Abstract WP74: Influence of Antiplatelet Pre-treatment on Platelet Function and Clinical Outcomes After Intravenous Trombolysis in Stroke Patients

Background and aims: There May be a link between platelet function and clinical outcomes in acute stroke patients with intravenous thrombolysis. We aimed to compare dynamic change of maximum platelet aggregation (MPA) in 24 hours after thrombolysis and outcomes between patients naïve to antiplatelet therapy (AP) and those with prior AP. Methods: We conducted a prospective study on acute stroke patients who received intravenous recombinant tissue plasminogen activator (rt-PA). The patients were divided based on whether to have prior AP or not. Five venous blood samples were collected: on admission before thrombolysis (baseline); at 3h, 6h, 12h and 18h after thrombolysis. MPA was determined using light transmittance aggregometry (LPA), and agonists tested were arachidonic acid (AA) and adenosine diphosphate (ADP). The outcomes were NIHSS on 1 hour, 24 hours and 7 days after thrombolysis, symptomatic intracerebral hemorrhage (sICH) in 36 hours, mortality in 1 month, mRS in 1 month, 3 month, 6 month and 1 year. Result: Of a total of 58 patients, 23 were pretreated with AP. They achieved significant reduction of AA-induced aggregation on 3 hours, 6 hours, 12 hours, 18 hours after thrombolysis compared with those naïve to AP (P<0.05). There were not significant differences on sICH, mortality, good outcomes (mRS≤2) on 1 month and 3 months (P>0.05). A good long-term outcomes (mRS≤2) on 6 month and 1 year was detected in those naïve to AP (P<0.05). Conclusion: Prior AP may decrease MPA and have an impact on long-term functional outcomes, although it did not increase the risk of sICH and mortality.