A related editorial discusses this research. These numerically similar outcomes between the 2 groups are quite a departure from a 10% difference observed in a meta-analysis and the 9% difference postulated by the investigators. The trial design however created a situation that made it very difficult to show treatment benefit. The eligibility criterion of “not clearly disabling” meant that at enrollment, all patients met the criterion for success. To show a benefit, alteplase treatment would have to prevent patients from worsening, not improve recovery.
The findings from this study provide more certain, but not definitive, evidence suggesting that intravenous alteplase appears unlikely to meaningfully improve functional outcome in patients with mild ischaemic stroke with initial National Institutes of Health Stroke Scale scores of 5 or lower and with nondisabling deficits, and that for these patients, treatment with aspirin along with close monitoring may be an appropriate course of action.