New findings hold promise for those with atrial fibrillation

McMaster researchers have found there is a better way to prevent stroke for people with irregular heartbeats. According to research published in the New England Journal of Medicine Thursday, the new drug apixaban, currently under regulatory review, is better than aspirin in reducing stroke in those with atrial fibrillation, otherwise known as an irregular heart beat.

The investigators report that in high-risk patients who have already had a stroke or warning stroke, apixaban reduces stroke from 8.3 per cent per year on aspirin to 2.5 per cent per year. This means that one stroke would be prevented, each year, for every 20 of these high-risk patients treated with apixaban.

The study also found that apixaban is superior to aspirin in reducing stroke in patients with atrial fibrillation who are unsuitable for the traditional therapy of warfarin. It reduces the risk of stroke by more than 50% and, compared to aspirin, apixaban did not significantly increase the risk of major bleeding.

Approximately one in four people aged 40 or older will develop atrial fibrillation during their lifetime. The biggest threat from the disorder is a greatly increased risk of stroke, which is five times higher than for others. Blood thinners such as warfarin reduce this risk but are very hard to use successfully. About a third of patients are unsuitable for the treatment with warfarin, a vitamin K antagonist, which requires life-long blood monitoring.

According to principal investigator Stuart Connolly, apixaban could vastly improve the quality of life for patients who cannot take warfarin.

"Patients with a stroke who have atrial fibrillation and who cannot take warfarin are at particularly high risk of recurrent stroke," said the professor of medicine at the Population Health Research Institute of McMaster and Hamilton Health Sciences. "It is great to know that we now have a drug that can reduce recurrent strokes substantially in these patients and which most patients will be able to take without the need for monitoring."

The full report published on the journal's website follows preliminary results of the AVERROES study of apixaban presented last year. The report is also being presented Thursday at the American Stroke Association's international conference in Los Angeles, CA.

The international study, which involved more than 5,500 patients in 522 centres in 36 countries, was funded by pharmaceutical companies Bristol-Myers Squibb and Pfizer Inc.

Source: McMaster University