatic intracranial hemorrhage (sICH) when treated with tPA. While current guidelines allow use of tPA in patients on antiplatelet therapy, there are limited data on the safety of tPA in this population. Methods: Data from 51,922 ischemic stroke patients treated with tPA within 4.5 hours of symptom onset from 1,401 Get With The Guidelines-Stroke hospitals between January 2009 and June 2013 were analyzed. Multivariate logistic regression model with generalized estimating equations approach was performed to evaluate the association of preadmission antiplatelet therapy on sICH risk. Results: Of tPA treated patients 23,232 (45%) were receiving antiplatelet medicine prior to admission. Patients on prior antiplatelet therapy were older (median 76 vs. 68 years, p<.001), had more comorbid illness (CAD/prior MI, prior stroke/TIA, atrial fibrillation, diabetes, dyslipidemia, hypertension and heart failure, all p <.001) but had similar stroke severity (median National Institutes of Health Stroke Scale [NIHSS] 10 vs. 10, p=0.07). Crude rates of sICH were higher in those on prior antiplatelet therapy 5.32% vs. 4.03% (unadjusted OR 1.31, 95% CI 1.20-1.43). Multivariate analysis revealed that prior antiplatelet therapy was an independent predictor of sICH (adjusted OR 1.17, 95% CI 1.06-1.29; adjusted sICH rates 4.93% vs. 4.26%), serious systemic hemorrhage or any tPA complications. These findings were consistent in subgroup analysis of 0-3 hour treatment window. However, there were no significant differences between two groups in mortality, discharge to skilled nursing facility or hospice. In contrast, antiplatelet therapy was associated with favorable ambulatory status at discharge after risk adjustment ( Table ). Conclusion: This study represents the largest clinical experience of the safety of thrombolysis in patients on prior antiplatelet therapy. Despite a higher incidence of sICH, the absolute excess risk appears small (0.67%). These findings support current guideline recommendations regarding use of intravenous tPA in patients on antiplatelet therapy with careful weighing of potential risk and benefit.