Dr. Ezekowitz presented the results from the large, international, multicentre Apixaban for Reduction In Stroke and Other ThromboemboLic Events (ARISTOTLE) in atrial fibrillation trial. It is the largest prospective trial yet reported for stroke prevention in atrial fibrillation. The trial randomized 18,201 patients with at least one additional risk factor for stroke, such as age greater than 75 years, prior stroke or transient ischemic attack, systemic embolism, heart failure or left ventricular ejection fraction less than 40 per cent, diabetes, or high blood pressure.
The patients came from over 1,000 sites in 39 countries. Their mean age was 70 years and 31 per cent were 75 or older. There were 19 per cent with prior stroke, 87 per cent had high blood pressure, 28 per cent had heart failure or reduced left ventricular ejection fraction, and 24 per cent had diabetesmellitus. Canada supplied a very large cohort of 1,057 patients, said Dr. Ezekowitz, who led the Canadian arm of the trial with Dr. Paul Dorian from the University of Toronto.
The patients were randomized to apixaban 5 mg twice daily versus dose-adjusted warfarin which is often used to treat AF − using a double-blind, double-dummy design. Warfarin or warfarin placebo was monitored adjusted to a target INR of two to three using a blinded, encrypted point-of-care device. "This was the best possible clinical trial design," says Dr. Ezekowitz.
A bit more than half of the patients (57 per cent) had used warfarin before entering the study, and 43 per cent were new to warfarin. The patients were followed for 1.8 years, on average.
The study found that apixaban is effective at treating AF. It was also better at reducing all-cause mortality and was associated with less bleeding.
pecifically, apixaban reduced the chance of stroke and systemic embolism by 21 per cent, reduced major bleeding by 31 per cent, and reduced
|Contact: Amanda Bates|
Heart and Stroke Foundation of Canada