People who suffer a brain haemorrhage can take common medicines like aspirin and clopidogrel without raising their risk of another stroke, a major clinical trial has found. Researchers say the findings are reassuring for the thousands of people who take the medicines to reduce their risk of heart attack and another common type of stroke caused by blood clots in the brain.
These everyday treatments – known as antiplatelet medicines – work by slowing or stopping blood from clotting. They are often prescribed to older people because they can lower risk of heart attack and stroke caused by a blood clot.
Doctors had thought the medicines – which include aspirin and clopidogrel – might make people with stroke due to brain haemorrhage more likely to suffer another bleed in the brain.
Researchers led by the University of Edinburgh tracked outcomes from 537 people from across the UK who had suffered a brain haemorrhage while they were taking medicines to stop blood clotting. Patients were randomly assigned to either start taking antiplatelet treatment or avoid it for up to five years.
The team found that people who took antiplatelet medicines experienced fewer recurrences of brain haemorrhage compared with those who did not take these treatments. Some 12 people suffered a brain bleed while taking the medication compared with 23 people who did not. This may suggest the treatments reduce rather than increase risk of further bleeding in the brain, the researchers say, but further studies are needed to confirm this.
Around half of the participants underwent an additional brain scan using MRI at the beginning of the study.
These scans are often used by doctors to check for the presence of tiny blood deposits in the brain, known as microbleeds, which can be a warning sign of future strokes. The researchers found treatment with antiplatelet medication was not more hazardous for people who already had microbleeds in their brain.
Experts say this provides further reassurance that brain haemorrhage survivors can safely continue to take antiplatelet medicines to reduce their risk of future heart attacks or strokes. It also suggests that patients do not need to undergo an MRI scan before starting treatment. This is important because older people are often unable to have an MRI.
The study – called RESTART – was funded by the British Heart Foundation. Findings are being presented at the European Stroke Organisation Conference in Milan.
Background: Antiplatelet therapy reduces the risk of major vascular events for people with occlusive vascular disease, although it might increase the risk of intracranial haemorrhage. Patients surviving the commonest subtype of intracranial haemorrhage, intracerebral haemorrhage, are at risk of both haemorrhagic and occlusive vascular events, but whether antiplatelet therapy can be used safely is unclear. We aimed to estimate the relative and absolute effects of antiplatelet therapy on recurrent intracerebral haemorrhage and whether this risk might exceed any reduction of occlusive vascular events.
Methods: The REstart or STop Antithrombotics Randomised Trial (RESTART) was a prospective, randomised, open-label, blinded endpoint, parallel-group trial at 122 hospitals in the UK. We recruited adults (≥18 years) who were taking antithrombotic (antiplatelet or anticoagulant) therapy for the prevention of occlusive vascular disease when they developed intracerebral haemorrhage, discontinued antithrombotic therapy, and survived for 24 h. Computerised randomisation incorporating minimisation allocated participants (1:1) to start or avoid antiplatelet therapy. We followed participants for the primary outcome (recurrent symptomatic intracerebral haemorrhage) for up to 5 years. We analysed data from all randomised participants using Cox proportional hazards regression, adjusted for minimisation covariates. This trial is registered with ISRCTN (number ISRCTN71907627).
Findings: Between May 22, 2013, and May 31, 2018, 537 participants were recruited a median of 76 days (IQR 29–146) after intracerebral haemorrhage onset: 268 were assigned to start and 269 (one withdrew) to avoid antiplatelet therapy. Participants were followed for a median of 2·0 years (IQR [1·0– 3·0]; completeness 99·3%). 12 (4%) of 268 participants allocated to antiplatelet therapy had recurrence of intracerebral haemorrhage compared with 23 (9%) of 268 participants allocated to avoid antiplatelet therapy (adjusted hazard ratio 0·51 [95% CI 0·25–1·03]; p=0·060). 18 (7%) participants allocated to antiplatelet therapy experienced major haemorrhagic events compared with 25 (9%) participants allocated to avoid antiplatelet therapy (0·71 [0·39–1·30]; p=0·27), and 39 [15%] participants allocated to antiplatelet therapy had major occlusive vascular events compared with 38 [14%] allocated to avoid antiplatelet therapy (1·02 [0·65–1·60]; p=0·92).
Interpretation: These results exclude all but a very modest increase in the risk of recurrent intracerebral haemorrhage with antiplatelet therapy for patients on antithrombotic therapy for the prevention of occlusive vascular disease when they developed intracerebral haemorrhage. The risk of recurrent intracerebral haemorrhage is probably too small to exceed the established benefits of antiplatelet therapy for secondary prevention.