New research coordinated by the Ottawa Heart Institute is being called a game-changer for people with atrial fibrillation – the most common cause of irregular heartbeats.
Currently, patients who undergo successful treatment for atrial fibrillation are routinely told to remain on blood thinners for life to reduce the risk of stroke. That will now change for patients around the world, said Dr. David Birnie, who heads the Division of Cardiology at the Ottawa Heart Institute and is a professor in the Department of Medicine at the University of Ottawa. He co-led the international study.
The research, published in the New England Journal of Medicine, found that remaining on blood thinners after successful treatment is not necessary because the risk of stroke after ablation treatment is so low it is as if they never had atrial fibrillation.
The study, which began in 2013, has been highly anticipated, Birnie said. It will be translated into clinical practice, meaning continuing use of blood thinners will no longer be recommended in clinical guidelines for treating patients after successful treatments for atrial fibrillation. But change will likely come more quickly than that, he said.
“Doctors will be contacting their patients almost immediately to tell them they can stop blood thinners,” he said. That is the advice he will give to his patients.
Atrial fibrillation, the most common form of cardiac arrhythmia, affects one per cent of Canadians, but the rate increases to five per cent at the age of 65. It is caused by a problem with the heart’s electrical system, often related to other health issues.
Cardiac ablation for atrial fibrillation is a common, minimally invasive procedure done through a blood vessel to the heart in which small scars are created to stop the heart’s electrical system dysfunction. It is successful in about 80 per cent of cases, said Birnie. It is done as a day procedure at the Ottawa Heart Institute.
Some one million people a year undergo cardiac ablation treatment for atrial fibrillation.
The randomized study included more than 1,200 patients around the world who had undergone a successful ablation for atrial fibrillation. Patients in one arm of the trial took a commonly prescribed blood thinner, and those in the other arm were prescribed low doses of aspirin. They were followed for three years.
Researchers found that treatment with the blood thinners did not lead to a significantly lower incidence of stroke than treatment with aspirin. Ninety-six per cent of patients in both groups had no evidence of a new ischemic stroke three years later.
Atrial fibrillation increases the risk of stroke because it can cause blood to pool long enough for clots to form that can then cause strokes.
Although successful ablation treatments reset the heart’s rhythms to normal, clinicians have always been reluctant to stop blood thinners after an earlier study showed the risk of stroke remained high in patients even after treatment with medication that returned the heart’s rhythm to normal.
The newly published research co-led by Birnie looked at whether that practice continued to be necessary after successful ablation procedures.
“We have always been nervous about stopping blood thinners,” said Birnie. “This is a breakthrough.”
Remaining on blood thinners can be difficult for patients. Not only are they expensive, but they can increase a patient’s risk of severe bleeding – serious enough to be fatal at times.
“They can significantly decrease a patient’s quality of life,” he said. Patients taking them have to be extremely careful of falls that could cause bleeding.
Dr. Atul Verma, director of the Division of Cardiology at the McGill University Health Centre, and co-lead of the study, said it is “incredibly rewarding to see years of careful research translate directly into safer, simpler care for patients.”
Birnie said the research should be a point of pride for Canadians.
“It is a tremendous thing for Canada to be proud of. The U.S. can’t do trials like this.” He noted the research was not industry funded but mainly funded through the CIHR (Canadian Institutes of Health Research) and involved collaboration among academic centres.
“We in Canada excel in leading these studies.”
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