Risk of recurrent stroke and antiplatelet choice in breakthrough stroke while on aspirin

Uncertainty regarding an optimal antiplatelet regimen still exists in patients with breakthrough acute ischemic stroke (AIS) while on aspirin. This study provides an analysis of a prospective multicenter registry between April 2008 and April 2014. Eligible patients were on aspirin at the time of AIS and treated with antiplatelet regimens (aspirin, clopidogrel, or clopidogrel-aspirin). Potential factors associated with the choice of each antiplatelet regimen were explored and included a predictive risk score for future vascular events, the Essen Stroke Risk Score (ESRS). A total of 2348 patients (age, 69 ± 11 years; male, 57.7%) were analyzed, and 55.3%, 25.3% and 19.4% were treated with clopidogrel-aspirin, aspirin and clopidogrel, respectively. While the likelihood of choosing clopidogrel-aspirin increased as the ESRS increased, the likelihood of choosing aspirin decreased as the ESRS increased (P_trend < 0.001). The ESRS category (0-1/2-3/ ≥ 4) modified the effect of antiplatelet regimens for 1-year vascular events (P_interaction < 0.01). Among patients with ESRS ≥ 4, clopidogrel-aspirin (HR 0.47 [0.30-0.74]) and clopidogrel (HR 0.30 [0.15-0.60]) significantly reduced the risk of outcome events. Our study showed that more than half of the patients with aspirin failure were treated with clopidogrel-aspirin. In particular, a higher ESRS, which indicates an increased risk of recurrent stroke, was associated with the choice of clopidogrel-aspirin rather than aspirin.