Mitral Regurgitation in Heart Failure

The following are key points to remember from this review on mitral regurgitation (MR) in heart failure (HF) and its treatment:

1. Secondary or functional MR is commonly seen in HF with reduced ejection fraction (HFrEF) patients and is a poor prognostic marker. Available therapies that improve outcomes in this population include cardiac resynchronization therapy (CRT), left ventricular (LV) assist devices, and cardiac transplantation. In contrast, surgery for secondary MR is not supported by existing evidence and is being supplanted by transcatheter treatments after the recent MITRA-FR and COAPT trials.
2. The MITRA-FR trial, based out of France, randomized 307 patients with HFrEF and severe functional MR to optimal medical therapy versus optimal therapy and MitraClip. Reduction of MR to grade 2+ at discharge was achieved in 92% of patients, but had no impact on all-cause mortality or HF rehospitalization at 1 year.
3. The COAPT trial was based out of the United States and randomized 614 patients with symptomatic HFrEF and moderate-severe MR to MitraClip and optimal medical therapy versus optimal medical therapy only. Patients with Stage D HF or severe LV dilatation >7 cm were excluded. Implementation of optimal therapy including CRT was supervised by the core committee.
4. In COAPT, 98% of patients achieved a successful reduction in MR, and MitraClip in combination with medical therapy demonstrated a statistically significant reduction in HF hospitalization (number needed to treat of 3.1) and a reduction in 2-year all-cause mortality.
5. Differences between the results of these two trials can be explained by differences in patient characteristics, trial design, and duration of follow-up. The COAPT trial excluded patients with Stage D HF and severe LV dilatation (>7 cm), enrolled patients with more severe MR, mandated a run-in period on maximal medical therapy with demonstration of persistent symptoms, and had a longer follow-up period of 2 years. Rates of procedural complications in COAPT were lower.
6. Appropriate patient selection is an important factor to take into consideration when evaluating patients for transcatheter mitral therapies. Patients with extreme LV dilatation and less severe secondary MR are unlikely to benefit from this therapy.
7. Other key takeaway points from these trials include poor prognosis in patients with secondary MR and HFrEF despite optimal medical therapy: two-thirds of the control group had an HF hospitalization and 50% of patients died within 2 years.
8. The COAPT trial also highlights the importance of a team-based approach in management of this patient population with a close synergy between HF specialists and interventional cardiologists. Apart from appropriate patient selection, this trial highlights early MitraClip referral for those with persistent symptoms on optimal medical therapy to reduce mortality and HF rehospitalizations.