New device aims to seal off stroke risk without blood thinners
NCT ID NCT06580275
First seen Jun 27, 2026 · Last updated Jun 27, 2026
Summary
This study is testing a new device called CLAAS that is implanted in the heart to close off a small pouch (the left atrial appendage) where blood clots often form in people with atrial fibrillation. The goal is to reduce the risk of stroke without needing long-term blood thinners. About 80 adults with atrial fibrillation and a high stroke risk who cannot take blood thinners will receive the implant, and doctors will check if the device seals properly and is safe after 45 days.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- CLAAS device (a heart implant to close the left atrial appendage)
- What this could lead to
- If successful, this device could offer a safer, drug-free way to prevent strokes in people with atrial fibrillation who cannot use blood thinners.
- What could go wrong
- This is an early-stage study with only 80 participants and no comparison group, so results may not apply broadly. Risks include heart injury, stroke, bleeding, or the device not sealing properly.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Not a phased trial
Phase numbers describe drug development. The registry uses this when they do not apply, as it does for trials of devices, procedures or behaviour changes, and for observational studies.
- Participants
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About 80 people
The number the study aims to enrol. It can still change while the study runs.
- Started
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Sep 2024
- Expected to finish
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Sep 2026
An estimate. End dates often move.
- Lead sponsor
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A company
The lead sponsor is a pharmaceutical, biotech, or medical-device company.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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18 years and older
- Sex
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Anyone
- Healthy volunteers
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Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
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 CHADS2 score of ≥2 or CHA2DS2-VASc score of ≥3. 4. Has an appropriate rationale to seek a non-pharmacologic alternative to long-term oral anticoagulation including contraindications to long term oral anti-coagulation inclusive of history of intracranial bleed, subdural hematoma, gastrointestinal bleeding, hematuria, epistaxis, falls, and other less common conditions. Also included is the inability to reliably take medications and reluctance to take a blood thinner. 5. Deemed by 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 patient 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., prior atrial septal defect \[ASD\] or patent foramen ovale \[PFO\], surgical repair or implanted closure device, or obliterated or ligated left atrial appendage). 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 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 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 mechanical valve implant. 14. Renal insufficiency, defined as estimated glomerular filtration rate (eGFR) \<30mL/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 device materials (e.g., nickel, titanium) that would preclude any P2Y12 inhibitor therapy, or the patient 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 study. 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 (TEE) assessment or ICE guided imaging during the procedure. Imaging Exclusion Criteria: 1. Left atrial appendage anatomy which cannot accommodate the CLAAS device per manufacturer IFU (e.g., the anatomy and sizing must be appropriate for the test (CLAAS) device in order to be enrolled in the trial). 2. Intracardiac thrombus or dense spontaneous echo contrast consistent with thrombus, as visualized by pre-procedural imaging (TEE or Cardiac CT) or baseline procedural ICE prior to implant. 3. Left ventricular ejection fraction (LVEF) \<30%. 4. Moderate or large circumferential pericardial effusion \>10mm 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 \>15mm or length \>15mm) 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 \<1.5cm2). 8. Complex atheroma with mobile plaque of the descending aorta and/or aortic arch. 9. Evidence of cardiac tumor.
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
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Aarhus University Hospital, Skejby
Aarhus, DK-8200, Denmark
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Fondazione Toscana Gabriele Monasterio
Massa, 54100, Italy
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Na Homolce Hospital
Prague, 150 30, Czechia
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University Hospital of Copenhagen
Copenhagen, DK-2100, Denmark
More trials for these conditions
Other studies related to the condition(s) this trial covers.
- Heart hole or stroke trigger? global registry tracks who gets closure and what happens next
- Two ways to quiet a racing heart: trial pits hybrid ablation against standard catheter treatment
- Stroke's hidden heart rhythm clue under investigation
- Suture device may get heart patients walking sooner after leg vein procedures
- Two ways to catch a hidden heart rhythm after stroke
- Can an implanted heart monitor catch hidden irregular heartbeats after stroke?