Further support for later treatment of stroke

[PRESS RELEASE, 25 September 2008] A team of scientists at Karolinska Institutet recently showed that the time window for the treatment of acute ischaemic stroke (i.e. stroke caused by a blood clot) can be lengthened without putting the patient at risk. New results published in the prestigious New England Journal of Medicine show that later treatment is also efficacious in that it improves the patients prospects of recovery.

Thrombolytic treatment with the clot-busting drug alteplase is the only available method of treating acute stroke caused by a blood clot in the brain. However, the treatment is only approved within three hours after onset of stroke, which means that relatively few patients manage to be in a position to receive treatment before this time threshold has been crossed.

Scientists at Karolinska Institutet and the international network SITS (Safe Implementation of Treatments in Stroke) recently presented novel findings that may question present recommendations. The study, which was published in the Lancet on 15 September, demonstrated that thrombolysis administered within three to four and a half hours after a stroke was just as safe as that given within the three-hour time window.

These results are now corroborated by a study published in the top-ranking journal New England Journal of Medicine and co-authored by scientists from Karolinska Institutet. The study in question was a randomised comparative analysis of thrombolysis administered in the 3 to 4.5-hour interval and a placebo control, and shows that thrombolysis is more effective than control treatment and that many patients had recovered after three months.

"Both studies support the idea that the time window for thrombolysis should be extended, and this from the perspective of both safety and efficacy," says Professor Nils Wahlgren, who co-led both studies.

In this present study, 52.4 per cent of the patients who received thrombolysis recovered within three months, compared to 45.2 per cent of the placebo group - a statistically significant difference. A total of 418 patients received thrombolysis and 403 a placebo. The proportion of symptomatic haemorrhages was higher in the experimental group than in the control group, but no higher than in the currently approved 0 to 3-hour interval.

The results of the two studies are to be discussed at Karolinska Stroke Update, an international expert conference to be held from 16 to 18 November in Stockholm, at which a decision is due to be taken on whether the European guidelines should be changed.

Publication:

• Press release about the Lancet study

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