Comparison of Anti-Thrombotic Treatments Between Aspirin and Warfarin During Initial Six Months After Bioprpsthetic Heart Valve Replacement (CONCLAVE)

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).

Study Overview

• Status: Not yet recruiting
• Conditions: Valve Replacement Surgery
• Intervention / Treatment: Drug: Aspirin; Drug: Vitamin K antagonist(warfarin)

• Study Type: Interventional
• Enrollment (Estimated): 1058
• Phase: Phase 4

Contacts and Locations

• Study Contact: Name: YU-KYUNG CHOI, RN; Phone Number: 82224053814; Email: cyk1108@amc.seoul.kr

Study Locations

• Japan
  • Osaka, Japan, 565-0871
    • Osaka University Hospital
    • Contact: Yajima Shin, MD
  • Osaka, Japan, 564-8565
    • National Cerebral and Cardiovascular Center Hospital
    • Contact: Fukushima Satsuki, MD
• South Korea
  • Seoul, South Korea, 05505
    • Asan Medical Center
    • Contact: Joon-Bum KIM, MD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

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 hemodynamix 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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Aspirin; Antiplatelet Agent	Drug: Aspirin; 100mg 1 tablet once daily for 6 months
Active Comparator: wafarin; Vitamin K antagonist	Drug: Vitamin K antagonist(warfarin); Maintain an INR of 2.0 to 3.0 for 6 months

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
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 Outcome Measures

Outcome Measure	Time Frame
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

Collaborators and Investigators

• Sponsor: Asan Medical Center
• Investigators: Study Director: Joon-Bum KIM, MD, jbkim1975@amc.seoul.kr

Study record dates

Study Major Dates

• Study Start (Estimated): February 1, 2026
• Primary Completion (Estimated): October 31, 2030
• Study Completion (Estimated): March 31, 2031

Study Registration Dates

• First Submitted: December 11, 2025
• First Submitted That Met QC Criteria: February 20, 2026
• First Posted (Actual): February 25, 2026

Study Record Updates

• Last Update Posted (Actual): February 25, 2026
• Last Update Submitted That Met QC Criteria: February 20, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: aspirin versus vitamin K antagonists
• Additional Relevant MeSH Terms: Organic Chemicals; Hydrocarbons; Hydrocarbons, Cyclic; Hydrocarbons, Aromatic; Phenols; Benzene Derivatives; Salicylates; Hydroxybenzoates; Aspirin
• Other Study ID Numbers: 2025-1499

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No