Transcatheter edge-to-edge repair (TEER) has emerged as an important therapy for severe mitral regurgitation. Current guidelines lack evidence-based recommendations for optimal postprocedural antithrombotic strategies, leading to heterogeneous clinical practices. And there are no randomized controlled trials (RCTs) available to compare different antithrombotic strategies following TEER. STAR-TEER trial is an investigator-initiated, multicenter, randomized, parallel controlled, open-label trial, aiming to assess the safety and efficacy of de-escalated antithrombotic strategies with monotherapy in post-TEER patients with or without indications for oral anticoagulation (OAC) respectively. This trial plans to enroll 1,912 patients stratified into 2 cohorts: patients in Cohort A (requiring long-term OAC, n = 880) will be randomized 1:1 to rivaroxaban monotherapy or rivaroxaban plus clopidogrel, and patients in Cohort B (no OAC indication, n = 1,032) will be randomized 1:1 to aspirin monotherapy or aspirin plus clopidogrel. The primary outcome is all bleeding complications within 12 months post-TEER. The 2 key secondary outcomes are nonprocedure-related bleeding within 12 months post-TEER (key secondary outcome 1) and a composite of ischemic events including all-cause mortality, stroke, systemic embolism, and myocardial infarction within 12 months post-TEER (key secondary outcome 2). A hierarchical hypothesis testing will be performed, with the primary outcome and key secondary outcome 1 tested for superiority, followed by the key secondary outcome 2 tested for noninferiority. The STAR-TEER trial is the first large randomized controlled trial (RCT) to stratify patients based on OAC indication and compare different antithrombotic strategies following TEER in these 2 distinct cohorts. URL: https://www. gov. Unique identifier: NCT06901466 (Cohort A), NCT07007143 (Cohort B).