Sooner is better when initiating DAPT after minor stroke or high-risk TIA

Initiating dual antiplatelet therapy (DAPT) within 24 h of onset of a minor ischaemic stroke or transient ischaemic attack (TIA) yields the greatest clinical benefit, with the therapeutic effect declining progressively beyond this period, as shown in a study.

The study included 41,530 patients (mean age 66.3 years, 62 percent male) with minor noncardioembolic ischaemic stroke (NIHSS score ≤5) or high-risk TIA who presented within 7 days of symptom onset. Patients were grouped by time from symptom onset to hospital arrival: 0–24, 24–72, and >72 h.

A composite of recurrent stroke, myocardial infarction, and death within 90 days was the primary outcome, evaluated based on in-hospital initiation of DAPT vs monotherapy (aspirin or clopidogrel alone). Time-to-treatment effects were analysed using Cox proportional hazards models, with inverse probability of treatment weighting based on propensity scores.

Of the patients, 25,112 (60.5 percent) received DAPT. The 90-day primary outcome occurred in 10.7 percent of patients who received DAPT vs 11.6 percent of those who received aspirin or clopidogrel alone (hazard ratio [HR], 0.82, 95 percent confidence interval [CI], 0.77–0.87).

Notably, the benefit of DAPT was most pronounced when initiated within 24 h of symptom onset (HR, 0.74, 95 percent CI, 0.69–0.79). DAPT provided no significant benefit when initiated between 24 and 72 h (HR, 1.00, 95 percent CI, 0.88–1.15), and a trend for a higher risk was observed when DAPT was initiated 72 h (HR, 1.25, 95 percent CI, 1.01–1.55).

Time-dependent analysis showed a benefit crossing the null at around 42 h.