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Comparing Amulet LAA occluder to NOAC therapy for atrial fibrillation patients

Clinical Trial of Atrial Fibrillation Patients Comparing Left Atrial Appendage Occlusion Therapy to Non-vitamin K Antagonist Oral Anticoagulants

NA · Abbott Medical Devices · NCT04226547

This study tests whether the Amulet LAA occluder device is safer and more effective than blood-thinning medications for people with atrial fibrillation who are at risk for strokes.

Quick facts

PhaseNA
Study typeInterventional
Enrollment2650 (estimated)
Ages18 Years and up
SexAll
SponsorAbbott Medical Devices (industry)
Locations132 sites (Birmingham, Alabama and 131 other locations)
Trial IDNCT04226547 on ClinicalTrials.gov

What this trial studies

This trial aims to assess the safety and effectiveness of the Amulet LAA occluder device compared to non-vitamin K oral anticoagulants (NOACs) in patients with non-valvular atrial fibrillation who are at increased risk for ischemic stroke. Participants will be randomly assigned in a 1:1 ratio to receive either the Amulet device or a NOAC, with the specific NOAC chosen at the discretion of the study physician. The study is designed as a prospective, multicenter trial conducted worldwide, focusing on long-term outcomes for patients requiring anticoagulation therapy.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18 and older with documented non-valvular atrial fibrillation and a CHA2DS2-VASc score indicating a high risk of stroke.

Not a fit: Patients who require long-term oral anticoagulation therapy for conditions other than atrial fibrillation may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide a safer and more effective alternative to long-term NOAC therapy for patients with atrial fibrillation.

How similar studies have performed: Other studies have shown promise in using left atrial appendage occlusion devices, suggesting potential success for this approach.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

* Documented paroxysmal, persistent, or permanent non-valvular AF (documentation must include an electrocardiogram, Holter, or event recorder)
* At high risk of stroke or systemic embolism, defined as a CHA2DS2-VASc score of ≥ 2 for men and ≥ 3 for women
* Eligible for long-term NOAC therapy
* Able to comply with the required NOAC medication regimen if randomized to the Control Group
* Able to comply with the required medication regimen post-device implant if subject is randomized to the Device Group or subject is a Roll-in
* Able to understand, and is willing to provide, written informed consent to participate in the trial, prior to any clinical investigation related procedure or assessment
* 18 years of age or older, or the age of legal consent
* Able and willing to return for required follow-up visits and assessments

Exclusion Criteria:

* Requires long-term OAC therapy for a condition other than AF
* Planned cardiac intervention or surgery, which is invasive or requires sedation or anesthesia, within 3 months following randomization, other than study-related procedures such as LAAO and cardiac imaging (if applicable)
* Known contraindication to, or allergic to, aspirin, clopidogrel, or OAC medication use
* Indicated for P2Y12 platelet inhibitor for \>1 year post-randomization
* In the opinion of the investigator, is considered at high risk for general anesthesia and general anesthesia is planned for the study procedure
* Has undergone atrial septal defect (ASD) repair or has an ASD closure device present
* Has undergone patent foramen ovale (PFO) repair or has a PFO closure device implanted
* Is implanted with a mechanical valve prosthesis
* Is implanted with an inferior vena cava filter
* History of rheumatic or congenital mitral valve heart disease
* Has any of the customary contraindications for a percutaneous catheterization procedure (e.g. subject is too small to accommodate the ICE probe (if planned) or required catheters, or subject has active infection or bleeding disorder)
* Customary contraindications for TEE/TOE (e.g., presence of esophageal varices, esophageal stricture, or history of esophageal cancer)
* Experienced stroke or transient ischemic attack (TIA) within 90 days prior to randomization or implant procedure (as applicable)
* Underwent any cardiac or non-cardiac intervention or surgery within 30 days prior to randomization
* Underwent catheter ablation for AF or atrial flutter within 60 days prior to randomization
* Experienced myocardial infarction within 90 days prior to randomization
* New York Heart Association Class IV Congestive Heart Failure
* Left ventricular ejection fraction ≤ 30% (per most recent assessment)
* Symptomatic carotid disease (defined as \> 50% lumen diameter narrowing on CTA, MRA, or TCD with symptoms of ipsilateral transient or visual TIA evidenced by amaurosis fugax, ipsilateral hemispheric TIAs or ipsilateral stroke); if subject has a history of carotid stent or endarterectomy the subject is eligible if there is \< 50% lumen diameter narrowing
* Has known intracranial atherosclerosis and/or intracranial small vessel disease (defined as 6 points on the Fazekas Scale)
* Reversible cause of AF (i.e., secondary to thyroid disorders, acute alcohol intoxication, trauma, recent major surgical procedures)
* History of idiopathic or recurrent venous thromboembolism
* LAA is obliterated or surgically ligated
* Thrombocytopenia (defined as \< 50,000 platelets per microliter (\<50 x 10\^9 /L)or anemia (defined as hemoglobin \< 10 g/dL) requiring transfusions
* Hypersensitivity to any portion of the device material or individual components of the Amulet LAA occluder device (e.g., nickel allergy)
* Actively enrolled in, or plans to enroll in, a concurrent clinical study in which the active treatment arm may confound the results of this trial
* Is pregnant or breastfeeding, or pregnancy is planned during the course of the investigation
* Active endocarditis or other infection producing bacteremia
* Transient case of AF (i.e., never previously detected, provoked/induced by surgical or catheter manipulations, etc.)
* Severe renal failure (estimated glomerular filtration rate \<30 ml/min/1.73m2), but not on dialysis
* Life expectancy is less than 2 years in the opinion of the Investigator
* Presence of other anatomic or comorbid conditions, or other medical, social, or psychological conditions that, in the Investigator's opinion, could limit the subject's ability to participate in the clinical investigation or to comply with follow up requirements, or impact the scientific soundness of the clinical investigation results.

Where this trial is running

Birmingham, Alabama and 131 other locations

+82 more sites — see ClinicalTrials.gov for the full list.

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Atrial Fibrillation, Stroke, Bleeding

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.