Patients who receive pharmacological thrombolysis within six hours of a stroke are more likely to make a better recovery than those who don't get the same treatment. This according to the world's largest ever trial of the clot-busting drug rtPA, where researchers from Karolinska Institutet participated.
The international trial, called the IST-3 (Third International Stroke Trial), was led by the University of Edinburgh and presented in The Lancet. It shows that following treatment with rtPA (recombinant tissue plasminogen activator), more stroke survivors were able to look after themselves without the help of others. A patient's chances of making a complete recovery within six months of a stroke were also increased. More than 3000 stroke patients from 12 countries took part in the trial, half of whom were treated with intravenous rtPA and half of whom were not. In Sweden, 18 centres and 297 patients were included.
In total about half of those who took part in the trial were aged over 80, which make the researchers conclude that trombolysis also can be an efficient treatment for elderly stroke patients.
However, the benefits of using rtPA do come at a price. Patients are at risk of death within seven days of treatment because the drug can cause a secondary bleed in the brain. The researchers point out that because of the threat of death and disability, many stroke patients are prepared to take the early risks of being treated with rtPA to avoid being disabled. After a week there were also fewer deaths in the rtPA group, so that after six months the mortality was at the same level in both groups.
"For every 1000 patients given rtPA within three hours of stroke, 80 more will survive and live without help from others than if they had not been given the drug", says Dr Veronica Murray, researcher at Karolinska Institutet and national coordinator of the IST-3 in Sweden. "But without treatment, about one fourth of people who suffer a stroke die, with another third left permanently dependent and disabled."
An ischaemic stroke happens when the brain's blood supply is interrupted by a blood clot. The damage caused can be permanent or fatal. Stroke symptoms include paralysis down one side and speech problems.
The multi-centre trial was funded by the University of Edinburgh, AFA Insurances, Karolinska Institutet, The Stockholm County Council, and the Swedish Heart Lung Fund, amongst others. The findings of the study are published in The Lancet alongside a meta-analysis of all other trials of the drug that have been carried out in the past 20 years.
The benefits and harms of intravenous thrombolysis with recombinant tissue plasminogen activator within 6 h of acute ischaemic stroke (the third international stroke trial [IST-3]): a randomised controlled trial. The Lancet, Early Online Publication, 23 May 2012, doi:10.1016/S0140-6736(12)60768-5