MitraFix transcatheter mitral valve system for high-risk severe mitral regurgitation

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.