A minimally invasive heart procedure called catheter ablation may reduce the risk of stroke in patients with atrial fibrillation (AFib) enough that some can safely stop taking blood thinners, according to research presented at the American Heart Association’s Scientific Sessions 2025.
The OCEAN Randomized Trial, simultaneously published in the New England Journal of Medicine, evaluated whether long-term oral anticoagulation is needed after successful ablation in people with an increased risk of stroke. Researchers enrolled nearly 1,300 adults at multiple sites across Canada, Australia, Germany, Belgium, Israel and China, following them for three years after ablation.
Participants had no evidence of irregular heart rhythm recurrence and had moderate to high stroke risk, which typically calls for long-term blood thinners. Half were prescribed 75-160 mg of aspirin daily, while the other half received 15 mg of rivaroxaban, a potent blood thinner. The study found that rivaroxaban offered no major difference in stroke protection compared to aspirin but increased bleeding risk.
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. Annual stroke risk was 0.3% with rivaroxaban versus 0.7% with aspirin, differences not statistically significant. Clinically relevant non-major bleeding occurred in 5.5% of rivaroxaban users compared to 1.6% of aspirin users—about 3.5 times higher.
“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,” said study author Dr. Atul Verma, director of cardiology at McGill University Health Centre. “Now, we can advise patients that it may be safe to stop blood thinners, even if they have a moderate stroke risk.”
AFib increases stroke risk five-fold and affects an estimated 5 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. Current American Heart Association/American College of Cardiology guidelines recommend continuing blood thinners in moderate-to-high risk individuals even after successful ablation, but this study challenges that practice.
Among the study’s limitations, only a small percentage of participants had a CHA2DS2-VASc score of 4 or higher, meaning findings may not apply to very high-risk individuals. The average score was 2.2, and nearly 32% had a score of 3 or higher.
The results suggest that for many AFib patients who undergo successful ablation, the risk of stroke becomes low enough that potent anticoagulants like rivaroxaban offer no benefit over aspirin and carry higher bleeding risk. This could change clinical practice, allowing patients to discontinue blood thinners after ablation.
