Mini-stroke should immediately be treated with aspirin, recommend researchers

By Sally Robertson, B.Sc.May 19 2016

Taking aspirin immediately after experiencing stroke-like symptoms could significantly reduce the risk of a major stroke occurring in the next few days, according to a study published in The Lancet.

“This finding has implications for doctors, who should give aspirin immediately if a TIA or minor stroke is suspected, rather than waiting for specialist assessment and investigations,” says lead author of the paper Peter Rothwell (University of Oxford).

Currently, aspirin is administered to patients who have experienced a stroke or “mini-stroke” (transient ischemic attack, TIA) to reduce the risk of a further stroke after they have undergone hospital assessment and for the longer-term.

This reduces the risk of a subsequent stroke by around 15%. However, a previous study, called the EXPRESS study, had led Rothwell and colleagues to suspect that immediate treatment following a TIA could be much more beneficial.

“The risk of a major stroke is very high immediately after a TIA or a minor stroke (about 1000 times higher than the background rate), but only for a few days,” says Rothwell.

“We showed previously in the 'EXPRESS Study' that urgent medical treatment with a 'cocktail' of different drugs could reduce the one-week risk of stroke from about 10% to about 2%, but we didn't know which component of the 'cocktail' was most important.”

Rothwell and team knew that one of the components was aspirin, but they also knew that trials have shown the long-term effect of aspirin in preventing stroke is only modest. The researchers wondered whether the benefit of taking aspirin as early as possible might be much greater.

“If so, taking aspirin as soon as possible after 'warning symptoms' event could be very worthwhile,” remarks Rothwell.

To investigate further, the researchers looked at data from twelve trials, involving a total of 16,000 people, on the use of aspirin for long-term prevention of further strokes, as well as data from three trials, involving a total of 40,000 people, on the use of aspirin for the treatment of acute stroke.

The study revealed that the benefit of aspirin in reducing subsequent stroke risk was almost all in the first few weeks. Rather than aspirin reducing the longer-term risk by 15%, the early risk of a disabling or fatal stroke was reduced by around 75%.

Rothwell says the findings confirm that aspirin is the most important component and is highly effective as an urgent treatment following TIA and minor stroke. As well as the finding having implications for doctors who should administer it immediately in such cases, it also has implications for public education.

After experiencing a TIA, many patients delay or fail to seek medical attention and 50% of recurrent strokes happen before people have been assessed as a result of their TIA.

“Encouraging people to take aspirin if they think they may have had a TIA or minor stroke - experiencing sudden-onset unfamiliar neurological symptoms - could help to address this situation, particularly if urgent medical help is unavailable,” says Rothwell.

Dale Webb from the Stroke Association says he welcomes the research, which is timely because the stroke community are currently trying to draw up new guidelines on stroke.

“The findings suggest that anyone who has stroke symptoms, which are improving while they are awaiting urgent medical attention can, if they are able, take one dose of 300 mg aspirin,” says Webb.