Thrombolysing stroke patients works up to 4.5 hours after the brain attack

Professor K. Lees and his team have published recently (The Lancet 2010;375:1695-1703) the results of their pooled analysis of the data from the stroke thrombolysis trails. Early administration of intravenous recombinant tissue plasminogen activator (rt-PA) after ischaemic stroke improves outcome. Previous analysis of combined data from individual patients suggested potential benefit beyond 3 h from stroke onset. The team re-examined the effect of time to treatment with intravenous rt-PA (alteplase) on therapeutic benefit and clinical risk by adding recent trial data to the analysis. The data was added from ECASS III (821 patients) and EPITHET (100 patients) to a pool of common data elements from six other trials of alteplase for acute stroke (2775 patients).
The findings showed that treatment was started within 360 min of stroke onset in 3670 patients randomly allocated to alteplase (n=1850) or to placebo (n=1820). Large parenchymal haemorrhage was seen in 96 (5•2%) of 1850 patients assigned to alteplase and 18 (1•0%) of 1820 controls, with no clear relation to onset of start to treatment.

In his interpretation to the results Professor Lees stated that patients with ischaemic stroke selected by clinical symptoms and CT benefit from intravenous alteplase when treated up to 4•5 h. To increase benefit to a maximum, every effort should be taken to shorten delay in initiation of treatment. Beyond 4•5 h, risk might outweigh benefit.