This trial aims to evaluate the safety and efficacy of the Structural Heart Surgery Assist System in assisting TEER for patients with moderate-to-severe or greater degenerative or functional mitral regurgitation (MR ≥3+). A prospective, multicenter, stratified randomized controlled design with non-inferiority comparison will be used. The experimental group will utilize the Structural Heart Surgery Assist System, while the control group will undergo manual TEER (e.g., MitraClip G4).

Inclusion Criteria:

1. Age ≥18 years, regardless of gender.

2. Symptomatic moderate-to-severe or greater mitral regurgitation (MR ≥3+) confirmed by transthoracic and/or transesophageal echocardiography (TTE/TEE), with planned transcatheter edge-to-edge repair (TEER):

   For degenerative mitral regurgitation (DMR):

   -Deemed high-risk for surgical intervention by the heart team:STS score ≥8% for mitral valve replacement (MVR) mortality risk; ≥6% for mitral valve repair mortality risk; OR presence of ≥2 frailty indices (moderate-to-severe frailty); OR anatomical/technical barriers to surgery; OR ≥2 major organ dysfunctions unlikely to improve postoperatively; OR other high-risk factors per heart team assessment.OR patient declines surgery.

   For functional mitral regurgitation (FMR):

   • Persistent heart failure symptoms (NYHA Class III/IVa) despite guidelines directed medical therapy (GDMT), revascularization, or cardiac resynchronization therapy (CRT) for 1-3 months.
   • ≥1 hospitalization for heart failure within the past 12 months and/or BNP >150 pg/mL or NT-proBNP >600 pg/mL.
   • Left ventricular ejection fraction (LVEF) ≥20% and ≤50%, with left ventricular end-systolic diameter (LVESD) ≤70 mm.

3. Primary regurgitant jet is non-commissural and deemed treatable by the investigator (secondary jets, if present, must be clinically insignificant).

4. Volunteerly provides informed consent, understands the trial objectives, and agrees to comply with follow-up.

Exclusion Criteria:

1. Rheumatic mitral valve disease.
2. Uncorrected active infection.
3. Severe calcification or thickening in the clip coaptation zone, rendering TEER anatomically unsuitable.
4. Intracardiac mass, thrombus, or vegetation on echocardiography.
5. Severe right heart dysfunction (e.g., lower extremity edema with elevated jugular venous pressure and hepatomegaly) or severe pulmonary hypertension (echocardiographic systolic pulmonary artery pressure >70 mmHg).
6. Severe left heart dysfunction (LVEF <20%).
7. Acute myocardial infarction (AMI) within 30 days prior to the procedure.
8. Recent CABG, PCI, or TAVR within 30 days prior to the procedure.
9. Planned tricuspid/aortic valve or major vascular intervention within 30 days post-procedure.
10. Prior surgical or transcatheter mitral valve repair/replacement.
11. Thrombosis in access vessels (e.g., femoral vein, inferior vena cava) impeding catheter advancement.
12. Stroke/TIA within 30 days or severe carotid stenosis (>70% by ultrasound).
13. Cardiomyopathies or conditions including hypertrophic, restrictive, or infiltrative cardiomyopathy (e.g., amyloidosis, hemochromatosis, sarcoidosis), constrictive pericarditis, or active endocarditis.
14. Hemodynamic instability: Systolic blood pressure <90 mmHg without afterload-reducing agents, cardiogenic shock, requirement for intra-aortic balloon pump (IABP) or hemodynamic support.
15. Implanted pacemaker, CRT, or ICD within 30 days prior to the procedure.
16. End-stage heart failure (ACC/AHA Stage D), post-heart transplant, or listed for transplant.
17. Hypersensitivity or contraindications: ntolerance to anticoagulants, antiplatelet agents, or anesthesia, allergy to mitralclip materials (nickel/titanium, cobalt, chromium, polyester), severe contrast allergy precludes intervention.
18. Pregnant or breastfeeding.
19. Participation in other clinical trials (drug/device) without meeting primary endpoints.
20. Other contraindications per investigator judgment.