A Clinical Evaluation of the Safety and Effectiveness of the MitraClip® System for the Treatment of Functional Mitral Regurgitation in Symptomatic Heart Failure Subjects (COAPT Recruitment Closed). COAPT CAS (Recruitment Closed)

• Symptomatic functional MR (≥3+) due to cardiomyopathy of either ischemic or non-ischemic etiology determined by assessment of a qualifying transthoracic echocardiogram (TTE) obtained within 90 days and transesophageal echocardiogram (TEE) obtained within 180 days prior to subject registration, with MR severity based principally on the TTE study, confirmed by the Echocardiography Core Lab (ECL). The ECL may request a transesophageal echocardiogram (TEE) to confirm MR etiology.

• Note: Functional MR requires the presence of global or regional left ventricular wall motion abnormalities, which are believed to be the primary cause of the MR. If a flail leaflet or other evidence of degenerative MR is present, the subject is not eligible even if global or regional left ventricular systolic dysfunction is present.

• Note: Qualifying TTE must be obtained after the subject has been stabilized on optimal therapy including Guideline Directed Medical Therapy (GDMT) and at least 30 days after:

‣ a greater than 100% increase or greater than 50% decrease in dose of GDMT

‣ revascularization and/or implant of Cardiac Resynchronization Therapy device (CRT or CRT-D) or reprogramming of an implanted CRT or CRT-D that results in increased biventricular pacing (from \<92% to ≥92%)

• In the judgment of the HF specialist investigator at the site, the subject has been adequately treated per applicable standards, including for coronary artery disease, left ventricular dysfunction, mitral regurgitation and heart failure (e.g., with cardiac resynchronization therapy, revascularization, and/or GDMT). The Eligibility Committee must also concur that the subject has been adequately treated.

• New York Heart Association (NYHA) Functional Class II, III or ambulatory IV.

• The Local Site Heart Team (CT surgeon and HF specialist investigators) and the Central Eligibility Committee concur that surgery will not be offered as a treatment option and that medical therapy is the intended therapy for the subject, even if the subject is randomized to the Control group.

• The subject has had at least one hospitalization for heart failure in the 12 months prior to subject registration and/or a corrected brain natriuretic peptide (BNP) ≥300 pg/ml or corrected n-Terminal pro- brain natriuretic peptide NT-proBNP ≥1500 pg/ml measured within 90 days prior to subject registration (corrected refers to a 4% reduction in the BNP or NT-proBNP cutoff for every increase of 1 kg/m2 in BMI above a reference BMI of 20 kg/m2).

• Note: BNP or NT-proBNP must be obtained after the subject has been stabilized on GDMT and at least 30 days after:

‣ a greater than 100% increase or greater than 50% decrease in dose of GDMT

‣ revascularization and/or implant of Cardiac Resynchronization Therapy device (CRT or CRT-D) or reprogramming of an implanted CRT or CRT-D that results in increased biventricular pacing (from \<92% to ≥92%).

• Left Ventricular Ejection Fraction (LVEF) is ≥20% and ≤50% within 90 days prior to subject registration, assessed by the site using any one of the following methods: echocardiography, contrast left ventriculography, gated blood pool scan or cardiac magnetic resonance imaging (MRI).

• Note: The method must provide a quantitative readout (not a visual assessment).

• The primary regurgitant jet is non-commissural, and in the opinion of the MitraClip implanting investigator can be successfully be treated by the MitraClip. If a secondary jet exists, it must be considered clinically insignificant.

• Creatine Kinase-MB (CK-MB) obtained within prior 14 days \< local laboratory Upper Limit of Normal (ULN).

• Transseptal catheterization and femoral vein access is determined to be feasible by the MitraClip implanting investigator.

⁃ Age 18 years or older.

⁃ The subject or the subject's legal representative understands and agrees that should he/she be assigned to the Control group, he/she will be treated with medical therapy and conservative management without surgery and without the MitraClip, either domestically or abroad. If the subject would actively contemplate surgery and/or MitraClip if randomized to Control, he/she should not be registered in this trial.

⁃ The subject or the subject's legal representative has been informed of the nature of the trial and agrees to its provisions, including the possibility of randomization to the Control group and returning for all required post-procedure follow-up visits, and has provided written informed consent.

⁃ Left Ventricular End Systolic Dimension (LVESD) is ≤ 70 mm assessed by site based on a transthoracic echocardiographic (TTE) obtained within 90 days prior to subject registration.

∙ For the CPX Sub-study: Subjects have to meet the COAPT study eligibility criteria to be registered in the CPX Sub-study.

∙ COAPT CAS study Inclusion Criteria:

• Subjects must meet all of the above COAPT RCT inclusion criteria, and must have national Medicare coverage by the Centers for Medicare and Medicaid Services (CMS).