A groundbreaking international study co-led by the Ottawa Heart Institute and the Research Institute of the McGill University Health Centre has revealed that patients who have undergone successful catheter ablation for atrial fibrillation (AF) may no longer require long-term blood thinner therapy. This discovery, poised to transform clinical practice, was presented at the American Heart Association (AHA) Scientific Sessions 2025 in New Orleans and published in the New England Journal of Medicine (NEJM).
The Optimal Anticoagulation for Enhanced Risk Patients Post-Catheter Ablation for Atrial Fibrillation (OCEAN) trial, led by Dr. Atul Verma and Dr. David Birnie, followed 1,284 patients across multiple international sites over three years. The study found no significant difference in stroke or embolic event rates between patients continuing anticoagulation therapy and those taking low-dose aspirin.
Revolutionizing AFib Treatment
For years, patients who underwent AF ablation to restore normal heart rhythm were advised to continue life-long oral anticoagulants, or “blood thinners,” to prevent stroke or embolism. This recommendation persisted due to uncertainty about whether ablation effectively reduced stroke risk. The OCEAN trial provides the first definitive evidence that post-ablation, the risk of stroke is low enough to discontinue blood thinners.
“This is one of the most important clinical questions in modern electrophysiology, and the OCEAN trial gives us the answer we’ve been seeking,” said Dr. Atul Verma, co-principal investigator.
Dr. David Birnie added, “For the majority of the one million people each year who undergo catheter ablation for atrial fibrillation, this study is a game-changer. Our results show that one year after a successful ablation, the risk of stroke is so low that the downsides of continuing blood thinners outweigh the benefits.”
Study Findings and Implications
The randomized study compared patients taking rivaroxaban, a commonly prescribed anticoagulant, with those taking aspirin. After three years, stroke and embolism rates were similarly low in both groups, comparable to individuals who had never experienced AF. However, those on blood thinners faced more clinically significant bleeding events, highlighting the potential harms of unnecessary anticoagulation.
The trial was conducted through a collaborative network of cardiovascular research centres across 56 sites in Canada, Europe, China, and Australia.
Dr. George Wells, director of the Cardiovascular Research Methods Centre at the Ottawa Heart Institute, emphasized the importance of collaboration in achieving the study’s rigorous and impactful results. “Collaboration was essential to ensuring the study’s rigour and impact, and it’s what ultimately allows findings like these to improve patient care on a global scale,” he stated.
Background and Future Directions
The OCEAN trial’s findings are expected to influence clinical guidelines and patient care significantly. Historically, the management of AFib has involved balancing the benefits of stroke prevention with the risks of bleeding associated with anticoagulants. This study suggests a shift towards more personalized treatment plans, potentially reducing medication burdens for many patients.
Supported by organizations such as Bayer, Abbott, Biotronik, and the Canadian Institutes for Health Research, the trial underscores the potential for research-driven changes in medical practice. As healthcare systems worldwide consider these findings, the emphasis will likely be on tailoring treatment to individual patient needs, reducing unnecessary medication use, and focusing on quality of life improvements.
As the medical community digests these findings, further research may explore additional patient subgroups or long-term outcomes. For now, the OCEAN trial stands as a pivotal moment in AFib treatment, offering hope for safer, more effective care.
