When is surgical intervention recommended for patients with secondary severe mitral regurgitation (MR)?

Surgical Intervention for Secondary Severe Mitral Regurgitation

Surgical intervention for secondary severe mitral regurgitation is indicated in patients with LVEF >30% who remain symptomatic despite optimal medical therapy, and is strongly recommended when patients are undergoing CABG. 1

Diagnostic Assessment

• Echocardiography is essential for:

  • Confirming severity of MR (integrative approach)
  • Assessing valve anatomy and function
  • Evaluating LV size and function
  • Measuring pulmonary artery pressure
  • Assessing right ventricular function

• Severity thresholds for secondary MR are lower than primary MR:

  • EROA ≥20 mm² (vs. 40 mm² in primary MR)
  • Regurgitant volume ≥30 mL (vs. 60 mL in primary MR) 1

• Dynamic assessment:

  • Exercise echocardiography may help identify patients who would benefit from combined surgery 1
  • Reassessment after optimized medical therapy is crucial 1

Treatment Algorithm

Step 1: Optimize Medical Therapy

• Implement guideline-directed medical therapy (GDMT) for heart failure:
  • ACE inhibitors/ARBs
  • Beta-blockers
  • Mineralocorticoid receptor antagonists
  • SGLT2 inhibitors
  • Sacubitril/valsartan 2
• Consider cardiac resynchronization therapy (CRT) if indicated 2, 3
• Pursue sinus rhythm in patients with atrial fibrillation 3

Step 2: Surgical Intervention Decision Points

Class I Indications (Strong Recommendation):

• Severe secondary MR in patients undergoing CABG with LVEF >30% 1

Class IIa Considerations (Should be considered):

• Severe secondary MR with LVEF >30% who remain symptomatic despite optimal medical management (including CRT if indicated) with low surgical risk 1, 2

Class IIb Considerations (May be considered):

• Symptomatic patients with severe secondary MR despite optimal GDMT (including CRT) judged appropriate for surgery by heart team 1
• Transcatheter edge-to-edge repair (TEER) for high surgical risk patients with appropriate anatomy (LVEF 20-50%, LVESD ≤70 mm, PASP ≤70 mmHg) 1, 2

Surgical Approach Selection

• Mitral valve repair is preferred when feasible 1
• Mitral valve replacement should be considered in patients with unfavorable morphological characteristics 1
• Outcomes depend heavily on surgeon experience and center volume 1
• Heart team evaluation is crucial for determining optimal approach 2

Important Considerations and Pitfalls

• There is no conclusive evidence for survival benefit after mitral valve intervention in secondary MR 1
• Inadequate assessment of MR severity can lead to incorrect treatment decisions 2
• Failure to optimize medical therapy before considering intervention leads to suboptimal outcomes 2, 3
• Delaying intervention until severe LV dysfunction develops may result in poor outcomes 2
• Transcatheter edge-to-edge repair is underutilized in many countries despite showing benefit in carefully selected patients (NNT of 3.1 to reduce heart failure hospitalization) 3

Follow-up After Intervention

• Regular echocardiographic assessment (every 6-12 months)
• Continued optimization of medical therapy
• Monitoring for recurrent MR or progression of heart failure 1

The decision for surgical intervention in secondary severe MR requires careful assessment of symptoms, LV function, and response to medical therapy. While surgery is clearly indicated when patients are undergoing CABG, the benefit of isolated mitral valve surgery for secondary MR remains controversial and should be reserved for patients who remain symptomatic despite optimal medical therapy and have preserved LV function.