What is the workup and management of severe mitral regurgitation?

Workup and Management of Severe Mitral Regurgitation

Severe mitral regurgitation requires a comprehensive diagnostic workup followed by either surgical or transcatheter intervention based on etiology, symptoms, and left ventricular function.

Diagnostic Workup

Echocardiography

• Transthoracic echocardiography (TTE) is the cornerstone of diagnosis 1

  • Integrative approach using multiple parameters to assess severity:
    • Vena contracta width ≥7 mm
    • Effective regurgitant orifice area (EROA) ≥0.4 cm² for primary MR, ≥0.2 cm² for secondary MR
    • Regurgitant volume ≥60 mL/beat for primary MR, ≥30 mL/beat for secondary MR
    • Regurgitant fraction ≥50%
    • Pulmonary vein systolic flow reversal
    • Dense triangular CW Doppler profile

• Transesophageal echocardiography (TEE) 1

  • Indicated when TTE is non-diagnostic
  • Essential for pre-surgical planning
  • Provides detailed valve morphology assessment
  • Required for evaluating suitability for transcatheter repair

Additional Testing

• Exercise testing/stress echocardiography 1

  • Unmasks symptoms in apparently asymptomatic patients
  • Evaluates dynamic nature of MR during exertion
  • Assesses exercise capacity and pulmonary pressures

• Cardiac MRI 1

  • When echocardiographic findings are inconclusive
  • Provides accurate assessment of regurgitant volume and fraction
  • Evaluates ventricular size and function

• Cardiac catheterization 1

  • When non-invasive imaging is discordant
  • Evaluates coronary anatomy prior to surgical intervention
  • Measures hemodynamics when clinical and imaging data are inconsistent

Management Algorithm

Primary (Degenerative) Mitral Regurgitation

1. Symptomatic patients with severe MR

   • Surgical intervention is indicated (Class I) 1
   • Mitral valve repair is preferred over replacement when feasible 1

2. Asymptomatic patients with severe MR

   • Surgical intervention is indicated when:
     • LV dysfunction (LVEF ≤60%) is present 1
     • LV dilation (LVESD ≥40 mm) is present 1
     • New-onset atrial fibrillation occurs 1
     • Pulmonary hypertension (PASP >50 mmHg) develops 1
   • Consider early surgery in asymptomatic patients with preserved LV function if:
     • High likelihood of successful repair (>95%) at an experienced center 1
     • Low surgical risk 1

3. Medical therapy

   • Limited role in primary MR 2
   • Beta-blockers may be beneficial in asymptomatic patients with moderate-severe MR 2
   • Regular clinical follow-up every 6-12 months 1
   • Echocardiographic evaluation every 6-12 months 1

Secondary (Functional) Mitral Regurgitation

1. Optimize guideline-directed medical therapy (GDMT) 1, 3

   • Heart failure medications (ACE inhibitors/ARBs, beta-blockers, MRAs)
   • Diuretics for symptom relief
   • Reassess MR severity after optimization (may reduce severity in 40-45% of patients) 3

2. Cardiac resynchronization therapy (CRT) 1, 3

   • For patients meeting criteria for CRT
   • May reduce MR severity through improved coordination of papillary muscle function

3. Surgical intervention

   • Indicated for severe secondary MR in patients undergoing CABG with LVEF >30% (Class I) 1
   • Consider in patients with severe MR and LVEF >30% who remain symptomatic despite optimal medical management (Class IIb) 1
   • Mitral valve repair preferred, but replacement may be necessary with unfavorable morphology 1

4. Transcatheter edge-to-edge repair (TEER) 1, 3

   • Consider in symptomatic patients with severe secondary MR despite optimal medical therapy who have:
     • High surgical risk
     • Suitable valve anatomy for the procedure
     • LVEF between 20-50%
   • Number needed to treat: 3.1 to reduce heart failure hospitalization and 5.9 to reduce all-cause death 3

Acute Severe Mitral Regurgitation

1. Immediate stabilization 4

   • Afterload reduction (nitroprusside, nitroglycerin)
   • Inotropic support if needed
   • Mechanical circulatory support in cardiogenic shock

2. Urgent surgical intervention 4

   • Mitral valve repair when feasible
   • Valve replacement when repair not possible

Special Considerations

Dynamic Nature of MR

• MR severity can change with loading conditions 1
• Always reassess after optimization of medical therapy 1
• Consider exercise echocardiography to evaluate dynamic changes 1

Monitoring Recommendations

• Asymptomatic severe MR: clinical evaluation every 6 months, echocardiography every 6-12 months 1
• Moderate MR: clinical evaluation annually, echocardiography every 1-2 years 1

Common Pitfalls

• Color Doppler can overestimate MR severity with high blood pressure or high LV systolic pressure 1
• Color Doppler can underestimate MR with high LA pressures or low LVEF 1
• Single measurements may be misleading; always use an integrative approach 1
• Failure to optimize medical therapy before determining need for intervention in secondary MR 1, 3
• Delaying referral for intervention until irreversible LV dysfunction develops 5, 6

By following this structured approach to diagnosis and management, patients with severe mitral regurgitation can receive timely and appropriate interventions to improve symptoms, prevent heart failure, and enhance survival.