Multiple antiplatelet therapy in ischemic stroke already on antiplatelet agents

Abstract Background: Optimal antiplatelet strategy for patients with ischemic stroke who were already on single antiplatelet therapy (SAPT) remains to be elucidated. This study aimed to evaluate the effect of different antiplatelet regimens on vascular and safety outcomes at 1 year after non-cardioembolic stroke in patients previously on SAPT. Methods: We identified 9,284 patients with acute non-cardioembolic ischemic stroke that occurred on SAPT using linked data. Patients were categorized into three groups according to antiplatelet strategy at discharge: 1) SAPT, 2) dual antiplatelet therapy (DAPT), and 3) triple antiplatelet therapy (TAPT). One-year outcomes included recurrent ischemic stroke, composite outcomes (recurrent ischemic stroke, myocardial infarction, intracerebral hemorrhage, and death), and major bleeding. Results: Of 9,284 patients, 5,565 (59.9%) maintained SAPT, 3,638 (39.2%) were treated with DAPT, and 81 (0.9%) were treated with TAPT. Multiple antiplatelet therapy did not reduce the risks of 1-year recurrent stroke (DAPT, hazard ratio [HR] 1.08 [95%confidence interval, CI, 0.92–1.27], P= 0.339; TAPT, HR, 0.71 [95%CI, 0.27–1.91], P = 0.500) and 1-year composite outcome (DAPT, HR, 1.09 [95%CI, 0.68–1.97], P = 0.592; TAPT HR, 1.46 [95%CI, 0.68–1.97], P = 0.592). However, the TAPT groups showed an increased risk of major bleeding complications (DAPT, HR, 1.23 [95%CI, 0.89–1.71], P = 0.208; TAPT, HR, 4.65 [95%CI, 2.01–10.74], P < 0.001). Conclusions: Additional use of antiplatelet agents in patients with non-cardioembolic ischemic stroke who were already on SAPT did not reduce the 1-year incidence of vascular outcomes, although it increased the risk of bleeding complications.