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Evaluating the CLAAS device for atrial fibrillation treatment

An Evaluation of the Safety and Effectiveness of the Conformal CLAAS System for Left Atrial Appendage Occlusion

Not applicable Interventional Conformal Medical, Inc · NCT05147792

This study is testing a new device called CLAAS to see if it works as well as two other devices for treating atrial fibrillation and reducing stroke risk in patients.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment1600 (estimated)
Ages18 Years and up
SexAll
SponsorConformal Medical, Inc Industry-sponsored
Locations88 sites (Birmingham, Alabama and 87 other locations)
Trial IDNCT05147792 on ClinicalTrials.gov

What this trial studies

This trial assesses the safety and efficacy of the CLAAS® device in patients with non-valvular atrial fibrillation by comparing its performance to the established WATCHMAN® and Amulet™ left atrial appendage closure devices. Eligible participants will be randomized to receive one of these devices and will be monitored for 5 years post-implantation. The study aims to determine if the CLAAS device is non-inferior to the existing options, providing a potential alternative for patients seeking non-pharmacologic solutions to reduce stroke risk.

Who should consider this trial

Good fit: Ideal candidates include adults aged 18 and older with documented non-valvular atrial fibrillation and a high risk of stroke.

Not a fit: Patients who are not at high risk of stroke or those who are not suitable for left atrial appendage closure may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide a new, effective device for patients with atrial fibrillation, potentially reducing their risk of stroke.

How similar studies have performed: Other studies have successfully evaluated similar left atrial appendage closure devices, indicating a promising avenue for this approach.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

1. Male or non-pregnant female aged ≥18 years
2. Documented non-valvular AF (paroxysmal, persistent, or permanent)
3. High risk of stroke or systemic embolism, defined as CHA2DS2-VASc score of ≥ 3
4. Has an appropriate rationale to seek a non-pharmacologic alternative to long-term oral anticoagulation
5. Deemed by the site investigator to be suitable for short term oral anticoagulation therapy but deemed less favorable for long-term oral anticoagulation therapy.
6. Deemed appropriate for LAA closure by the site investigator and a clinician not a part of the procedural team using a shared decision-making process in accordance with standard of care
7. Able to comply with the protocol-specified medication regimen and follow-up evaluations
8. The subject (or legally authorized representative, where allowed) has been informed of the nature of the study, agrees to its provisions, and has provided written informed consent approved by the appropriate institutional review board (IRB)/Regional Ethics Board (REB)/Ethics Committee (EC).

Exclusion Criteria:

1. Pregnant or nursing patients and those who plan pregnancy in the period up to one year following the index procedure. Female patients of childbearing potential must have a negative pregnancy test (per site standard test) within 7 days prior to index procedure.
2. Anatomic conditions that would prevent performance of an LAA occlusion procedure (e.g., atrial septal defect (ASD) requiring closure, high-risk patent foramen ovale (PFO) requiring closure, a highly mobile inter-atrial septal aneurysm precluding a safe TSP, presence of a PFO/ASD closure device, history of surgical ASD repair or history of surgical LAAO closure)
3. Atrial fibrillation that is defined by a single occurrence or that is transient or reversible (e.g., secondary thyroid disorders, acute alcohol intoxication, trauma, recent major surgical procedures)
4. A medical condition (other than atrial fibrillation) that mandates long-term oral anticoagulation (e.g., history of unprovoked deep vein thrombosis or pulmonary embolism, or prosthetic mechanical heart valve)
5. History of bleeding diathesis or coagulopathy, or patients in whom antiplatelet and/or anticoagulant therapy is contraindicated
6. Documented active systemic infection
7. Symptomatic carotid artery disease (defined as \>50% stenosis 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% stenosis noted at the site of prior treatment
8. Recent (within 30 days of index procedure) or planned (within 60 days post-procedure) cardiac or major non-cardiac interventional or surgical procedure
9. Recent (within 30 days of index procedure) stroke or transient ischemic attack
10. Recent (within 30 days of index procedure) myocardial infarction
11. Vascular access precluding delivery of implant with catheter-based system
12. Severe heart failure (New York Heart Association Class IV)
13. Prior cardiac transplant, history of mitral valve replacement or transcatheter mitral valve intervention, or any prosthetic mechanical valve implant
14. Renal insufficiency, defined as estimated glomerular filtration rate (eGFR) \<30 mL/min/1.73 m2 (by the Modification of Diet in Renal Disease equation)
15. Platelet count \<75,000 cells/mm3 or \>700,000 cells/mm3, or white blood cell count \<3,000 cells/mm3
16. Known allergy, hypersensitivity or contraindication to aspirin, heparin, or that would preclude any P2Y12 inhibitor therapy, or to device materials (e.g., nickel, titanium), or the subject has contrast sensitivity that cannot be adequately pre-medicated
17. Actively enrolled or plans to enroll in a concurrent clinical study in which the active treatment arm may confound the results of this trial
18. Unable to undergo general anesthesia
19. Known other medical illness or known history of substance abuse that may cause non-compliance with the protocol or protocol-specified medication regimen, confound the data interpretation, or is associated with a life expectancy of less than 5 years
20. A condition which precludes adequate transesophageal echocardiographic assessment

Echo exclusion criteria:

1. Left atrial appendage anatomy which cannot accommodate a commercially available control device or the CLAAS Implant per manufacturer IFU (e.g., the anatomy and sizing must be appropriate for both the investigational (CLAAS) and a commercially available device in order to be enrolled in the trial)
2. Intracardiac thrombus or dense spontaneous echo contrast consistent with thrombus, as visualized by TEE
3. Left ventricular ejection fraction (LVEF) \<30%
4. Moderate or large pericardial effusion \>10 mm or symptomatic pericardial effusion, signs or symptoms of acute or chronic pericarditis, or evidence of tamponade physiology
5. Atrial septal defect that warrants closure
6. High risk patent foramen ovale (PFO), defined as an atrial septal aneurysm (excursion \>15 mm or length \> 15 mm) or large shunt (early \[within 3 beats\] and/or substantial passage of bubbles, e.g., \>20)
7. Moderate or severe mitral valve stenosis (mitral valve area \<1.5 cm2)
8. Complex atheroma with mobile plaque of the descending aorta and/or aortic arch
9. Evidence of cardiac tumor

Where this trial is running

Birmingham, Alabama and 87 other locations

+38 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 → Find more trials like this →
Conditions Atrial FibrillationStroke
Last reviewed 2026-06-13 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.