Moderate Mitral Regurgitation in CABG Patients
Moderate Mitral Regurgitation in CABG Patients
Background:

 The presence of a mild to moderate ischemic mitral regurgitation (IMR) results in a
 significantly reduced long-term survival and increased hospitalizations for heart-failure.
 The benefit of adding mitral valve surgery to coronary artery by-pass surgery (CABG) is well
 documented in the combination of coronary artery disease and severe MR. On the other hand, it
 is clinical practice to refrain from repairing the mitral valve in those CABG cases where the
 IMR is mild to moderate. However, there are no conclusive data available to support this
 principle. The existing studies are small, retrospective, and the results contradictive. The
 need for a prospective randomized trial has frequently been proposed and discussed, however,
 to the best of our knowledge, such a study has not yet commenced.

 Study design:

 The Moderate Mitral Regurgitation In Patients Undergoing CABG (MoMIC) Trial is the first
 international multi-center, large-scale study to clarify whether moderate IMR in CABG
 patients should be corrected. A total of 550 CABG patients with moderate IMR are to be
 randomized to either CABG alone or CABG plus mitral valve correction.

 Implication:

 If correction of moderate MR in CABG patients is the superior strategy, this should be
 offered to all patients in this entity.
Inclusion Criteria:

 -  Patients with ischemic heart disease, who fulfil the indications for CABG, and who
 also have a moderate ischemic MR. Ischemic MR is defined as mitral regurgitation due
 to coronary artery disease and not fortuitously associated with it. It is caused
 either by a mitral annular dilatation (Carpentier type I), or a restrictive motion of
 the posterior mitral leaflet (Carpentier type IIIb), or a combination of these. The
 mitral leaflets should be slender and without signs of intrinsic organic disease. The
 mitral annulus should be with no significant calcification that can be held
 responsible for valve insufficiency. The severity of mitral regurgitation is
 quantified by means of echoardiography using the Proximal Isovelocity Surface Area
 (PISA)-method. Moderate MR is defined as a calculated ERO of 15-30 mm2 at rest .
 Hence, patients referred for CABG and showing signs of mitral regurgitation on
 auscultation, by echocardiography, or by ventriculography will further be evaluated by
 a thorough echocardiography (Transthoracic (TTE) in ambiguous cases supplemented by
 transesophageal echocardiography (TEE) before surgery, in order to determine whether
 the patient fulfil the inclusion criteria. In addition, ejection fraction (visually
 estimated), left atrial dimension, mitral annular and tricuspid annular size, as well
 as estimates of pulmonary hypertension will be recorded.

 -  Age ≥ 18 yrs.

 -  The inclusion is independent of the left ventricular function.

 -  The inclusion is independent of the left atrial size.

 -  It is mandatory that the patient is able to fully understand the written information,
 the purpose of the study, and able to give an informed consent.

 Exclusion Criteria:

 -  Patients with previous cardiac surgery.

 -  Emergency surgery.

 -  Malignant disease with an expected survival of less than 5 years.

 -  ST-elevation myocardial infarction within 16 days.

 -  Significant aortic valve disease necessitating aortic valve replacement

 -  Calcification of the ascending aorta.

 -  Significant mitral annular calcification.

 -  Type II MR (ruptured papillary muscle, or infracted elongated papillary muscle with
 prolapse)

 -  Refusal to participate in the study.