Platelet Function Test-Guided Antiplatelet Therapy Reduces Recurrent Stroke in Atherothrombotic and Lacunar Infarction

Bakground and Purpose Antiplatelet resistance is a recognized risk factor for recurrent ischemic stroke, yet evidence supporting platelet function test?guided antiplatelet therapy modification in stroke prevention remains limited. We investigated whether VerifyNow-guided antiplatelet therapy modification reduces recurrent ischemic stroke in patients with atherothrombotic or lacunar infarction. Methods This retrospective observational study enrolled consecutive patients with atherothrombotic or lacunar infarction at a single center (April 2023-March 2025). Of 302 patients, 243 were analyzed: 122 in the modified group, whose antiplatelet agent was selected based on VerifyNow Aspirin Reaction Units and P2Y12 Reaction Units, and 121 in the unmodified group, whose agent was empirically selected. The mean follow-up period was 1.62 {+/-} 0.61 years. In the modified group, when both aspirin and clopidogrel showed inadequate inhibition, prasugrel or cilostazol was selected. The primary endpoint was recurrent ischemic stroke; the secondary endpoint was intracranial hemorrhage. Cox proportional hazards models with inverse probability weighting were used to adjust for confounders. Results Recurrent ischemic stroke occurred in 1 patient (0.8%) in the modified group versus 8 (6.6%) in the unmodified group (log-rank P=0.018). After adjustment, the modified group had a significantly lower risk of recurrent stroke (HR, 0.10; 95% CI, 0.012-0.84; P=0.033). Intracranial hemorrhage occurred in 0 (0%) and 1 (0.8%) patients, respectively. Conclusions In Japanese patients with atherothrombotic or lacunar infarction, VerifyNow-guided antiplatelet therapy modification was associated with a significantly lower incidence of recurrent ischemic stroke without increased hemorrhagic risk. Given the single-center retrospective design and small sample size, validation in a multicenter randomized controlled trial is warranted.