Tailored lower‑intensity blood thinner plan after left atrial appendage closure to prevent stroke
Official title: CLOT-LESS - CLOsure Tailored: LEss Antithrombotic Strategy After LAAC for Stroke Prevention
Run by National Medical Research Center for Therapy and Preventive Medicine · NCT07575867 · Data updated 2026-11-12
This project tests whether people with non‑valvular atrial fibrillation who get a left atrial appendage closure can stop blood thinners after taking low‑dose apixaban (2.5 mg twice daily) for 3 months, compared with people who stay on standard‑dose DOACs.
Quick facts
| Study type | Observational |
|---|---|
| Ages | 18 Years and up |
| Sex | All |
| Enrollment | 464 (estimated) |
| Sponsor | National Medical Research Center for Therapy and Preventive Medicine Government |
| Locations | 1 site (Moscow) |
| Status | Recruiting |
| Started | April 2026 |
| Main results expected | April 2032 |
| Study ends | April 2032 |
| Registry record updated | May 8, 2026 |
| Trial ID | NCT07575867 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Adults (≥18) with documented non‑valvular atrial fibrillation and CHA2DS2‑VASc score ≥3 for women or ≥2 for men who are candidates for LAAC or long‑term DOAC therapy and can tolerate at least 3 months of apixaban are ideal candidates.
✕Probably not a fit
Patients with other active indications for anticoagulation (e.g., mechanical valves, acute VTE), those requiring antiplatelet or P2Y12 therapy, those who cannot tolerate apixaban, or those with significant valvular disease are unlikely to benefit from the LAAC‑then‑withdrawal strategy.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
This is a prospective, non‑randomized observational cohort that enrolls adults with non‑valvular atrial fibrillation and follows them for 36 months. Patients undergoing left atrial appendage closure receive reduced‑dose apixaban (2.5 mg twice daily) for 3 months and, if imaging shows good device sealing without leak or device thrombosis, stop antithrombotic therapy thereafter. A control cohort of patients indicated for long‑term anticoagulation remains on standard full‑dose DOAC therapy and has the same schedule of follow‑up. Outcomes include a composite of major bleeding, all‑cause death, ischemic stroke, systemic embolism, and device‑related thrombus, with imaging checks by TEE or cardiac CT at 3, 6, and 12 months and telephone follow‑up through 36 months.
Why it matters
Potential benefit: If successful, this approach could let some patients avoid long‑term anticoagulation, lowering bleeding risk and medication burden while maintaining stroke protection.
How similar studies have gone: Left atrial appendage closure has been shown non‑inferior to oral anticoagulation for stroke prevention, but the specific strategy of short reduced‑dose apixaban followed by complete withdrawal is relatively novel and has limited direct trial evidence.
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria: * Age ≥18 years; * Documented nonvalvular AF (≥30 seconds on ECG within previous 12 months); * CHA2DS2-VASc score ≥3 for women and ≥2 for men; * Signed informed consent to participate in the study; Exclusion Criteria: * Active indication for anticoagulation OTHER than atrial fibrillation at the time of enrollment and/or the predicted/unpredicted occurrence of such indications during the entire study period (e.g., mechanical valve, acute VTE, recent PE requiring \>3 months anticoagulation); * Inability to tolerate at least 3 months of apixaban therapy (for LAAC arm); * Indications for antiplatelet therapy or therapy with P2Y12 inhibitors at the time of inclusion and/or the predicted/unpredicted occurrence of such indications during the entire study period; * The presence of mechanical prosthetic heart valves, mitral stenosis of severe or moderate degree; * Active DVT requiring anticoagulation; * Congenital or acquired haemostasis disorders, rheumatic heart disease or recurrent deep vein thrombosis; * Left ventricular ejection fraction (LVEF) \< 30%; * Glomerular filtration rate (GFR) \< 30 ml/min (stage IV or V chronic kidney disease) or dialysis patient; * Severe liver failure, including cirrhosis and Child-Pugh Class C/D; * NYHA class IV congestive heart failure; * The patient had a myocardial infarction - MI with or without ST segment elevation (STEMI, NSTEMI) with or without intervention, within 30 days before LAAC; * The patient had a stroke (of any cause, ischemic or hemorrhagic) within 30 days before LAAC; * Intracardiac thrombus before LAAC; * Major bleeding according to BARC criteria (type 3 and higher) within 30 days before LAAC or before randomization; * Amyloid cardiomyopathy; * Platelet count \< 100,000 x 109/l; * The patient participates in another study, with the exception of observational studies without therapeutic interventions; * Pregnant or breast-feeding patients, patients planning pregnancy during the study period; * The LAAC procedure was unsuccessful or interrupted for technical reasons; * PDL (peridevice leak) ≥ 3 mm; * Contraindications for one of the treatment regimens prescribed by the study protocol (including allergic reactions); * Planned cardiac or non-cardiac surgical procedure within 30 days before or 90 days after LAAC. Minor procedures not requiring discontinuation of antithrombotic therapy are permitted (e.g., cardioversion, catheter ablation, cataract surgery); * The patient has a heart tumor, active infection, signs of physiological tamponade; * The documented life expectancy of the patient is less than 12 months;
Where it's running
-
Federal State Budgetary Institution National Medical Research Center for Therapy and Preventive Medicine of the Ministry of Healthсare of the Russian Federation
Moscow, Russia Recruiting
Study contacts
- Principal investigator: Karapet Davtyan, Professor — Federal State Budgetary Institution National Medical Research Center for Therapy and Preventive Medicine of the Ministry of Healthсare of the Russian Federation
- Study coordinator: Timofey Brontveyn, Medical doctor
- Email: tbrontveyn.md@gmail.com
- Phone: +79150579995
Similar studies
Other studies for the same condition or treatment. Recruiting studies are listed first.
-
Concomitant Pulsed Field Ablation and Left Atrial Appendage Closure in AF Patients
In patients with atrial fibrillation who need both ablation and left atrial appendage closure, this study tests doing both procedures in a single intervention using FARAPULSE PFA and a WATCHMAN FLX device.
-
Comparing outcomes of left atrial appendage closure in patients with atrial fibrillation
This study looks at how well different methods of closing a part of the heart help people with atrial fibrillation and what factors might affect the results over time.
-
Registry documenting left atrial appendage closure procedures in Austria
This study is collecting information on patients with atrial fibrillation in Austria who have had a left atrial appendage closure procedure because they can't take blood thinners, to see how safe and effective the treatment is.
-
AI-based tools to help diagnose, treat and predict stroke outcomes across multiple hospitals
This study tests AI-powered tools on real-world stroke patients to see if they can improve pre-hospital triage, diagnosis, and outcome prediction while data stay securely within each hospital.
-
Simplified Tranexamic Acid Regimen for Trauma with Hemorrhage
This trial tests a simplified TXA dosing approach to see if it safely helps adults with major trauma and significant bleeding.
-
Left-atrial Fibrosis in Persistent Atrial Fibrillation and Its Comorbidities
This study tests how comorbid conditions like sleep apnea and primary aldosteronism relate to left-atrial fibrosis and AF recurrence in patients undergoing ablation.
How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.