What is the management approach for mitral regurgitation?

Management of Mitral Regurgitation

The management of mitral regurgitation fundamentally depends on distinguishing primary (degenerative) from secondary (functional) MR, as this determines whether surgery or medical therapy is the primary treatment approach. 1, 2

Initial Diagnostic Assessment

Echocardiography is mandatory to classify MR as primary versus secondary, determine severity, and guide all subsequent management decisions. 2, 3

Severity Criteria

• Severe primary MR: EROA ≥0.4 cm², regurgitant volume ≥60 mL/beat, regurgitant fraction ≥50%, vena contracta ≥7 mm 1, 2
• Severe secondary MR: EROA ≥0.3 cm² (if elliptical orifice), or ≥0.4 cm², regurgitant volume ≥45-60 mL/beat depending on flow conditions 1
• Use CMR when echocardiographic measurements are uncertain or ambiguous to quantify LV/RV function, chamber size, and detect myocardial fibrosis for prognostication 1, 2

Functional Assessment

• Perform exercise echocardiography in patients reporting exertional symptoms to unmask dynamic MR worsening, elevated pulmonary pressures, or inadequate ventricular response 1, 2
• BNP/NT-proBNP levels help guide timing of intervention in asymptomatic severe MR 1, 2
• Six-minute walk test provides objective functional capacity assessment, particularly valuable in elderly or frail patients 1

Management Algorithm for Primary (Degenerative) MR

Symptomatic Severe Primary MR

Surgery is indicated for ALL symptomatic patients with severe primary MR regardless of left ventricular ejection fraction. 1, 2

• Mitral valve repair is strongly preferred over replacement when anatomically feasible, as repair reduces mortality by approximately 70% compared to replacement 2
• Surgery must be performed at a heart valve center with documented high repair rates and low operative mortality 2

Asymptomatic Severe Primary MR

Surgery is indicated when LVEF falls to ≤60% OR LV end-systolic diameter reaches ≥40 mm, even without symptoms 2

• Do not delay surgery once these thresholds are reached, as irreversible LV dysfunction develops rapidly beyond these cutpoints 2
• Progressive LV dysfunction on serial imaging (≥3 studies showing increasing size or decreasing EF) warrants early intervention 1
• LA volume index ≥60 mL/m² may indicate surgery when LVEF >60% and LVESD <40 mm, particularly in low-risk patients at experienced centers 1

Role of Transcatheter Therapy in Primary MR

Transcatheter edge-to-edge repair (TEER) is reserved ONLY for high surgical risk patients with prohibitive operative risk and suitable valve morphology. 1, 2

• TEER should NOT be used as first-line therapy in surgical candidates with primary MR 2

Management Algorithm for Secondary (Functional) MR

First-Line Medical Therapy (Mandatory)

Guideline-directed medical therapy (GDMT) is the mandatory first step for ALL patients with secondary MR before considering any intervention. 1, 2, 3

Core GDMT Components:

• ACE inhibitors or ARBs reduce MR severity and improve outcomes, including reduced hospitalization and mortality 2, 3, 4
• Beta-blockers lessen MR, prevent LV function deterioration, and improve survival in moderate-to-severe MR 5, 2
• Mineralocorticoid receptor antagonists (aldosterone antagonists) for heart failure symptoms 2, 3
• Diuretics as first-line for fluid overload manifestations including lower extremity edema 2, 3
• Nitrates for acute dyspnea in patients with large dynamic MR component 2, 3

Cardiac Resynchronization Therapy

CRT should be implemented in patients meeting guideline criteria (LVEF ≤35%, QRS ≥150 ms, LBBB), as it reduces MR severity through improved papillary muscle synchronization 2, 3

Reassessment After Medical Optimization

MR severity MUST be reassessed after optimizing medical therapy, as secondary MR is dynamic and may improve substantially with GDMT 3

Indications for Intervention in Secondary MR

TEER for Secondary MR

TEER should be considered for patients meeting ALL of the following criteria: 1, 2

• Severe secondary MR persisting despite optimal GDMT
• LVEF 20-50%
• LV end-systolic diameter ≤70 mm
• NYHA class II-IV symptoms (or ambulatory class IV)
• Heart failure hospitalization within previous year OR elevated natriuretic peptides
• Suitable valve anatomy for TEER
• PASP <70 mmHg
• No severe RV dysfunction

Surgery for Secondary MR

Surgery is indicated when severe secondary MR is present AND the patient is undergoing CABG with LVEF >30%. 1, 2

• Moderate MR at time of CABG also warrants concomitant mitral surgery according to some guidelines 1

Surveillance Protocols

Asymptomatic Severe MR

Clinical and echocardiographic follow-up every 6-12 months 1, 2

Moderate MR

Clinical evaluation every 6-12 months with annual echocardiography 2, 3

Mild MR

Monitoring every 3-5 years 2

Multidisciplinary Heart Team Approach

ALL intervention decisions require multidisciplinary heart team discussion considering valve morphology, MR etiology, comorbidities, surgical risk, frailty, and procedure-specific factors 1, 2

Critical Pitfalls to Avoid

• Do NOT delay surgery in primary MR once LVEF ≤60% or LVESD ≥40 mm - irreversible dysfunction develops rapidly 2
• Do NOT proceed to intervention for secondary MR without first optimizing GDMT and considering CRT 2, 3
• Do NOT perform mitral valve replacement when repair is feasible - repair has superior outcomes 2
• Do NOT use TEER as first-line for primary MR in surgical candidates 2
• Do NOT use vasodilators in hypertrophic cardiomyopathy or mitral valve prolapse - they can worsen MR severity 5