Safety and Effectiveness Study of SQ-Kyrin TMVr System for Functional Mitral Regurgitation

Inclusion Criteria: 1. Severe functional MR (FMR) ≥3+ as determined by transthoracic echocardiography (TTE); 2. Note: Eligible TTE must be obtained at least 30 days after the subject has been stabilized on optimal therapy (including Guideline Directed Medical Therapy GDMT). In the judgment of the center's cardiac team, subjects have received adequate treatment according to applicable criteria, including treatment for coronary artery disease, left ventricular dysfunction, MR, and heart failure (e.g., with cardiac resynchronization therapy (CRT or CRT-D), implantable cardioverter-defibrillator (ICD) implantation, coronary revascularization, and stable GDMT (see Appendix III for the definition of GDMT). 3. Age ≥ 18 years old, regardless of gender; 4. Cardiac function classification NYHA class II, III or ambulatory IV a; 5. At least one hospitalization for heart failure or subjects with high BNP \> 150 pg/ml or high NT-proBNP \> 600 pg/ml in the past 12 months. 6. Note: BNP or NT-proBNP must be obtained after the subject has stabilized on optimal therapy including Guideline Directed Medical Therapy (GDMT) at least 30 days. The patients can understand the purpose of the trial, voluntarily participate and sign an informed consent form, and are willing to undergo relevant tests and clinical follow-up. 7. Left ventricular end-systolic diameter (LVESD)≤70mm 8. The MR beam mainly originates from the A2/P2 area 9. Mitral valve coaptation depth≤11mm, coaptation height≥2mm, effective length of anterior and posterior leaflets\>10mm 10. Mitral valve effective orifice area (EOA) ≥ 4.0cm2 Exclusion Criteria: 1. History of mitral valve surgery; 2. Patients with infective endocarditis or suggestive of active infection; 3. Complicated with severe untreated coronary artery disease; 4. Patients with pulmonary hypertension (pulmonary systolic blood pressure\>70mmHg); 5. patients with transthoracic echocardiographic evidence of moderate-severe to severe right ventricular dysfunction; 6. Left heart ejection fraction \<20%; 7. Patients who are extremely frail and cannot tolerate general anesthesia surgery or is in the state of shock requiring circulatory support; 8. Patients diagnosed with hypertrophic cardiomyopathy, restrictive cardiomyopathy, constrictive pericarditis; 9. Severe renal insufficiency (eGFR ≤ 25 mL/min) or requiring chronic renal replacement therapy; 10. Patients with definite coagulation disorders and severe coagulation system diseases; 11. Patients with clear contraindications to the use of anticoagulants; 12. Patients with stroke or transient cerebral ischemic attack within 30 days; 13. Received cardiac pacemaker therapy or cardiac resynchronization therapy (CRT, CRT-D) or implanted cardioverter-defibrillator (ICD) implantation therapy within 30 days; 14. Any intracardiac mass, left ventricular or atrial thrombus detected on transthoracic echocardiography; 15. Severe tricuspid TR; 16. Patients with other valve disease requiring surgery or interventional therapy; 17. Patients with severe macrovascular disease requiring surgical treatment; 18. Severe symptomatic carotid stenosis (\>70% on ultrasonography) or carotid stenting within 30 days; 19. Patients with inappropriate anatomical structures of the heart and valves indicated by imaging examinations; 20. Known allergy to contrast agents and nickel-titanium memory alloy products; 21. \<Resting systolic blood pressure 90 mmHg or \>160 mmHg; 22. Patients with diseases that seriously affect the evaluation of treatment, such as patients with severe neurological lesions affecting cognitive ability, patients with malignant tumors, etc.; 23. Patient life expectancy \< 12 months; 24. Patients with severe thoracic deformity; 25. Women who are pregnant, breastfeeding, or planning to become pregnant within the next 12 months.