Objectives: In acute stroke, progression has a severe impact on patient outcome and no effective treatment is known. The main objective was to evaluate the efficacy of aspirin for prevention of stroke progression thereby improving outcome.
Design: The trial was randomized, double-blind and placebo-controlled.
Setting: The patients were treated in stroke units of four hospitals in Sweden.
Subjects: Patients with ischaemic stroke but not complete paresis were included. No antiplatelet drugs were allowed within the last 72 h before onset. Delay until first trial dosage was maximized to 48 h. The trial was designed to detect a 20% reduction of the rate of stroke progression, which was estimated to take place in 20% of cases. Totally, 441 patients (220 aspirin, 221 placebo) completed the trial. Baseline comparisons between the groups showed no differences.
Interventions: Aspirin (325 mg) or placebo was given once daily for five consecutive days.
Main outcome measures: Neurological assessments were carried out three times daily during the treatment period to detect progression of at least two points in the Scandinavian Stroke Supervision Scale. Patient outcome was followed up at discharge and at 3 months.
Results: Aspirin treatment did not significantly reduce the frequency of stroke progression. Amongst aspirin-treated patients, stroke progression occurred in 15.9% as compared with 16.7% in the placebo group, which is less frequent than expected. The relative risk was 0.95 (95% CI 0.62-1.45) in the treatment group. As regards patient outcome at discharge and after 3 months, aspirin treatment did not show any difference.
Conclusion: No positive effect of aspirin, of the expected size, could be shown on the frequency of stroke progression or patient outcome.