Safety of antiplatelet therapy prior to intravenous thrombolysis in acute ischemic stroke

Background: There is some uncertainty whether prior use of antiplatelet (AP) drugs increases the risk of symptomatic intracerebral hemorrhage (SICH) and influences functional outcome in patients with ischemic stroke treated with intravenous thrombolysis. Objective: To assess whether prior use of AP drugs is related to outcome following intravenous tissue plasminogen activator therapy in patients with ischemic stroke. Design, Setting, and Patients: A single-center prospective observational cohort study of the relation between prior AP therapy, occurrence of SICH, and functional outcome of consecutive patients with ischemic stroke undergoing intravenous thrombolysis with tissue plasminogen activator in a university hospital between April 1, 2002, and November 30, 2006. Main Outcome Measures: The occurrence of SICH and favorable outcome reflecting independence defined as a modified Rankin Scale score of 2 or lower at 3 months. Results: Of the 301 patients who received intravenous tissue plasminogen activator, 89 used AP drugs prior to thrombolysis. Symptomatic intracerebral hemorrhage occurred in 12 patients (13.5%; 95% confidence interval, 7.8%-22.3%) who had received AP drugs and in 6 patients (2.8%; 95% confidence interval, 1.2%-6.2%) without prior AP therapy (P=.001). Multivariate analysis revealed that prior AP therapy was an independent predictor of SICH (odds ratio, 6.0; 95% confidence interval, 2.0-17.1). Nonetheless, prior AP therapy was independently associated with a favorable outcome (odds ratio, 2.0; 95% confidence interval, 1.0-4.3). Conclusion: Despite a higher incidence of SICH, the net benefit of intravenous tissue plasminogen activator therapy for acute ischemic stroke was greater in patients using AP drugs.