Comparing the Effectiveness of a Mitral Valve Repair Procedure in Combination With Coronary Artery Bypass Grafting (CABG) Versus CABG Alone in People With Moderate Ischemic Mitral Regurgitation

Surgical Interventions for Moderate Ischemic Mitral Regurgitation

Coronary artery bypass grafting (CABG) is a procedure that people with coronary artery disease (CAD) may undergo to increase blood flow to the heart. During a CABG procedure, people who have a leak in one of the valves in the heart-the mitral valve-may at the same time undergo a procedure that repairs the valve. This study will evaluate whether people with moderate mitral valve leakage would be better off undergoing CABG plus the mitral valve repair procedure or undergoing CABG alone.

CAD occurs when the arteries that supply blood to the heart become blocked as a result of plaque buildup. In severe cases, CAD can cause chest pain, shortness of breath, and heart attack. CABG is one treatment option for people with CAD. During a CABG procedure, a healthy artery or vein from another part of the body is connected to the blocked coronary artery. Blood flow is then routed around the blockage to the heart.

After a heart attack, some people may have a leak in the mitral valve of the heart. This condition is known as ischemic mitral regurgitation (IMR) and is associated with poor health outcomes, including worsening heart failure. In people with severe mitral valve leakage, the CABG procedure and a mitral valve repair procedure are routinely performed together; however, in people with only moderate valve leakage, there is no consensus in the medical community as to whether the mitral valve repair procedure is beneficial at the time of CABG. The purpose of this study is to determine whether people with moderate mitral valve regurgitation should undergo a mitral valve repair procedure in addition to CABG or undergo CABG alone.

This study will enroll people with CAD who require a CABG procedure and have moderate mitral regurgitation. At a baseline study visit, participants will undergo a physical examination; blood collection; neurocognitive tests; and questionnaires regarding medical history, medication history, and quality of life. In the operating room, participants will be randomly assigned to undergo either CABG surgery and the mitral valve repair procedure or only CABG surgery. Blood, urine, and tissue samples may be collected from participants after the surgery; this is optional and will only be done with prior approval from participants. All participants will attend study visits at Months 6, 12, and 24. At each visit, participants will take part in a medication history review, a physical examination, an echocardiogram, a cardiopulmonary exercise test, neurocognitive tests, and quality of life surveys.

Inclusion Criteria:

• Moderate mitral regurgitation in the judgment of the clinical site echocardiographer, assessed by transthoracic echocardiogram. Assessment of mitral regurgitation will be performed using an integrative method (Zoghbi W. et al. J. American Society of Echocardiography. 2003:16:777-802. see appendix). Quantitative guidelines as proposed would be: ERO between 0.2 cmsq to 0.39 cmsq. If ERO < 0.2, then the degree of mitral regurgitation will be guided by other color Doppler quantitative methods (jet area/left atrial area ratio, vena contracta, supportive criteria in an integrated fashion
• CAD that is amenable to CABG and a clinical indication for revascularization
• Age ≥ 18 years

Exclusion Criteria:

• Any evidence of structural (chordal or leaflet) mitral valve disease
• Inability to derive ERO and end-systolic volume index (ESVI) by transthoracic echocardiography
• Planned concomitant intra-operative procedures (with the exception of closure of patent foramen ovale [PFO] or atrial septal defect [ASD]or Maze procedure or left atrial appendage excision)
• Prior surgical or percutaneous mitral valve repair
• Contraindication to cardiopulmonary bypass (CPB)
• Clinical signs of cardiogenic shock at the time of surgery
• Treatment with chronic intravenous inotropic therapy at the time of surgery
• Severe, irreversible pulmonary hypertension in the judgment of the investigator
• ST segment elevation myocardial infarction (MI) requiring intervention in the 7 days before surgery
• Congenital heart disease (except PFO or ASD)
• Evidence of cirrhosis or liver synthetic failure
• Recent history of psychiatric disease (including drug or alcohol abuse) that is likely to impair compliance with the study, in the judgment of the investigator
• Therapy with an investigational intervention at the time of screening, or planning to enroll in an additional investigational intervention study during participation in the study
• Any concurrent disease with a life expectancy of less than 2 years
• Pregnancy at the time of randomization