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Study on Long-Term Anticoagulation with Rivaroxaban vs. Acetylsalicylic Acid for Patients at Risk of Stroke After Atrial Fibrillation Ablation

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on patients who have undergone a procedure called catheter ablation to treat atrial fibrillation, a condition that can increase the risk of having a stroke. The study is investigating two different treatments to see which is more effective in reducing the risk of stroke and other related events. The first treatment involves the use of a medication called rivaroxaban, which is a type of blood thinner that helps prevent blood clots. The second treatment uses acetylsalicylic acid, commonly known as aspirin, which is also used to prevent blood clots but works in a different way.

The purpose of the study is to determine whether continuing long-term treatment with rivaroxaban is better than using acetylsalicylic acid alone in preventing strokes and other similar events in patients who are at moderate risk after their successful catheter ablation. Participants in the study will be randomly assigned to receive either rivaroxaban or acetylsalicylic acid. Some participants may receive a placebo, which looks like the real medication but does not contain any active ingredients. The study will last for up to 36 months, during which time participants will have regular check-ups and tests to monitor their health and the effects of the treatment.

The main goal is to see if there is a difference in the occurrence of strokes or other related events between the two treatment groups. The study will also look at other outcomes, such as the occurrence of bleeding, changes in brain scans using MRI, and overall quality of life. This information will help doctors understand the best way to prevent strokes in patients who have had atrial fibrillation and have undergone catheter ablation.

The research process

The trial runs in 4 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Enrollment

    The trial begins with the enrollment of patients who meet specific criteria. These include being at least one year post-successful catheter ablation for atrial fibrillation, having a CHA2DS2-VASc risk score of 1 or more, being over 18 years of age, and having non-valvular atrial fibrillation.

  2. Step 2

    Medication administration

    Participants will receive either ongoing, long-term oral anticoagulation or antiplatelet therapy alone. The medications used are acetylsalicylic acid (ASS-ratiopharm® 100 mg tablets) and rivaroxaban (Xarelto 15 mg film-coated tablets). Both medications are taken orally.

  3. Step 3

    Monitoring and assessments

    Throughout the trial, participants will undergo regular monitoring to assess the effectiveness of the treatment. This includes evaluating the occurrence of stroke, systemic embolism, and covert embolic stroke through cerebral magnetic resonance imaging (MRI).

    Secondary assessments include monitoring for clinical stroke, covert MRI strokes larger than 15 mm, bleeding events, transient ischemic attacks, and overall mortality. Additional evaluations involve neuropsychological testing and quality of life assessments.

  4. Step 4

    Completion

    The trial is expected to conclude by July 31, 2025. At the end of the trial, data will be analyzed to determine the net clinical benefit of the treatment strategies, focusing on the reduction in stroke and transient ischemic attack rates compared to major bleeding events.

Who can join the trial?

4 criteria

  • The patient must be at least one year after a successful procedure called catheter ablation for a heart condition known as atrial fibrillation. This means there should be no signs of irregular heartbeats, confirmed by specific heart tests called Holter and ECG, at different times after the procedure.
  • The patient must have a CHA2DS2-VASc risk score of 1 or more. This is a score used to estimate the risk of stroke in people with atrial fibrillation. However, if the only risk factors are being female or having vascular disease, the patient cannot participate.
  • The patient must be older than 18 years.
  • The patient must have a type of atrial fibrillation that is not caused by a problem with the heart valves, known as non-valvular atrial fibrillation.

Who cannot join the trial?

