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

Inclusion Criteria: * Severe MR ≥3+ as determined by transthoracic echocardiography (TTE); * STS risk score results show that patients at high risk for traditional surgery or patients who cannot tolerate traditional thoracotomy: Subjects judged to be refractory to mitral valve surgery due to a ≥ 8% risk of death from STS surgery for surgical mitral valve replacement, or a ≥ 6% risk of death from STS surgery for surgical mitral valve repair, or because of any of the following risk factors: 1. Porcelain aorta or active ascending aortic plaque 2. Mediastinum treated with radiotherapy 3. Past mediastinitis 4. Left ventricular ejection fraction (LVEF) \<40% 5. Presence of a patent coronary bypass implant 6. Acceptance of two or more cardiothoracic surgeries 7. Liver cirrhosis 8. Other surgical risk factors * Patients with Degenerated MR (Degenerated MR); * Age ≥ 18 years old, regardless of gender; * Classification of cardiac function: NYHA class II, III or ambulatory class IV; * Patients assessed by a multidisciplinary cardiac team as very high-risk or unsuitable for routine mitral valve surgery; * Be able to understand the objective of the trial, and volunteered to participate and signed the Informed Consent Form, willing to accept the relevant examination and clinical follow-up. * Left ventricular end-systolic diameter (LVESD)≤60mm * The MR beam mainly originates from the A2/P2 area * Mitral valve disease prolapse lesion area width≤15mm, prolapse height≤10mm, effective length of anterior and posterior valve leaflets\>10mm * Mitral valve effective orifice area (EOA) ≥ 4.0cm2 * No obvious calcification of mitral valve leaflets * Patient anatomy allows atrial septum approach Exclusion Criteria: * History of mitral valve surgery; * Patients with infective endocarditis or suggestive of active infection; * Complicated with severe untreated coronary artery disease; * Patients with pulmonary hypertension (pulmonary systolic blood pressure\>70mmHg); * Patients with transthoracic echocardiographic evidence suggesting moderate-severe to severe right ventricular dysfunction; * Left ventricular ejection fraction \<20%; * Patients who are extremely frail and cannot tolerate general anesthesia surgery or is in the state of shock requiring circulatory support; * Patients diagnosed with hypertrophic cardiomyopathy, restrictive cardiomyopathy, constrictive pericarditis; * Mitral regurgitation due to active rheumatic heart disease or rheumatic etiology; * Severe renal insufficiency (eGFR ≤ 25 mL/min) or requiring chronic renal replacement therapy; * Patients with definite coagulation disorders and severe coagulation system diseases; * Patients with clear contraindications to the use of anticoagulants; * Patients with stroke or transient cerebral ischemic attack within 30 days; * Any intracardiac mass, left ventricular or atrial thrombus detected on transthoracic echocardiography; * Severe tricuspid TR; * Patients with other valve disease requiring surgery or interventional therapy; * Patients with severe macrovascular disease requiring surgical treatment; * Severe symptomatic carotid stenosis (\>70% on ultrasonography) or carotid stenting within 30 days; * Patients with inappropriate anatomical structures of the heart and valves indicated by imaging examinations; * Known allergy to contrast agents and nickel-titanium memory alloy products; * R\<testing systolic blood pressure 90 mmHg or \>160 mmHg; * 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.; * Patient life expectancy \< 12 months; * Patients with severe thoracic deformity; * Women who are pregnant, breastfeeding, or planning to become pregnant within the next 12 months.