Background: In the European Cooperative Acute Stroke Study III (ECASS III), alteplase administered 3.0-4.5 h after the onset of stroke symptoms resulted in a significant benefit in the primary endpoint (modified Rankin scale [mRS] score 0-1) versus placebo, with no difference in mortality between the treatment groups. Compared with the 0-3 h window, there was no excess risk of symptomatic intracranial haemorrhage. We assessed the usefulness of additional endpoints and did subgroup and sensitivity analyses to further investigate the benefit of alteplase.
Methods: In a double-blind, multicentre study in Europe, patients with acute ischaemic stroke were randomly assigned to intravenous alteplase (0.9 mg/kg bodyweight) or placebo. Additional outcome analyses included functional endpoints at day 90 or day 30 (mRS 0-1 [day 30], mRS 0-2, Barthel index > or =85, and global outcome statistic [day 30]) and treatment response (8-point improvement from baseline or 0-1 score on the National Institutes of Health stroke scale [NIHSS], and a stratified responder analysis by baseline NIHSS score). The subgroup analyses were based on the mRS 0-1 at day 90, symptomatic intracranial haemorrhage, and death. Analyses were by intention to treat and per protocol. This study is registered with ClinicalTrials.gov, number NCT00153036.
Findings: 418 patients were assigned to alteplase and 403 to placebo. Although not significant in every case, all additional endpoints showed at least a clear trend in favour of alteplase. Alteplase was effective in various subgroups, including older patients (<65 years: odds ratio 1.61, 95% CI 1.05-2.48; > or =65 years: 1.15, 0.80-1.64; p=0.230), and the effectiveness was independent of the severity of stroke at baseline (NIHSS 0-9: 1.28, 0.84-1.96; NIHSS 10-19: 1.16, 0.73-1.84; NIHSS > or =20: 2.32, 0.61-8.90; p=0.631). The incidence of symptomatic intracranial haemorrhage seemed to be independent of previous antiplatelet drug use (no: 2.41, 1.09-5.33; yes: 2.33, 0.79-6.90; p=0.962) and time from onset of symptoms to treatment (181-210 min: 1.62, 0.26-10.25; 211-240 min: 1.97, 0.82-4.76; 241-270 min: 3.15, 1.01-9.79; p=0.761), but not of age dichotomised at 65 years (<65 years: 0.74, 0.28-1.96; > or =65 years: 5.79, 2.18-15.39; p=0.004).
Interpretation: Our results support the use of alteplase up to 4.5 h after the onset of stroke symptoms across a broad range of subgroups of patients who meet the requirements of the European product label but miss the approved treatment window of 0-3 h.
Funding: Boehringer Ingelheim.