Inclusion Criteria:
* Age 18 years or older.
* Symptomatic, moderate to severe or severe, functional or mixed, mitral regurgitation (≥ Grade 3+).
* NYHA functional Class ≥ II. If Class IV, patient must be ambulatory.
* Ability to tolerate oral anticoagulation.
* Ability to qualify for bailout surgery (which may include open heart surgery).
* High risk for open-heart mitral valve surgery due to age, co-morbidities or frailty, as determined by the Heart Team.
* Willing and able to complete study-related assessments and questionnaires.
Exclusion Criteria:
* Purely degenerative (organic/primary) (i.e. intrinsic valve lesions) mitral regurgitation.
* Excessive frailty or comorbid conditions that preclude the anticipated benefit of the mitral valve replacement.
* Life expectancy \<1 yr. due to noncardiac conditions.
* Endocarditis in the 3 months prior to procedure date.
* Current admission with acute heart failure exacerbation.
* Dependency on inotropic agents or mechanical circulatory support.
* Untreated clinically significant CAD.
* Active systemic infection.
* Modified Rankin Scale ≥4 disability.
* Chronic renal failure defined as eGFR \< 30 mL/min/m2 or on renal replacement therapy.
* Severe pulmonary arterial hypertension (PAH), defined as PASP \> 70mmHg.
* Platelets \< 90,000.
* COPD on home oxygen therapy deemed too high risk for intubation.
* Refuses blood transfusions.
* Documented bleeding or coagulation disorders (hypo- or hyper-coagulable states).
* Severe connective tissue disease under chronic immunosuppressive or cortisone therapy.
* Participating in other investigational studies likely to confound the results or affect the study.
* Unable or does not sign the study informed consent form.
* Patients classified as "vulnerable patients"
Cardiovascular Exclusion Criteria
* Myocardial infarction during prior 30 days.
* Stroke or TIA during prior 90 days.
* Severe extracardiac arteriopathy (safety measure for extra-circulatory support if surgical conversion is needed).
* Prior mitral valve treatment (e.g., valve repair or replacement, MitraClip, etc.), and/or anticipated mitral valve treatment prior to enrollment.
* Prior surgical mechanical valve AVR.
* Prior TAVI. -Need for any planned cardiovascular surgery or intervention (other than for MV disease) within 30 days post-index procedure.
* CRT, CRT-D, IPG or ICD implanted in previous 30 days.
* Cardiogenic shock, hemodynamic instability, Systolic Blood Pressure \<90mmHg, Inotropic dependent or IABP/mechanical circulatory support.
CABG or PCI within previous 30 days.
* Inadequately treated for cardiac condition per applicable standards, such as for coronary artery disease, left ventricular dysfunction, mitral regurgitation, or heart failure, as reviewed by the Patient Screening Committee.
* Prior or planned heart transplantation (UNOS status 1).
* Physical evidence of right-sided CHF:
1. Patients with ascites.
2. Patients with anasarca (generalized edema / hydropsy).
* Hypertrophic cardiomyopathy, restrictive cardiomyopathy, constrictive pericarditis, or other structural heart disease causing heart failure with the exception of dilated ischemic or non-ischemic cardiomyopathy.
Procedural Exclusion Criteria
* Known hypersensitivity or contraindication to procedural or post-procedural medication (e.g., contrast solution, anticoagulation therapy).
* Documented hypersensitivity to nickel or titanium.
Cardiac Imaging Exclusion Criteria (evaluated by Core Labs)
* Contraindications to TEE imaging
* Left ventricular EF ≤ 30% by echocardiogram.
* Severe mitral annular calcification, severe mitral stenosis, valvular vegetation or mass.
* Extensive mitral flail leaflets
* Evidence of new or untreated intracardiac thrombus, mass, or vegetation.
* Severe right ventricular dysfunction.
* Severe tricuspid regurgitation.
* Hemodynamically significant inter-atrial shunt (ASD).
* Severe aortic regurgitation or aortic stenosis.
* Anatomic ineligibility for SATURN Valve or SATURN TS procedure as determined by the Screening Committee.
