The goal of this early feasibility clinical trial is to test a new device called the MitraFix® Transcatheter Mitral Valve System. It aims to learn if the device is safe and if it can help adults who have a severe leaky heart valve (mitral regurgitation). This study is for people who are at high risk for traditional open-heart surgery.

The main questions it aims to answer are:

Is the MitraFix system safe for participants? Can the device be successfully placed in the heart? Does the device help reduce the valve leak and improve daily life?

Participants will:

Receive the MitraFix valve through a small tube inserted into a vein in the leg.

Visit the clinic for heart tests, walking tests, and health checks for up to one year after the procedure.

Inclusion Criteria:

• Moderate to severe or severe (≥3+) mitral regurgitation.
• Age ≥ 18 years.
• Patients at high risk for traditional open-heart surgery, defined as: STS mortality risk for mitral valve replacement ≥ 8%; OR presence of 2 or more frailty indices; OR presence of 2 or more major organ dysfunctions that cannot be improved post-operatively; OR other comorbidities or factors making them unsuitable for surgery.
• Anatomically suitable for transcatheter MitraFix® system implantation via a transfemoral-transseptal approach as assessed by the investigator; the transfemoral-transseptal access route meets the requirements of the delivery system.
• Able to understand the study purpose, voluntarily participate, sign the informed consent form, and willing to accept relevant examinations and clinical follow-ups.

Exclusion Criteria:

• Severe mitral stenosis.
• Severe calcification of mitral leaflets and/or annulus; anatomical structures of the mitral valve apparatus (e.g., papillary muscles) unsuitable for device implantation.
• High risk of left ventricular outflow tract obstruction (LVOTO) based on pre-operative CT/TEE planning (estimated neo-LVOT < 150 mm²), which cannot be avoided by procedural optimization.
• Presence of previous implants in the mitral position (surgical bioprosthetic or mechanical valves, surgical annuloplasty rings, etc.).
• Infective endocarditis or evidence of active infection.
• Stroke or transient ischemic attack (TIA) within 90 days.
• Severe untreated coronary artery disease or acute myocardial infarction within 90 days; or percutaneous coronary intervention (PCI)/coronary stent implantation within 90 days.
• Severe pulmonary hypertension (resting PASP > 70 mmHg, assessed as irreversible).
• Severe right ventricular dysfunction: Tricuspid Annular Plane Systolic Excursion (TAPSE) < 17 mm.
• Concomitant tricuspid valve, aortic valve, or severe great vessel disease requiring surgical or interventional treatment.
• Left ventricular ejection fraction (LVEF) < 30%.
• Extreme frailty preventing tolerance of the procedure, or in a state of shock requiring circulatory support.
• Implantation of CRT, CRT-D, or implantable cardioverter-defibrillator (ICD) within 30 days.
• Chronic dialysis or expected need for long-term dialysis; or severe renal impairment (e.g., eGFR < 30 mL/min/1.73m²) unable to undergo perioperative dialysis.
• Documented coagulopathy or severe hematological disorders (e.g., platelet count < 50×10^9/L, active bleeding), or history of heparin-induced thrombocytopenia (HIT).
• Contraindications to anticoagulant/antiplatelet therapy that cannot be substituted or bridged.
• Echocardiographic evidence of any intracardiac mass, or thrombus in the left ventricle or left atrium (including left atrial appendage).
• Contraindications to transesophageal echocardiography (TEE).
• Severe allergy to iodine contrast media, nitinol, bovine-derived materials, or other device materials that remains intolerable despite premedication.
• Life expectancy < 12 months.
• Pregnant or breastfeeding women.
• Unsuitable for the transfemoral-transseptal approach (e.g., femoral vein diameter, calcification, tortuosity, or atrial septum/left atrial anatomy not meeting delivery system requirements).
• Participation in another clinical study of an investigational device or drug within 3 months prior to screening that may interfere with this study.
• Any other conditions deemed unsuitable for enrollment by the investigator.