Abstract WP21: Intravenous Alteplase for Unknown Onset Stroke on Prior Antiplatelet Therapy: EOS Individual Participant Data

Abstract

Introduction: Although prior antiplatelet therapy (APT) could potentially contribute to bleeding risk, the influence of prior APT on intravenous thrombolysis outcomes remains controversial. We sought to assess the efficacy and safety of intravenous thrombolysis for acute ischemic stroke in patients receiving prior APT Methods: Patients with an acute stroke of unknown onset were evaluated using an individual patient-level database of randomized controlled trials comparing t-PA with placebo or standard care from the Evaluation of Unknown Onset Stroke Thrombolysis (EOS) trials. A favorable outcome was defined as a modified Rankin Scale of 0 to 1 at 90-days. Safety outcomes included symptomatic intracranial hemorrhage (sICH) at 22 to 36 hours and 90-day mortality. Results: Baseline data on prior APT were available for 780 of 843 patients. Of these, 257 (32.9%) patients were receiving prior APT. Patients with prior APT were older (72 vs. 66 years), and had a higher prevalence of vascular risk factors than those without APT. Overall, there was no interaction between prior APT and treatment effects of alteplase (p interaction=0.23). A favorable outcome was observed in 55 of 125 (45%) patients with prior APT in the alteplase group and in 39 of 132 (30%) patients with prior APT in the control group (adjusted odds ratio [aOR], 2.41 [95% CI, 1.14-5.13]). sICH occurred in 7 patients (5.6%) in the alteplase group but in 1 patient (0.8%) of the controls (aOR, 10.82 [0.63-185.3]). 90-day mortality was observed in 6 patients (6.5%) in the alteplase group compared with 6 patients (6.1%) in the controls (aOR, 1.47 [0.25-8.78]). In patients without prior APT (n=523), favorable outcome was observed in 136 patients (51.3%) in the alteplase group and in 112 patients (45.3%) in the control group (aOR, 1.38 [0.90-2.11]). Additionally, no significant differences were found in terms of safety outcomes between the two groups (sICH: 3 [1.2%] vs. 1 [0.4%]; mortality: 13 [4.9%] vs. 3 [1.1%]). Conclusion: Intravenous alteplase exhibited efficacy for acute stroke without increasing the risks of symptomatic intracranial hemorrhage or mortality in patients with prior antiplatelet therapy.