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

Recruiting now

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

In brief

This is a prospective, non-randomized, observational cohort study conducted at the FSBI "NMRC TPM" of the Ministry of Healthcare of the Russian Federation. Left atrial appendage closure (LAAC) has been shown to be non-inferior to oral anticoagulation for preventing cardioembolic events in patients with atrial fibrillation. However, the optimal post-procedural antithrombotic regimen following LAAC remains unclear, with no consensus on evidence-based therapy. Given current trends in cardiology favoring reduced-intensity antithrombotic strategies, this study aims to contribute to the evidence base by evaluating whether LAAC followed by reduced-dose apixaban (2.5 mg BID) for 3 months with subsequent complete withdrawal of antithrombotic therapy is superior to long-term standard-dose DOAC therapy in patients with non-valvular atrial fibrillation.

Key facts

Study ID

NCT07575867

Run by

National Medical Research Center for Therapy and Preventive Medicine

People needed

464

Starts

2026-04-01

Expected to finish

2032-04-01

Last updated by the study team

2026-05-08

Who can join

Age: 18 and older. Sex: any. Healthy volunteers: not accepted.

You may qualify if…

• 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;

You may not qualify if…

• 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 is 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 (enrolling)

Full record on ClinicalTrials.gov

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