Comparison of Anti-Thrombotic Treatments Between Aspirin and Warfarin During Initial Six Months After Bioprosthetic Heart Valve Replacement

NCT07431762 — Phase 4, Recruiting, 1058 participants, Asan Medical Center

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Registry	NCT07431762, acronym CONCLAVE
Status	Recruiting
Phase	Phase 4
Study type	Interventional; randomized, parallel, masking: none, treatment
Enrollment	1058 (Estimated)
Sponsor	Asan Medical Center (Other)
Conditions	Valve Replacement Surgery
Interventions	Aspirin, Vitamin K antagonist(warfarin) (Drug)
Dates	start 2026-06-05, primary completion 2030-10-31 (estimated), completion 2031-03-31 (estimated), first posted 2026-02-25, last updated 2026-07-06
Locations	3 sites in Japan, South Korea

-Summary

This trial is a multinational, multicenter, randomized, open-label, active-controlled clinical trial comparing the safety of aspirin versus vitamin K antagonists (warfarin) as oral antithrombotic therapy during the initial 6 months following tissue valve replacement (aortic or mitral).

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+Arms and interventions

Arm	Type	Interventions	Description
Aspirin	Experimental	Drug: Aspirin	Antiplatelet Agent
warfarin	Active comparator	Drug: Vitamin K antagonist(warfarin)	Vitamin K antagonist

Aspirin (Drug): 100mg 1 tablet once daily for 6 months
Vitamin K antagonist(warfarin) (Drug): Maintain an INR(International Normalized Ratio) of 2.0 to 3.0 for 6 months

+Outcome measures

Primary outcomes

A composite endpoint is defined as a single outcome that combines multiple clinical events; the occurrence of any one of the component events is considered as meeting the endpoint. [From registration to 6 months]

Secondary outcomes

Rate of all-cause mortality within 6 months [From registration to 6 months]
Number of participants who experienced stroke within 6 months [From registration to 6 months]
Number of participants who experienced transient ischemic attack within 6 months [From registration to 6 months]
Number of participants who experienced systemic embolism within 6 months [From registration to 6 months]
Number of participants who experienced myocardial infarction within 6 months [From registration to 6 months]
Number of participants who experienced major bleeding within 6 months [From registration to 6 months]
Number of participants with valve thrombosis at 6 months [From registration to 6 months]

+Eligibility

Sex: All, ages: 19 Years to any

Inclusion Criteria:

1. Aged ≥ 19 years with successful surgical bioprosthetic valve replacement
2. Bioprosthetic heart valve in aortic or mitral valve positions, for a day postoperatively
3. The patient or guardian agrees to the study protocol and the schedule of clinical follow-up, and provides informed, written consent, as approved by the appropriate Institutional Review Board/Ethical Committee of the respective clinical site.

Exclusion Criteria:

1. Mechanical valve in any heart valve position
2. Previous hemorrhagic stroke within the last 3 months
3. Clinically overt stroke within the last 3 months
4. Current need for anticoagulation (i.e. atrial fibrillation, deep vein thrombosis)
5. Unstable postoperative conditions at index point (i.e. requirement mechanical hemodynamic support, disabling complications, stroke \[ischemic, embolic\], hemorrhagic stroke)
6. Hypersensitivity to the main component or constituents of aspirin or vitamin K antagonist
7. Pregnant or lactating women

+Locations (3)

Facility	City	Country	Status
National Cerebral and Cardiovascular Center Hospital	Osaka	Japan	Not yet recruiting
Osaka University Hospital	Osaka	Japan	Not yet recruiting
Asan Medical Center	Seoul	South Korea	Recruiting

+Investigators

Joon-Bum KIM, MD, Study director, jbkim1975@amc.seoul.kr