Catheter Ablation May Eliminate Need for Blood Thinners in AFib Patients, Study Finds

A minimally invasive heart procedure called catheter ablation may reduce stroke risk enough that some atrial fibrillation patients can safely discontinue blood thinners, according to new research presented at the American Heart Association's Scientific Sessions 2025. The findings from the OCEAN Randomized Trial suggest that successful ablation procedures could eliminate the need for long-term anticoagulation therapy in many AFib patients.

The international study followed 1,284 adults for three years after they underwent catheter ablation to treat atrial fibrillation, a condition that increases stroke risk five-fold and affects an estimated five million people in the United States. Participants included people with no evidence of irregular heart rhythm recurrence and those with moderate to high stroke risk who would typically require long-term blood thinners according to current American Heart Association guidelines.

Researchers compared outcomes between patients taking the blood thinner rivaroxaban and those taking aspirin, finding no significant difference in stroke protection between the two groups. The three-year risk of stroke, including covert strokes detectable only through brain imaging, was 0.8% in the rivaroxaban group and 1.4% in the aspirin group. The annual stroke risk was 0.3% for rivaroxaban versus 0.7% for aspirin, differences not considered statistically significant.

More importantly, the study revealed that rivaroxaban carried substantially higher bleeding risks. Clinically relevant non-major bleeding occurred in 5.5% of patients taking rivaroxaban compared to only 1.6% of those taking aspirin, making bleeding complications about 3.5 times more likely with the potent blood thinner. There were no notable differences in major or fatal bleeding complications between the two groups.

"We know that ablation for AFib is effective, however, we did not know if elimination of the arrhythmia also reduces the long-term risk of stroke," said study author Atul Verma, M.D., director of cardiology at McGill University Health Centre in Montreal. "Many people who have undergone successful ablation will ask 'Can I stop my blood thinners?' Until now, we have told them to continue taking blood thinners because we had insufficient evidence to suggest it was safe to stop."

The findings, simultaneously published in the New England Journal of Medicine, could transform clinical practice for the growing population of AFib patients. With projections indicating more than 12 million Americans will have atrial fibrillation by 2030 according to the Association's 2025 Heart Disease and Stroke Statistics report, the implications for patient care and medication management are substantial.

Study participants had an average age of 66 years, with 71% being men, and were enrolled from healthcare centers in Canada, Australia, Germany, Belgium, Israel and China between March 2016 and July 2022. Researchers used the CHA2DS2-VASc score to measure stroke risk, with participants having an average score of 2.2 at enrollment, and nearly 32% having a score of 3 or higher, which is considered high risk.

The research represents a significant shift in understanding how catheter ablation affects stroke risk in AFib patients. While the procedure has been known to reduce the occurrence of atrial fibrillation, its impact on the associated stroke risk had remained unclear until this study. The findings suggest that successful ablation not only controls the irregular heart rhythm but also addresses the underlying stroke risk, potentially allowing many patients to transition from potent blood thinners to simpler, safer aspirin therapy.

However, researchers noted limitations, including that only a small percentage of participants had very high CHA2DS2-VASc scores of 4 or higher, meaning the findings may not apply to the highest-risk individuals. The study provides new evidence that could help physicians make more informed decisions about anticoagulation therapy following successful ablation procedures, balancing stroke prevention against bleeding risks for millions of AFib patients worldwide.