Successful catheter ablation for atrial fibrillation resulted in a low risk of stroke associated with the irregular heart rhythm condition, according to findings from the OCEAN Randomized Trial presented at the American Heart Association's Scientific Sessions 2025. The international study followed nearly 1,300 adults for three years after their ablation procedures and found that prescribing the blood thinner rivaroxaban offered no significant stroke protection advantage over aspirin while increasing bleeding risk substantially.
The study's implications are significant for the estimated five million Americans living with atrial fibrillation, a condition that increases stroke risk five-fold and can lead to blood clots, heart failure and death. Current American Heart Association/American College of Cardiology guidelines recommend continuing blood-thinning medications in moderate-to-high risk individuals to prevent stroke, even after successful ablation. This research challenges that standard practice by demonstrating that successful ablation may reduce stroke risk enough to make potent anticoagulants unnecessary for many patients.
Researchers found 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% in the rivaroxaban arm and 0.7% in the aspirin arm, variances not significant enough to indicate notable differences between groups. However, clinically relevant non-major bleeding was 5.5% for rivaroxaban versus 1.6% for aspirin, making bleeding complications about 3.5 times more likely with the stronger blood thinner.
Study author Atul Verma, M.D., director of cardiology at McGill University Health Centre in Montreal, explained the clinical significance of these findings. Many patients who undergo successful ablation ask whether they can stop their blood thinners, but until now, physicians have advised continued use due to insufficient evidence about safety. The study provides that evidence, suggesting catheter ablation not only reduces AFib recurrence but also lowers stroke risk associated with the condition.
The research was simultaneously published as a full manuscript in the peer-reviewed scientific journal New England Journal of Medicine. Participants were enrolled in healthcare centers across 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 averaging a score of 2.2, and nearly 32% having scores of 3 or higher, considered high risk.
This development matters because atrial fibrillation prevalence is projected to affect more than 12 million Americans by 2030 according to the American Heart Association's 2025 Heart Disease and Stroke Statistics report available at https://www.heart.org. The ability to safely discontinue potent blood thinners after successful ablation could significantly improve quality of life for millions by reducing bleeding risks and medication costs while maintaining stroke protection. Additional information about atrial fibrillation is available through the American Heart Association's health initiative at https://www.heart.org/en/health-topics/atrial-fibrillation.
