What is functional mitral regurgitation (MR)?

From the Guidelines

Functional mitral regurgitation is a condition where the mitral valve leaks blood backward into the left atrium during heart contraction despite having structurally normal valve leaflets, and its management should prioritize optimization of guideline-directed medical therapy (GDMT) before considering transcatheter mitral valve repair, as evidenced by the COAPT trial 1.

Definition and Pathophysiology

Functional mitral regurgitation occurs due to left ventricular dysfunction and remodeling that distorts the valve apparatus, typically happening in conditions like heart failure, coronary artery disease, or dilated cardiomyopathy, which cause the left ventricle to enlarge and change shape, as described in the European Heart Journal guidelines 1.

Treatment Approach

The treatment focuses on addressing the underlying heart condition through medications like ACE inhibitors, beta-blockers, and diuretics to reduce ventricular size and improve function, with surgical interventions such as mitral valve repair, replacement, or transcatheter procedures like MitraClip considered in severe cases, as outlined in the Journal of the American College of Cardiology update 1.

Key Considerations

• Optimization of GDMT is crucial before referring patients for transcatheter mitral valve repair, as it leads to reversal of cardiac remodeling, reduction of LV volumes, and a concomitant reduction in functional MR, as highlighted in the COAPT trial 1.
• The severity of functional mitral regurgitation directly correlates with worse heart failure symptoms and poorer prognosis, making early diagnosis and management essential, as noted in the European Heart Journal guidelines 1.
• Transcatheter mitral valve repair, such as MitraClip, may be beneficial in patients with optimized GDMT and persistent symptoms with severe MR, as shown in the COAPT study 1.

Management Strategy

The management strategy for functional mitral regurgitation should involve a multidisciplinary approach, including optimization of GDMT, consideration of transcatheter mitral valve repair, and careful patient selection, as recommended in the Journal of the American College of Cardiology update 1. Some key points to consider in the management of functional mitral regurgitation include:

• Optimization of GDMT, including the use of ACE inhibitors, beta-blockers, and diuretics, to reduce ventricular size and improve function.
• Consideration of transcatheter mitral valve repair, such as MitraClip, in patients with optimized GDMT and persistent symptoms with severe MR.
• Careful patient selection, taking into account factors such as the severity of MR, left ventricular function, and comorbidities.
• A multidisciplinary approach, involving cardiologists, cardiac surgeons, and other healthcare professionals, to ensure comprehensive care and optimal outcomes for patients with functional mitral regurgitation.

From the Research

Definition and Overview of Functional Mitral Regurgitation (MR)

• Functional mitral regurgitation (FMR) is a complex condition characterized by significant mitral regurgitation coexisting with cardiomyopathy and heart failure, carrying an increased risk for associated morbidity and mortality 2.
• FMR occurs as a result of global or segmental left ventricular (LV) dysfunction or left atrial dilatation, leading to mitral annular dilatation, papillary muscle displacement, mitral valve (MV) leaflet tethering, and leaflet remodeling 3.
• The condition can be broadly categorized into two main groups: ventricular and atrial, which often coexist, with ventricular FMR secondary to left ventricular remodeling and atrial FMR developing due to atrial and annular dilatation 4.

Pathophysiology and Prognosis

• The etiology of FMR is secondary to nonischemic or ischemic (postmyocardial infarction) adverse remodeling 5.
• FMR portends a poor prognosis, with even mild FMR associated with adverse clinical outcomes 3.
• The prevalence of FMR continues to rise in the United States, emphasizing the need for effective management strategies 3.

Treatment Options

• Guideline-directed medical therapy remains the cornerstone of initial treatment, with emphasis placed on treatment of the underlying LV dysfunction 6, 4.
• Cardiac resynchronization therapy and surgical correction of FMR are also considered, although surgical correction is controversial as it typically does not address the underlying mechanism and etiology of the condition 6.
• New, minimally invasive transcatheter therapies, such as the MitraClip system, have shown promise in the treatment of FMR in selected patients 2, 6, 5.
• Patients who remain symptomatic despite optimal medical therapy can be considered for surgical or percutaneous MV intervention 3.