New analyses of data from ECASS 3 (Third European Cooperative Acute Stroke Study) suggest that the thrombolytic, tPA (alteplase) has benefits in the treatment of stroke up to 4.5 hours after symptom onset. This builds on the current approved time window of three hours.
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This new report from ECASS 3 was published online on October 21st in Lancet Neurology. The authors, led by Dr Werner Hacke (Ruprecht-Karls-Universität, Germany) report that although not all end points were statistically significant, there was “a clear pattern in favour of alteplase”.
In the ECASS 3 trial, 821 stroke patients presenting 3-4.5 hours after symptom onset were randomised to alteplase (in the approved regimen of 0.9 mg/kg body weight) or placebo.
The primary end point was disability at 90 days, and this was judged by a favourable or unfavourable outcome on the modified Rankin Scale. Results showed that significantly more patients treated with tPA had a favourable outcome (52.4%) by this measure than those who received placebo (45.2%), giving an odds ratio of 1.34 (p=0.04).
A secondary end point, a combination of four neurologic and disability scores, also showed an improvement with the thrombolytic therapy (odds ratio 1.28; p<0.05). These beneficial effects of alteplase were evident regardless of patient age and the severity of stroke.
There was an increase in intracerebral haemorrhage with alteplase but this was not associated with an increase in mortality. The incidence of symptomatic intracranial haemorrhage appeared to be independent of previous antiplatelet drug use, and time from onset of symptoms to treatment, but was influenced by age, with a much higher incidence in patients aged over 65 years (odds ratio versus placebo 5.79) than those under 65 years (odds ratio versus placebo 0.74).
“Even with these encouraging findings, the most important principle of acute stroke intervention should, however, not be lost—i.e. time remains critical, and fast treatment still provides the greatest chance of recovery,” the authors conclude.