Pivotal randomised trials of aspirin versus aspirin plus dipyridamole

	Second European stroke prevention study (ESPS-2)	European/Australian stroke prevention in reversible ischaemia trial (ESPRIT)
Primary publication	1996	2006
Type of trial	Randomised, placebo controlled	Randomised, open control
Participants	Adult patients within 3 months of an ischaemic stroke or transient ischaemic attack	Adult patients 0-6 months after minor ischaemic stroke or transient ischaemic attack of presumed arterial origin (patients with a cardioembolic source such as atrial fibrillation excluded)
Mean age (years)	67	63
Sex (percentage male)	58	65
Randomisation	3299 patients randomised between relevant treatment arms: aspirin 25 mg twice daily; aspirin 25 mg twice daily plus modified release dipyridamole 200 mg twice daily	2739 patients randomised between relevant treatment arms: aspirin 30-325 mg (median 75 mg) daily; aspirin 30-325 mg daily plus dipyridamole 200 mg twice daily (85% used modified release preparation)
Follow-up (years)	2	3.5
Average annual risk of vascular events in aspirin only treatment arm (%)	10	5
Outcome of aspirin plus dipyridamole v aspirin alone	Significantly reduced vascular events (relative risk 0.78, 95% confidence interval 0.67 to 0.91)— as a result of significant reduction in stroke, with no detectable effect on either myocardial infarction or vascular death (although numbers of non-stroke outcomes were small)	Significantly reduced vascular events (0.78, 95% confidence interval 0.64 to 0.96)—as a result of reductions in each of ischaemic stroke, cardiac events, and vascular death, although none of these was independently significant. Benefits continued to accrue during follow-up for up to five years. No significant differences were seen in the relative effects of treatment according to several characteristics, including age, sex , history of ischaemic heart disease, and aspirin dose