Successful catheter ablation for atrial fibrillation significantly reduces stroke risk and may eliminate the need for ongoing blood-thinning medication in many patients, according to new research presented at the American Heart Association's Scientific Sessions 2025. The international OCEAN Randomized Trial followed nearly 1,300 adults for three years after they underwent catheter ablation to treat AFib, a condition that increases stroke risk five-fold and affects an estimated five million people in the U.S.
The study compared outcomes between patients taking the blood thinner rivaroxaban and those taking aspirin. Researchers found that prescribing rivaroxaban after catheter ablation offered no significant advantage in stroke protection compared to aspirin, while increasing bleeding risk substantially. 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.
However, clinically relevant non-major bleeding events were 3.5 times more likely with rivaroxaban, occurring in 5.5% of patients compared to 1.6% in the aspirin group. There were no notable differences in major or fatal bleeding complications between the two medications. The findings suggest that successful catheter ablation reduces AFib recurrence and the associated stroke risk to such low levels that potent anticoagulants may no longer provide additional benefit for many patients.
Current American Heart Association guidelines recommend continuing blood-thinning medications in moderate-to-high risk individuals even after successful ablation. Study author Atul Verma, M.D., director of cardiology at McGill University Health Centre in Montreal, noted that until now, physicians have advised patients to continue blood thinners due to insufficient evidence about safety. The study's findings, simultaneously published in the New England Journal of Medicine, provide the evidence needed to reconsider this approach.
The research enrolled participants from healthcare centers in Canada, Australia, Germany, Belgium, Israel and China between 2016 and 2022. Participants had an average age of 66 years, were 71% male, and were within approximately 16 months of their last ablation procedure. Researchers used the CHA2DS2-VASc score to measure stroke risk, with participants averaging a score of 2.2 and nearly 32% having scores of 3 or higher, considered high risk.
While the findings are promising, researchers note limitations including that only a small percentage of participants had very high CHA2DS2-VASc scores of 4 or higher, meaning the results may not apply to the highest-risk individuals. The study represents a significant shift in managing AFib patients post-ablation, potentially reducing medication burden and bleeding risks while maintaining stroke protection for millions of people worldwide.
