Low Dose Aspirin Initiation 18 Hours After Thrombolytic Therapy in Acute Ischemic Stroke.

Objectives: To investigate the safety of administering low-dose aspirin (81 mg) 18 hours after intravenous thrombolytic therapy.

Methods: This is a retrospective cohort investigation. Individuals received either alteplase or tenecteplase for acute ischemic stroke followed by aspirin 81 mg (after follow-up imaging). An institutional change moved follow-up post-thrombolytic CT scans to 18 hours, and qualifying patients were grouped based on whether they received aspirin ≤24 hours or >24 hours. Chart reviews were conducted to assess the primary outcome of new or worsening intracranial hemorrhage, as well as secondary outcomes of change in stroke scale scores at discharge and 3 months, lengths of stay, favorable outcomes at 3 months, hospital readmission, and mortality.

Results: Out of 350 patients screened, 130 qualified for inclusion-50 of whom received aspirin ≤24 hours (mean 21.1 hours, SD±6.2), and 80 who received aspirin >24 hours (mean 34 hours, SD±8.2). Only 1 new intracranial bleed occurred following aspirin administration in the >24-hour group. No statistically significant differences were observed in any of the secondary outcomes, although there was higher mortality (3/50 vs. 2/80, P =0.372) and shorter hospital length of stay (median difference -1.0 day, P =0.0336) in the <24 hours group.

Conclusions: Low-dose aspirin administration sooner than 24 hours following thrombolytic therapy did not increase bleeding events. Sooner aspirin administration after ischemic stroke can potentially enhance the prevention of secondary embolization and did not demonstrate worse clinical outcomes; however, further randomized controlled trials are needed.