Results of trials of aspirin and dipyridamole combined versus aspirin alone for the secondary prevention of vascular events after ischaemic stroke of presumed arterial origin are inconsistent. Our aim was to resolve this uncertainty.

    We did a randomised controlled trial in which we assigned patients to aspirin (30–325 mg daily) with (n=1363) or    without (n=1376) dipyridamole (200 mg twice daily) within 6 months of a transient ischaemic attack or minor stroke of     presumed arterial origin.Our primary outcome event was the composite of death from all vascular causes, non-fatal stroke, non-fatal myocardial infarction, or major bleeding complication, whichever happened first. Treatment was open, but       auditing of outcome events was blinded. Primary analysis was by intention to treat. This study is registered as an       International Standard Randomised Controlled Trial (number ISRCTN73824458) and with ClinicalTrials.gov (NCT00161070).

    Mean follow-up was 3.5 years (SD 2.0). Median aspirin dose was 75 mg in both treatment groups (range 30–325);       extended-release dipyridamole was used by 83% (n=1131) of patients on the combination regimen. Primary outcome events    arose in 173 (13%) patients on aspirin and dipyridamole and in 216(16%) on aspirin alone (hazard ratio 0.80,95% CI 0.66–0.98; absolute risk reduction 1.0% per year, 95% CI 0.1–1.8). Addition of the ESPRIT data to the meta-analysis of       previous trials resulted in an overall risk ratio for the composite of vascular death, stroke,or myocardial infarction of 0.82 (95% CI 0.74–0.91). Patients on aspirin and dipyridamole discontinued trial medication more often than those on    aspirin alone (470 vs 184), mainly because of headache.

    The ESPRIT results, combined with the results of previous trials, provide suffi cient evidence to prefer the         combination regimen of aspirin plus dipyridamole over aspirin alone as antithrombotic therapy after cerebral
ischaemia of arterial origin.