Tailored lower‑intensity blood thinner plan after left atrial appendage closure to prevent stroke

CLOT-LESS - CLOsure Tailored: LEss Antithrombotic Strategy After LAAC for Stroke Prevention

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
• Enrollment: 464 (estimated)
• Ages: 18 Years and up
• Sex: All
• Sponsor: National Medical Research Center for Therapy and Preventive Medicine (other gov)
• Locations: 1 site (Moscow)
• Trial ID: NCT07575867 on ClinicalTrials.gov

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.

Who should consider this trial

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.

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.

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 performed: 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.

Eligibility 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 this trial is running

Moscow

• 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

Conditions: Atrial Fibrillation, Stroke Prevention in Patients With Atrial Fibrillation, Left Atrial Appendage Closure, Hemorrhage, Anticoagulants / Administration & Dosage, Reduced-dose Apixaban, Thromboembolism, atrial fibrillation