Safety and Feasibility Study of the MitraFix® Transcatheter Mitral Valve System

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.