Meta-Analysis of Usefulness of Antiplatelet Therapy in Ischemic Stroke or Transient Ischemic Attack

The efficacy of early administration of dual antiplatelet therapy (DAPT) for secondary prevention after acute ischemic stroke or transient ischemic attack (TIA) is uncertain. This systematic review and meta-analysis compares the safety and efficacy of early administration (<24 hours) of DAPT (using either clopidogrel or ticagrelor with aspirin) versus single antiplatelet therapy (SAPT; aspirin alone) in acute non-cardioembolic ischemic stroke or TIA, incorporating data from large randomized controlled trials. Published trials fulfilling our criteria were identified from an electronic search of MEDLINE, with key words including: "clopidogrel or ticagrelor", "aspirin", "ischemic stroke", "transient ischemic attack", and "randomized controlled trial". Included were 3 randomized controlled trials of 21,067 patients assessing early administration (<24 hours from symptom onset) of DAPT versus SAPT in non-cardioembolic acute ischemic stroke or TIA. Our efficacy outcomes were ischemic stroke and all-cause mortality. Our safety outcome was severe bleeding. We performed a meta-analysis to pool results with a hierarchical Bayesian random-effects model. Dual antiplatelet therapy significantly reduced the risk of ischemic stroke (hazard ratio [HR], 0.73; 95% credible interval [CrI]: 0.54, 0.97), while increasing the risk of severe bleeding (HR, 2.48; 95% CrI: 1.07, 5.26). There was a non-significant numerical trend toward increased mortality with DAPT (HR, 1.29; 95% CrI: 0.73, 2.23). These observations were robust under the sensitivity analysis. In the present systematic review and meta-analysis of randomized controlled trials, DAPT reduced the risk of ischemic stroke at the cost of an increase in severe bleeding. Additional trials examining the ideal timing of DAPT administration are needed to thoroughly investigate the role, if any, of routine DAPT in patients with non-cardioembolic ischemic stroke or high-risk TIA.