Effects of alteplase on survival after ischaemic stroke (IST-3): 3 year follow-up of a randomised, controlled, open-label trial

Background The effect of alteplase on patient survival after ischaemic stroke is the subject of debate. We report the effect of intravenous alteplase on long-term survival after ischaemic stroke of participants in the Third International Stroke Trial (IST-3). Methods In IST-3, done at 156 hospitals in 12 countries (Australia, Europe, and the UK), participants (aged >18 years) were randomly assigned with a telephone voice-activated or web-based system in a 1: 1 ratio to treatment with intravenous 0.9 mg/kg alteplase plus standard care or standard care alone within 6 h of ischaemic stroke. We followed up participants in the UK and Scandinavia (Sweden and Norway) for survival up to 3 years after randomisation using data from national registries and compared survival in the two groups with proportional hazards survival analysis, adjusting for key prognostic variables. IST-3 is registered with the ISRCTN registry, number ISRCTN25765518. Findings Between May 5, 2000, and July 27, 2011, 3035 participants were enrolled in IST-3. Of these, 1948 (64%) of 3035 participants were scheduled for analysis of 3 year survival, and 1946 (>99%) of these were included in the analysis (967 [50%] in the alteplase plus standard care group and 979 [50%] in the standard care alone group). By 3 years after randomisation, 453 (47%) of 967 participants in the alteplase plus standard care group and 494 (50%) of 979 in the standard care alone group had died (risk difference 3.6% [95% CI -0.8 to 8.1]). Participants allocated to alteplase had a significantly higher hazard of death during the first 7 days (99 [10%] of 967 died in the alteplase plus standard care group vs 65 [7%] of 979 in the standard care alone group; hazard ratio 1.52 [95% CI 1.11-2.08]; p=0.004) and a significantly lower hazard of death between 8 days and 3 years (354 [41%] of 868 vs 429 [47%] of 914; 0.78 [0.68-0.90]; p=0.007). Interpretation Alteplase treatment within 6 h after ischaemic stroke was associated with a small, non-significant reduction in risk of death at 3 years, but among individuals who survived the acute phase, treatment was associated with a significant increase in long-term survival. These results are reassuring for clinicians who have expressed concerns about the effect of alteplase on survival.