Improving Mitral Repair for Functional Mitral Regurgitation

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.