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

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 they underwent catheter ablation to treat AFib, revealing that prescribing the blood thinner rivaroxaban offered no significant advantage in stroke protection compared to aspirin while increasing bleeding risk substantially.

The study evaluated whether long-term oral anticoagulation is needed after successful ablation in people with increased stroke risk. Participants included individuals with no evidence of irregular heart rhythm recurrence and those with moderate to high stroke risk who would typically require long-term blood thinners. Atrial fibrillation increases stroke risk by five-fold and can lead to blood clots, heart failure and death, affecting an estimated five million people in the U.S. with projections exceeding 12 million by 2030 according to the American Heart Association's 2025 Heart Disease and Stroke Statistics report available at https://www.heart.org.

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. Study author Atul Verma, M.D., director of cardiology at McGill University Health Centre in Montreal, explained the significance of these findings: "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. 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."

Researchers prescribed half of the eligible participants 75-160 mg of aspirin daily while the other half received 15 mg daily of oral rivaroxaban. The results showed the three-year risk of stroke, including covert strokes detectable only on 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, with variances not significant enough to indicate notable differences between groups. While there were no notable differences in major or fatal bleeding complications, clinically relevant non-major bleeding was 5.5% for rivaroxaban versus 1.6% for aspirin, making bleeding events about 3.5 times more likely with rivaroxaban.

The study enrolled 1,284 adults with an average age of 66 years, 71% men, who were within 16.4 months of their last ablation procedure on average. Participants were enrolled in healthcare centers in Canada, Australia, Germany, Belgium, Israel and China between March 30, 2016, and July 25, 2022. Researchers used the CHA2DS2-VASc score to measure stroke risk, with the average score at enrollment being 2.2 and nearly 32% of participants having a score of 3 or higher, considered high risk. All participants had brain magnetic resonance imaging at enrollment and again at three years to detect covert strokes.

Verma concluded: "In essence, catheter ablation for AFib reduced the recurrence of atrial fibrillation and can also reduce the risk of stroke associated with this common heart rhythm condition. With the notably increased bleeding risk associated with rivaroxaban, we concluded that the anticoagulant did not offer any advantages in comparison to aspirin for reducing what we found to be a low stroke risk in these individuals. Now, we can advise patients that it may be safe to stop blood thinners, even if they have a moderate stroke risk." The findings are considered preliminary until published as a full manuscript in the peer-reviewed scientific journal New England Journal of Medicine at https://www.nejm.org.