Stopping DOACs After Successful AF Ablation Feasible in Low-risk Patients: OCEAN

All experts warned that the trial results don’t apply to higher-risk groups.

NEW ORLEANS, LA—There is no difference in the risk of stroke and other adverse outcomes among patients treated with aspirin and those treated with oral anticoagulation following successful ablation for atrial fibrillation (AF), results of the OCEAN trial show.

Rates of stroke, systemic embolism, and small cerebral infarctions detected by MRI were similar in patients treated with aspirin and those treated with the direct oral anticoagulant rivaroxaban (Xarelto; Bayer/Janssen) over 36 months of follow-up, investigators reported today during a late-breaking presentation at the American Heart Association 2025 Scientific Sessions.

“I think when you look at the totality of the evidence, there are some patients who can stop oral anticoagulation after successful ablation,” lead investigator Atul Verma, MD (McGill University Health Centre, Montreal, Canada), said during a morning press conference.

“In my opinion, if they have a CHA2DS2-VASc score of 1, 2, or even 3, they can probably stop,” Verma continued. “The only caveat to that is that [OCEAN] didn’t have a lot of patients with recent strokes, so if their CHA2DS2-VASc is 2 because of a recent stroke, that may be a different category of patient.”

The recent ALONE-AF study also found that, for patients who underwent successful AF ablation, stopping oral anticoagulation was associated with better clinical outcomes than remaining on treatment.

Current US and European guidelines recommend sticking with oral anticoagulation long-term after catheter ablation for AF on the basis of a patient’s calculated stroke risk. Whether it’s possible to stop oral anticoagulation has been frequently debated, but until recently, there’s been little evidence to guide treatment decisions.  

“Every single patient asks, can I get off my blood thinner?” Verma told TCTMD. “That’s why we went ahead and did the trial. We got the same question over and over and over, and we didn’t have an answer. We just decided we have to try to answer it.”

Electrophysiologist Oussama Wazni, MD (Cleveland Clinic, OH), agreed that physicians frequently are asked to make decisions around continuing or stopping oral anticoagulation in patients who have undergone AF catheter ablation. Based on OCEAN and ALONE-AF, for lower-risk patients who remain in normal sinus rhythm “it is a reasonable” consideration to stop the medication, said Wazni.

Despite the data, it remains a difficult decision when dealing with patients in real-world practice, he said. 

“We really have to have a good conversation with them,” Wazni told TCTMD. “We’ve all seen patients who have a CHA2DS2-VASc score of 0 and then a few months down the road they have a stroke. It’s happened. We’ve seen it in our practice. That’s why you need to present the data and have a discussion with them about what we can do.”

Christine Albert, MD (Cedars-Sinai Medical Center, Los Angeles, CA), who discussed the trial following the late-breaking presentation, said anticoagulation is usually continued long-term in nearly all patients after ablation given concerns about silent AF and the risk of stroke. In trials of older antiarrhythmic drugs, such as AFFIRM, there were persistent stroke risks in older patients thought to be in normal sinus rhythm, she said.

OCEAN, said Albert, provides important risk-benefit data that doctors can now use in discussions with their patients. For those who are a year out from a successful ablation and have a low-to-moderate risk of stroke, these new data suggest they may not need to continue with oral anticoagulation, said Albert.

Aspirin and Modified Rivaroxaban Dose

The OCEAN trial, which was published simultaneously in the New England Journal of Medicine, included 1,284 patients (mean age 66 years; 71.5% male) who had undergone successful AF catheter ablation at least 1 year prior to randomization and had a CHA2DS2-VASc score of 1 or more (2 or more for women or those with vascular disease). Two-thirds of patients had paroxysmal AF and the mean CHA2DS2-VASc score was 2.2.

Patients were randomized to treatment with 70 to 120 mg of aspirin daily, depending on availability, or a modified 15-mg dose of rivaroxaban at a median of 16.4 months after catheter ablation.  

OCEAN’s data safety and monitoring board recommended stopping the trial in 2022 because of a high likelihood there’d be no difference in outcomes between the two arms.

At 3 years, the primary composite outcome of stroke, systemic embolism, or new covert embolic stroke detected by MRI occurred in 0.8% patients treated with rivaroxaban and 1.4% in patients treated with aspirin, a nonsignificant difference (RR 0.56; 95% 0.19-1.65).

“We were surprised by the incredibly low event rates that were observed in both of the arms,” said Verma, noting the annualized risks of the primary endpoint were 0.33% and 0.66% in the rivaroxaban and aspirin arms, respectively.

The rate of stroke alone occurred in 0.8% of the rivaroxaban-treated patients and 1.1% of those in the aspirin group (RR 0.72; 95% CI 0.23-2.25). New covert embolic strokes occurred in just two patients in the aspirin arm, and there were no systemic embolisms. Cerebral infarcts measuring less than 15 mm occurred in 3.9% of patients in the rivaroxaban group and 4.4% of those in the aspirin arm, a nonsignificant difference (RR 0.89; 95% CI 0.51-1.55).

Fatal or major bleeding, the study’s primary safety endpoint, occurred in 1.6% of patients in the rivaroxaban group and 0.6% of those treated with aspirin (HR 2.51; 95% CI 0.79-7.95).

The trial was started 10 years ago, said Verma, and at that time, investigators didn’t feel comfortable randomizing patients to “nothing at all.” For that reason, they selected aspirin as the comparator arm to rivaroxaban. However, in the last decade, the thinking around aspirin has “soured,” he said, and there’s no evidence it reduces stroke risk in low-risk patients, which makes it more like the placebo used in the ALONE-AF trial.

Patient Conversations

Michael Ghannam, MD (University of Michigan Health, Ann Arbor), an electrophysiologist who wasn’t involved in the study, said there is plenty of evidence showing that ablation is effective for reducing AF burden and improving quality of life, but that the impact on stroke risk is less defined. 

“The current guidelines suggest that the patients should remain on anticoagulants,” Ghannam told TCTMD. “There are some lines of evidence that suggest that a lower burden of AF is associated with a lower risk of stroke, but we really don’t have the strength of evidence and adequate prospective studies to overturn the guideline recommendations.”

The OCEAN study, he said, answers an important clinical question as the prevalence of AF increases in our aging population and use of catheter ablation grows. The population reflects “real-world” practice given the broad inclusion criteria, although the overall baseline risk of stroke was modest, said Ghannam.

“I certainly wouldn’t use these data to justify discontinuing anticoagulants at large, particularly among patients who have a high burden of cardiovascular disease and elevated stroke risk,” he said. “Nevertheless, it’s interesting to see that the overall event rates postablation were low, which is something we’ve seen other randomized trials.”

For low-risk patients who have had a successful ablation, “we can have a more serious conversation with patients about getting off these blood thinners, particularly in patients who are at high risk for bleeding,” Ghannam advised.

To TCTMD, Wazni said that one option for physicians wary of stopping oral anticoagulation might be to use apixaban (Eliquis; Bristol Myers Squibb) after catheter ablation because it’s associated with less bleeding than the other DOACs. He also pointed out that bleeding, even major bleeding, is reversible in most cases but a stroke can be devastating.

Last year, Wazni presented results from OPTION, a study that suggested left atrial appendage occlusion (LAAO) might be an option when performed at the time of ablation or in a sequential manner. In that study, LAAO was associated with less bleeding and similar risks of all-cause mortality, stroke, or systemic embolism versus DOAC therapy over 3 years of follow-up.