A drug that breaks up blood clots in stroke patients’ brains could be used more widely without increased risk, a study shows.
It had been thought that giving the drug to people with signs of early brain damage caused by a stroke would increase the chances of them suffering a bleed - which can be fatal.
The study is the first to show that early tissue damage seen in brain scans does not necessarily indicate an increased risk of bleeding.
Patients with early tissue damage from strokes are less likely to make a full recovery, but still benefit from receiving the drug.
The drug - called alteplase - is the only treatment for stroke caused by a blocked blood vessel in the brain.
Worries over the appearance of brain scans have probably meant patients who could have benefitted from alteplase did not receive it.
Experts were concerned that patients with early brain tissue damage - which can be difficult for doctors to see - were more likely to suffer a bleed if they were treated with alteplase.
Researchers found there is only an increased risk of bleeds in patients with multiple signs of tissue damage caused by other diseases and signs of a fresh blood clot.
In the small number of people with old tissue damage and a new blood clot, 14 per cent of those given alteplase are likely to have a haemorrhage.
In people without these signs, three per cent are expected to suffer a bleed if they are given the drug.
Bleeding in the brain is the main side effect of alteplase, so if we can avoid that hazard, then patients are more likely to benefit.
Researchers analysed more than 3,000 people involved in a clinical trial assessing the effectiveness of alteplase as a stroke treatment.
Patient risk factors are easy to identify in brain scans, enabling doctors to decide whether the risk to patients outweighs the potential benefits of receiving alteplase.
The study, published in the journal The Lancet Neurology, was funded by the Medical Research Council.