Patients with minor ischemic stroke or high-risk transient ischemic attack (TIA) face elevated early recurrent vascular event risks, with guidelines recommending short-term dual antiplatelet therapy (DAPT) with aspirin and clopidogrel initiated promptly. However, real-world data on the impact of initiation timing remain limited, particularly beyond the hyperacute phase.
This retrospective analysis utilized data from a nationwide multicenter stroke registry encompassing 20 centers from January 2011 to April 2023. Included were 41,530 adults with minor noncardioembolic ischemic stroke (National Institutes of Health Stroke Scale [NIHSS] score ≤5) or high-risk TIA who presented within 7 days of symptom onset. Patients were stratified by in-hospital antiplatelet regimen: DAPT (aspirin plus clopidogrel) versus monotherapy (aspirin or clopidogrel alone). The primary outcome was a composite of recurrent stroke, myocardial infarction, or vascular death at 90 days. Secondary outcomes included individual ischemic events and safety endpoints such as major bleeding. Adjusted hazard ratios were calculated using multivariable Cox regression, with subgroup analyses by time from symptom onset to hospital arrival and DAPT initiation.
Of the cohort, 25,112 patients (60.5%) received in-hospital DAPT. Overall, DAPT was associated with a lower risk of the primary outcome (10.7% vs. 11.6%; adjusted HR 0.82, 95% CI 0.77–0.87) compared to monotherapy. The benefit was most pronounced in patients arriving within 24 hours, where early DAPT initiation yielded the strongest risk reduction (adjusted HR 0.74, 95% CI 0.69–0.79). Efficacy waned progressively with delayed initiation, becoming nonsignificant beyond approximately 42 hours post-onset. No significant increase in major bleeding was observed with early DAPT, though overall bleeding rates were low.
In this large, representative real-world cohort, early in-hospital DAPT initiation—particularly within the first 24 hours—was consistently linked to improved 90-day vascular outcomes in patients with minor stroke or high-risk TIA. These results underscore the time-dependent nature of DAPT efficacy, supporting urgent administration as emphasized in current guidelines while suggesting limited benefit from delayed therapy. Further prospective studies are needed to refine optimal timing thresholds and personalize treatment based on patient risk profiles.
Link: https://www.ahajournals.org/doi/10.1161/STROKEAHA.125.053343
