A new international study suggests that people who undergo a minimally invasive heart procedure to treat an irregular heartbeat, called catheter ablation, may not need to stay on blood thinners for life.
The findings were presented at the American Heart Association’s Scientific Sessions 2025 and published in the New England Journal of Medicine.
The research focused on people with atrial fibrillation, or AFib, a common heart rhythm disorder that raises the risk of stroke by five times.
AFib causes the heart to beat irregularly, which can lead to blood clots, heart failure, and even death. In the United States, more than 5 million adults currently have AFib, and that number is expected to more than double by 2030.
Catheter ablation is a non-surgical treatment that targets and destroys the small areas of heart tissue responsible for triggering AFib. The procedure is often successful in restoring normal rhythm and preventing recurrence.
However, current guidelines from the American Heart Association and American College of Cardiology recommend that people with moderate or high stroke risk continue blood-thinning medications even after successful ablation, to prevent clots that could lead to a stroke.
The OCEAN Randomized Trial set out to test whether that lifelong medication is really necessary. The study enrolled nearly 1,300 adults in several countries, including Canada, Australia, Germany, Belgium, Israel, and China.
Participants, who had undergone successful ablation and had no evidence of recurring irregular heart rhythms, were randomly assigned to take either aspirin—a mild blood thinner—or rivaroxaban, a stronger anticoagulant, for three years. The average participant was 66 years old, and most had a moderate risk of stroke, with a CHA2DS2-VASc score of around 2.2.
After three years of follow-up, the results were surprising. The risk of stroke was extremely low in both groups. Only 0.8% of participants taking rivaroxaban experienced a stroke, compared to 1.4% of those taking aspirin.
This difference was not statistically significant, meaning both treatments were equally effective in preventing strokes. The annual risk of stroke was just 0.3% for the rivaroxaban group and 0.7% for the aspirin group—much lower than expected for people with AFib.
However, the researchers did notice a difference when it came to side effects. People taking rivaroxaban were 3.5 times more likely to experience non-serious but clinically significant bleeding, such as nosebleeds or bruising, compared to those taking aspirin. Serious or fatal bleeding events were rare and occurred at similar rates in both groups.
Dr. Atul Verma, the study’s lead author and director of cardiology at McGill University Health Center in Montreal, explained that these results could change how doctors manage patients after ablation.
“We’ve known that ablation can successfully stop AFib, but we didn’t know whether it also reduces stroke risk,” he said. “Now we can tell our patients that, in many cases, it may be safe to stop long-term blood thinners—even if they have a moderate risk of stroke.”
The study’s findings suggest that after successful ablation, the procedure itself may lower stroke risk by restoring normal heart rhythm.
For many patients, continuing powerful anticoagulants like rivaroxaban might not offer extra protection and could expose them to unnecessary bleeding risks. Instead, low-dose aspirin—or in some cases, no blood thinner at all—may be a safer long-term option.
Still, the researchers cautioned that their results might not apply to everyone. Only a small number of participants had very high stroke risk scores (4 or higher), so more research is needed to determine whether those individuals should continue stronger anticoagulants. The study also followed patients for only three years, so long-term outcomes remain to be seen.
Despite these limitations, the OCEAN trial offers hope that many people treated for AFib could eventually reduce or stop their reliance on lifelong blood thinners. For patients, this could mean fewer side effects, less monitoring, and a better quality of life—without increasing their risk of stroke.
As Dr. Verma summarized, “Ablation not only treats AFib but may also protect patients from the long-term complications that come with it. With careful follow-up and individualized care, we may be able to simplify treatment safely for thousands of people around the world.”
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The study is published in New England Journal of Medicine.
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