Improving Mitral Repair for Functional Mitral Regurgitation
Improving Mitral Repair for Functional Mitral Regurgitation
The investigators are interested in determining the best surgical technique to correct
 functional mitral regurgitation, as there is currently not one technique that is established
 to work better than the other.

 The technique used in current clinical practice is undersizing mitral annuloplasty (UMA), in
 which a prosthetic ring is implanted onto the mitral valve to correct the leakage. Though
 widely adopted, durability of the repair is less, as 58% of the patients present with
 recurrent FMR within 2 years. There are no specific algorithms to predict who might have UMA
 failure, but research indicates that some geometric indices might be strong predictors. The
 investigators are interested in testing the hypothesis that, elevated lateral inter-papillary
 muscle separation (IPMS) is a predictor of post-UMA recurrence of FMR at 12 months. In the
 first part of this study, the study team will measure lateral IPMS before surgery, and relate
 to post-surgery FMR severity at discharge/30 days, 6 months and 12 months.

 A relatively newer technique is papillary muscle approximation (PMA), in which a suture draws
 together the two muscles that connect the mitral valve to the heart muscle prior to
 performing UMA. This reduces the lateral inter-papillary muscle separation (IPMS) and is
 expected to improve the durability of UMA. In the second part of this study, the
 investigators will perform PMA and UMA together and determine if FMR severity is reduced at
 discharge/30 days, 6 months and 12 months.
Functional mitral regurgitation (FMR) is a common heart valve lesion that is observed in
 patients suffering for cardiomyopathies. Timely surgical repair of FMR can reduce volume
 overload and potentially improve cardiac function. Durable surgical techniques for FMR repair
 are lacking. Undersizing mitral annuloplasty (UMA) is the current technique of choice, but
 its durability is quite poor. Thirty five percent of the repairs fail within one year and 58%
 fail within 2 years.

 One of the probable mechanisms causing UMA failure is elevated lateral inter-papillary muscle
 separation (IPMS). The study investigators are interested in understanding if the extent of
 lateral IPMS has a direct impact on the failure rates of UMA at 1 year post surgery.
 Secondly, the investigators are interested in determining if patients with elevated lateral
 IPMS benefit from papillary muscle approximation (PMA) along with UMA.

 The investigators are interested in determining the best way to correct functional mitral
 regurgitation, as there is currently not one technique that is established to better than the
 other. The most common repair technique is called undersizing mitral annuloplasty (UMA), in
 which a prosthetic ring is implanted onto the mitral valve to correct the leakage. Another
 more recent technique is papillary muscle approximation (PMA), in which a suture draws
 together the two muscles that connect the mitral valve to the heart muscle prior to
 performing UMA. In this research study, the study team is investigating whether they can
 identify those patients who will benefit from one repair over another.

 The primary objective of this protocol is to investigate if pre-operative IPMS is predictive
 of FMR severity at 12 months after UMA to repair FMR. Furthermore, whether a cut-off value of
 pre-operative inter-papillary muscle separation can be established to predict patients who
 might have failure of UMA.

 The secondary objective of this protocol is to investigate if adding PMA to UMA is an
 effective technique in reducing recurrence of FMR at 12 months post-procedure.
Inclusion Criteria:

 Patients with functional mitral regurgitation (FMR) from either ischemic or non-ischemic
 cardiomyopathies, referred for surgical or transcatheter mitral valve annuloplasty.
 Suitability for mitral annuloplasty is determined by the surgeon, using some or all the
 criteria described below:

 -  Left ventricular end diastolic diameter is less than or equal to 70mm.

 -  Systolic tenting height is less than or equal to 12mm

 -  Mitral regurgitation of moderate or greater severity, as defined by the guidelines of
 the American society of echocardiography at the time of the study approval (via a
 transthoracic echo).

 -  Cardiomyopathy of ischemic or non-ischemic origins, with or without the need for
 coronary revascularization.

 -  Able to sign informed consent and release of medical information forms, or able to
 assign a legal representative who can sign on the patient's behalf.

 Exclusion Criteria:

 -  Any evidence of structural (chordal or leaflet) mitral lesions.

 -  Planned concomitant intra-operative procedures (except for closure of patent foramen
 ovale or atrial septal defect)

 -  Planned concomitant intra-operative Maze procedure for symptomatic paroxysmal atrial
 fibrillation.

 -  Persistent atrial fibrillation

 -  Prior mitral valve repair

 -  Contraindication for cardiopulmonary bypass

 -  Clinical signs of cardiogenic shock at the time of randomization

 -  ST segment elevation myocardial infarction within 14 days prior to inclusion in this
 study.

 -  Congenital heart disease (except PFO or ASD)

 -  Chronic renal insufficiency defined by Creatinine ≥ 3.0 or chronic renal replacement
 therapy, who are contraindicated for cardiac surgery

 -  Recent history of psychiatric disease that is likely to impair compliance with the
 study protocol, in the judgement of the investigator

 -  Pregnancy at the time of randomization