Prompt thrombolytic therapy with intravenous alteplase reduces disability after acute ischemic stroke. In an exploratory analysis we examined whether long-term survival varied by baseline characteristics after alteplase.

In this open-treatment, international, randomized, controlled trial, ischemic stroke patients were randomly allocated <6h of onset to intravenous alteplase (0·9 mg/kg) plus standard care (n=1515) or standard care alone (n=1520). We followed patients to death, censoring when last known to be alive. We grouped patients by delay to randomization, and ‘good’ or ‘poor’ predicted prognosis (calculated from baseline NIHS score and age). We present absolute mortality differences between treated and control groups at 7 days, 6 months and 18 months post stroke.

Alteplase was not associated with a significant increase in mortality within 18 months [0.6% (95%CI:−2.9% to +4.2) P=0.72] in all patients with complete vital status (99.9%, 3034/3035). In patients randomized <3 hrs of stroke, 18 month mortality was lower in the alteplase treated group than the control group [40.6%(95%CI:42.6–52.7) vs 47.8%(95%CI:35.5–45.3)P=0.0434].The difference in 18 month mortality between alteplase-treated and control patients was greater in patients who were randomized early (<3h) compared to late (3-6h) [+9%(95%CI:1–17)P=0.0317]. Alteplase led to a greater improvement in 18 month survival in patients with a poor prognosis than in patients with a good prognosis [+8% (95%CI: 2–14)P=0.0091].

These exploratory analyses of the IST-3 trial support improving acute stroke patients’ access to earlier alteplase treatment; treatment of patients with poor prognosis; and further randomized controlled trials in minor stroke to replicate these findings.

www.controlled-trials.com. Unique identifier: ISRCTN25765518