A groundbreaking trial co-led by the **Ottawa Heart Institute** and the **Research Institute of the McGill University Health Centre** has determined that patients who have undergone successful catheter ablation for atrial fibrillation (AF) may not need to continue long-term blood thinner therapy. This research, known as the **Optimal Anticoagulation for Enhanced Risk Patients Post-Catheter Ablation for Atrial Fibrillation (OCEAN)** trial, suggests that many individuals can safely discontinue anticoagulants without increasing their risk of stroke or embolic events.
The OCEAN trial, which enrolled **1,284 patients** across multiple international sites over a three-year period, provides the first conclusive evidence that after a successful ablation, the risk of stroke is low enough that most patients can forgo blood thinners. The findings were published in the **New England Journal of Medicine** and were presented at the **American Heart Association (AHA) Scientific Sessions 2025** in New Orleans.
Traditionally, patients who underwent AF ablation were advised to continue taking oral anticoagulants, commonly referred to as blood thinners, even after successful treatment. This recommendation stemmed from uncertainty about whether the procedure itself sufficiently reduced stroke risk.
Significant Findings of the OCEAN Trial
According to **Dr. Atul Verma**, co-principal investigator of the trial and director of the Division of Cardiology at the **McGill University Health Centre**, “This is one of the most important clinical questions in modern electrophysiology, and the OCEAN trial gives us the answer we’ve been seeking.” He emphasized the importance of translating research into safer and simpler care for patients.
**Dr. David Birnie**, co-principal investigator and head of the Division of Cardiology at the **Ottawa Heart Institute**, highlighted the transformative potential of the study. “For the majority of the one million people each year who undergo catheter ablation for atrial fibrillation, this study is a game-changer,” he stated. The study found that one year after a successful ablation, the risk of stroke was so low that the disadvantages of continuing blood thinners outweighed the benefits.
The trial compared patients taking **rivaroxaban**, a commonly prescribed anticoagulant, with those taking low-dose **aspirin**. After three years, the rates of stroke and embolism in both groups were statistically similar and extremely low, comparable to those in individuals without a history of AF. Notably, patients who continued on blood thinners experienced more clinically significant bleeding events, highlighting the risks associated with unnecessary anticoagulation.
Collaboration and Future Implications
The OCEAN trial was conducted through a collaborative network of cardiovascular research centres across **56 sites** in **Canada**, **Europe**, **China**, and **Australia**. The entire study was coordinated by **Dr. George Wells** and his team at the **Ottawa Heart Institute’s Cardiovascular Research Methods Centre**. Dr. Wells noted, “This study is a testament to what can be achieved when researchers, clinicians, and institutions around the world work together toward a common goal.”
The findings from the OCEAN trial are expected to influence future clinical guidelines, potentially altering the treatment protocol for millions of patients globally who undergo catheter ablation for atrial fibrillation. The research was supported by various organizations, including **Bayer**, **Abbott**, **Biotronik**, and the **Canadian Institutes for Health Research**.
For patients and healthcare providers alike, this study marks a significant advancement in understanding the management of atrial fibrillation post-ablation, paving the way for safer treatment options. As Dr. Verma succinctly put it, the study’s outcome is not just an academic achievement but a profound step towards improving patient care on a global scale.
