What is the guideline for managing severe mitral regurgitation?

Management of Severe Mitral Regurgitation

The management of severe mitral regurgitation should prioritize optimizing guideline-directed medical therapy first, followed by surgical intervention for primary MR when symptomatic or when specific criteria are met, while secondary MR requires a more nuanced approach with consideration of underlying cardiac pathology. 1, 2

Classification and Diagnosis

Primary vs. Secondary MR

• Primary MR: Structural abnormality of the valve apparatus itself
• Secondary MR: Normal valve structure with dysfunction due to LV remodeling (dilated or ischemic cardiomyopathy)

Diagnostic Assessment

• Echocardiography: Essential first-line tool for diagnosis and severity assessment 2
• Quantitative parameters for severe MR:
  • Primary MR: EROA ≥0.4 cm², regurgitant volume ≥60 mL/beat
  • Secondary MR: EROA ≥0.3-0.4 cm² (ESC) or ≥0.2 cm² (ATTS), regurgitant volume ≥45-60 mL/beat 1
• Integrated approach: Multiple parameters should be used rather than relying on a single measurement 1, 2

Management Algorithm for Primary MR

Asymptomatic Patients with Preserved LV Function

• Regular monitoring every 6-12 months with echocardiography 2
• Surgery indicated when:
  • LVEF ≤60% or LVESD ≥45 mm (Class I recommendation) 1
  • New-onset atrial fibrillation or pulmonary hypertension (SPAP >50 mmHg at rest) 1
  • High likelihood of durable repair with flail leaflet and LVESD ≥40 mm 1
  • Consider surgery if left atrial dilatation (volume index ≥60 ml/m²) in sinus rhythm or pulmonary hypertension on exercise (SPAP ≥60 mmHg) 1

Symptomatic Patients

• Surgery indicated (Class I recommendation) with preference for mitral valve repair over replacement when feasible 1, 2
• Early surgery (within 2 months of symptom onset) is associated with better outcomes 1

Management Algorithm for Secondary MR

Initial Approach

• Optimize guideline-directed medical therapy for heart failure (ACE inhibitors/ARBs, beta-blockers, MRAs, SGLT2 inhibitors) 1, 2
• Consider cardiac resynchronization therapy (CRT) if indicated 1
• Reassess MR severity after optimization of medical therapy due to its dynamic nature 1

Persistent Severe Secondary MR Despite Optimal Medical Therapy

• Surgery indicated in patients undergoing CABG with LVEF >30% (Class I recommendation) 1
• Surgery may be considered in symptomatic patients with LVEF >30% and low surgical risk 1
• Transcatheter edge-to-edge repair (TEER) may be considered in patients at high surgical risk with suitable anatomy and life expectancy >1 year 1

Special Considerations

Dynamic Nature of Secondary MR

• MR severity can change significantly with loading conditions and medical therapy 1
• Do not label patients as having severe MR until they are on optimal medical therapy 1

Surgical Approach

• Mitral valve repair is preferred when feasible, particularly for primary MR 1
• Mitral valve replacement should be considered in patients with unfavorable morphological characteristics 1
• Outcomes depend significantly on surgeon experience and center volume 1

Transcatheter Interventions

• TEER has shown reduced 24-month mortality compared to medical therapy in selected patients with secondary MR 3
• Inclusion criteria for TEER in secondary MR:
  • Symptomatic heart failure (NYHA II-IV) despite optimal GDMT
  • LVEF 20-50%
  • LV end-systolic diameter ≤70 mm
  • Suitable valve anatomy 1

Common Pitfalls to Avoid

• Underestimating MR severity by relying solely on color jet area 2
• Failing to distinguish between primary and secondary MR, which have different management approaches 2
• Inadequate medical optimization before considering intervention for secondary MR 1, 2
• Not recognizing the dynamic nature of secondary MR, which can improve with medical therapy 1
• Delaying referral to comprehensive valve centers for complex cases 2

By following these guidelines and considering the specific etiology and severity of MR, clinicians can optimize outcomes for patients with severe mitral regurgitation.