More stroke survivors can be given blood thinning medication

Prescribing blood thinners for stroke survivors is safer than previously thought, according to new research that could change current clinical practice.

The UCLH and UCL researchers said the findings – published in the Lancet Neurology – should mean some stroke patients are no longer denied the best treatment for them.

Most strokes (about 80%) are ischaemic strokes which are caused by a blocked artery. To reduce the risk of another ischaemic stroke doctors usually give patients blood thinning medications like aspirin or anticoagulants. However, these drugs are associated with an increased risk of a rare but often lethal or disabling side effect of serious bleeding in the brain (a brain haemorrhage).

Prior to this study it was thought that patients found to have tiny pinpoint bleeds in the brain, known as cerebral microbleeds, before being giving blood thinners may be at higher risk of brain haemorrhage compared with their risk of a repeat ischaemic stroke, meaning that blood thinners should be avoided in these patients. This uncertainty frequently causes anxiety for doctors and patients. 

But an analysis of international data – including from the BRC-supported Stroke Investigation in North and central London (SIGNaL) project – found that microbleeds predicted not only brain haemorrhage as previously thought, but also ischaemic stroke, and that regardless of the number of microbleeds present, the risk of a repeat ischaemic stroke was always higher than the risk of brain haemorrhage.

“This changes how we think about microbleeds,” said lead author Prof David Werring. “Although the risk of brain haemorrhage does increase with the number of microbleeds, the risk of ischaemic stroke is consistently much higher; interestingly, our results are consistent with emerging evidence that some microbleeds may not be linked to brain bleeding at all.”

“Our findings mean doctors can be more confident in prescribing blood thinning medications to stroke survivors with microbleeds, knowing that these patients will not be at greater risk of brain haemorrhage than ischaemic stroke, and should help to avoid patients being denied effective blood thinning treatments which would help them.”

Read the full paper.