What is the recommended treatment for severe mitral regurgitation?

Treatment of Severe Mitral Regurgitation

For severe mitral regurgitation, surgical mitral valve repair is the definitive treatment of choice for both symptomatic patients and asymptomatic patients with left ventricular dysfunction (LVEF ≤60% or LVESD ≥40 mm), with repair strongly preferred over replacement to reduce mortality by approximately 70%. 1, 2

Initial Classification: Primary vs Secondary MR

The first critical step is determining whether MR is primary (degenerative valve disease) or secondary (functional, due to LV dysfunction), as this completely changes the management algorithm. 1, 2

• Primary MR involves structural valve abnormalities (prolapse, flail leaflet, chordal rupture) 1
• Secondary MR results from LV dysfunction with structurally normal leaflets 3
• Transthoracic echocardiography is the fundamental diagnostic tool to make this distinction 3

Diagnostic Thresholds for Severe MR

Severe MR requires integration of multiple echocardiographic parameters: 3

• Vena contracta ≥7 mm
• EROA ≥0.4 cm² (primary MR) or ≥0.3 cm² (secondary MR if elliptical orifice) 1, 2
• Regurgitant fraction ≥50%
• Regurgitant volume ≥60 mL/beat (primary) or ≥30 mL/beat (secondary) 3
• Pulmonary vein systolic flow reversal 3

Management Algorithm for Primary (Degenerative) MR

Symptomatic Patients

Surgery is indicated for ALL symptomatic patients with severe primary MR, regardless of left ventricular function. 3, 1, 4 This is a Class I recommendation across all major guidelines.

Asymptomatic Patients

Surgery is indicated when ANY of the following are present: 3, 4

• LVEF ≤60% (not the traditional 50% threshold—intervene earlier)
• LVESD ≥40 mm
• New-onset atrial fibrillation 3
• Pulmonary artery systolic pressure >50 mmHg 3

Critical pitfall: Do not wait until LVEF drops below 50% or symptoms develop—by then, irreversible LV remodeling may have occurred. The 60% LVEF threshold represents early dysfunction and is the trigger for intervention. 2

Surgical Technique Preference

• Mitral valve repair is strongly preferred over replacement when anatomically feasible, reducing mortality by approximately 70% compared to medical management 2, 5
• Repair rates exceeding 95-99% are achievable at experienced centers, even with complex lesions including anterior leaflet or bileaflet prolapse 6
• Surgery should be performed at a heart valve center with high repair rates (>80-90%) and low operative mortality (<1%) 3, 1, 5
• Chordal-sparing techniques should be used if replacement is necessary 3

Role of Transcatheter Edge-to-Edge Repair (TEER) in Primary MR

TEER with MitraClip is reserved ONLY for high or prohibitive surgical risk patients with suitable valve morphology. 3, 4, 2 Both American and European guidelines agree this is NOT first-line therapy for surgical candidates.

• TEER may be considered (Class IIa-IIb) when surgical risk is prohibitive and anatomy is favorable 3, 4
• The EVEREST II trial demonstrated TEER was safer but less effective than surgery 7
• Do not use TEER as first-line therapy in surgical candidates—this is a common pitfall 2

Management Algorithm for Secondary (Functional) MR

First-Line: Optimize Medical Therapy

Guideline-directed medical therapy (GDMT) is mandatory as the first step before considering any intervention. 3, 1, 4, 2 This cannot be bypassed.

GDMT includes: 1, 2

• ACE inhibitors/ARBs or sacubitril/valsartan
• Beta-blockers
• Mineralocorticoid receptor antagonists (spironolactone/eplerenone)
• SGLT2 inhibitors in appropriate patients
• Diuretics for fluid overload 1, 2
• Nitrates for acute dyspnea with dynamic MR component 1, 2

Cardiac Resynchronization Therapy (CRT)

CRT should be implemented in patients meeting guideline criteria (LVEF ≤35%, QRS ≥150 ms, LBBB), as it may reduce MR severity through improved papillary muscle synchronization. 1, 2

Surgical Intervention for Secondary MR

Surgery is indicated when: 3

• Patient is undergoing CABG AND has LVEF >30% (Class I recommendation) 3, 1, 2
• Patient remains symptomatic despite optimal GDMT and has low surgical risk (Class IIb) 3

Important nuance: There is no conclusive evidence that mitral valve intervention improves survival in secondary MR, as the underlying problem is LV dysfunction, not the valve itself. 3 The valve is a "victim," not the culprit.

Transcatheter Edge-to-Edge Repair (TEER) for Secondary MR

TEER should be considered (Class IIa-IIb) for patients with: 3, 2

• Severe secondary MR with EROA ≥0.3 cm²
• LVEF 20-50%
• LVESD ≤70 mm
• Persistent NYHA class II-IV symptoms despite optimal GDMT (including CRT if indicated)
• Appropriate anatomy (favorable for TEER)
• Systolic pulmonary artery pressure ≤70 mmHg 3

Critical pitfall: Do not proceed to TEER without first optimizing GDMT and considering CRT eligibility. 2

Surveillance and Follow-up

Severe MR (Asymptomatic)

• Clinical and echocardiographic evaluation every 6-12 months 1, 4, 2
• Consider BNP monitoring to guide timing of intervention 1, 2

Moderate MR

• Clinical evaluation every 6-12 months with annual echocardiography 4, 2

Mild MR

• Monitor every 3-5 years 1, 2

Additional Diagnostic Considerations

When TTE is Inadequate

• Transesophageal echocardiography (TOE) is indicated when TTE is non-diagnostic, for pre-surgical planning, intraoperative imaging, and post-intervention assessment 3
• Cardiac MRI should be used when echocardiographic measurements are ambiguous, particularly for quantifying LV/RV function and MR severity 1, 2

Exercise Testing

• Exercise echocardiography or stress testing should be performed in asymptomatic patients to unmask symptoms or assess dynamic worsening of MR 3, 1

Invasive Catheterization

• Recommended when discordance exists between non-invasive imaging modalities, especially when discrepancies would trigger intervention 3

Multidisciplinary Heart Team Approach

All intervention decisions should involve multidisciplinary team discussion, considering: 1, 2

• Valve morphology and MR etiology
• Patient comorbidities and frailty
• Surgical risk (STS-PROM score)
• Organ system compromise
• Procedure-specific impediments 1

The heart team should include cardiac surgeons, interventional cardiologists, imaging specialists, and heart failure cardiologists. 2