Prevention with low-dose aspirin plus dipyridamole in patients with disabling stroke

Abstract

Background and purpose: The combination of low-dose aspirin and dipyridamole is more effective than aspirin alone in reducing the risk of recurrent stroke and other major cardiovascular events in patients with a recent transient ischemic attack or minor stroke. It is unknown whether this also applies to patients with a disabling stroke.

Methods: We reanalyzed the data of 5700 patients from ESPRIT and ESPS-2 to study the effect of aspirin and dipyridamole according to modified Rankin scale (mRS) score at baseline. Primary outcome was vascular events (stroke, myocardial infarction, or vascular death). We used proportional hazards regression to estimate the treatment effect across mRS strata at baseline, and we tested for interactions with treatment.

Results: In total, 426 patients (7.5%) had mRS score of 4 or 5 at baseline. The risk of an outcome event increased with mRS score. The relative risk associated with the combination of aspirin and dipyridamole compared to aspirin alone in patients with mRS score 0 to 5 was 0.79 (95% confidence interval, 0.69-0.91). The relative risk according to mRS subcategory score 0 to 4 at baseline varied between 0.73 and 0.96 for vascular events and between 0.62 and 0.96 for stroke. The number of patients with mRS score 5 was too small for reliable estimates, but the data suggest a beneficial effect. There was no evidence of interaction between treatment effect and mRS score at baseline.

Conclusions: The beneficial effect of the combination of low-dose aspirin and dipyridamole was present in all subcategories of the mRS score.