7 criteria

  • Patients who have had a recent **stroke** or **mini-stroke** (also known as a **transient ischemic attack** or TIA). A stroke is when blood flow to a part of the brain is stopped, and a mini-stroke is a temporary period of symptoms similar to those of a stroke.
  • Patients with a history of **bleeding disorders**. These are conditions that affect the way your blood clots, which can lead to excessive bleeding.
  • Patients who have **severe liver disease**. The liver is an organ that helps with digestion and filtering toxins from the blood, and severe disease can affect its function.
  • Patients with **kidney disease** that requires dialysis. Dialysis is a treatment that does the work of the kidneys if they are not functioning properly.
  • Patients who are pregnant or breastfeeding. Pregnancy and breastfeeding involve changes in the body that can affect how treatments work.
  • Patients who are unable to follow the study procedures or take the study medication as required. This means they might not be able to attend appointments or take the medication as instructed.
  • Patients who are participating in another clinical trial. Being in more than one trial at a time can affect the results of the study.
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Investigated drugs

  • Oral Anticoagulation

    is a type of medication used to prevent blood clots. In this trial, it is being tested to see if it is more effective than antiplatelet therapy in reducing the risk of stroke or other embolic events in patients who have undergone catheter ablation for atrial fibrillation. This medication works by thinning the blood, which helps to prevent clots from forming.

  • Antiplatelet Therapy (ASA)

    , commonly known as aspirin, is used to prevent blood clots by stopping platelets from clumping together. In this trial, it is being compared to oral anticoagulation to determine if it is sufficient on its own to reduce the risk of stroke or other embolic events in patients after catheter ablation for atrial fibrillation.

What is already known about the treatment

  • Warfarin

    Warfarin is an oral medication used to prevent blood clots, commonly administered in tablet form. It is well-established in medical literature as an anticoagulant, particularly for patients at risk of stroke due to atrial fibrillation. The main therapeutic indication for Warfarin is to reduce the risk of stroke and other clot-related issues. It works by inhibiting vitamin K-dependent clotting factors, which are essential for blood clot formation. Warfarin is classified as a vitamin K antagonist.

  • Aspirin (ASA)

    Aspirin is an oral medication typically taken in tablet form, used to reduce pain, fever, and inflammation, and as an antiplatelet agent to prevent blood clots. In medical literature, it is recognized for its role in reducing the risk of heart attacks and strokes. The main therapeutic indication in this context is to prevent cerebral embolic events in patients with atrial fibrillation. Aspirin works by inhibiting the enzyme cyclooxygenase, which in turn reduces the formation of thromboxane, a molecule that promotes platelet aggregation. It is classified as a nonsteroidal anti-inflammatory drug (NSAID) and an antiplatelet agent.

Investigated diseases

Atrial Fibrillation – Atrial fibrillation is a common heart rhythm disorder where the heart's upper chambers (atria) beat irregularly and often rapidly. This irregular rhythm can lead to poor blood flow and increase the risk of blood clots forming in the heart. These clots can travel to other parts of the body, including the brain, potentially causing a stroke. The condition may be persistent or occur in episodes, and symptoms can include palpitations, fatigue, and shortness of breath. Over time, atrial fibrillation can weaken the heart and lead to heart failure. It is often associated with other heart-related conditions such as high blood pressure or heart disease.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-518736-37-00Protocol codeOHIRC-20150866Estimated enrolment1 284 patientsSponsorUniversity Of Ottawa Heart Institute

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On this site, “treatment” means an investigational medicine being studied in a clinical trial. Its safety and efficacy for the use being studied have not yet been confirmed, some participants may receive a placebo or a comparator medicine, and taking part does not guarantee any health benefit. The decision to take part is made by the doctor at the research site. This site is for information only and does not replace medical advice.

This service is not affiliated with the European Commission, the EMA, or the official CTIS system. Most information comes from publicly available international clinical-trial registries, supplemented by data from academic sites, national regulators and commercial sponsors. On this site, “treatment” and “therapy” mean a medicine being tested in a clinical trial. Its safety and effectiveness in the use being studied are not yet confirmed, some participants may receive a placebo or a comparator, and taking part does not guarantee a health benefit. The doctor at the research site decides who can take part. This site provides information, not medical advice. Certain content and visual elements on this website have been generated or enhanced using artificial intelligence (AI).