What are the clinical treatment guidelines for severe annular mitral valve regurgitation?

Clinical Treatment Guidelines for Severe Annular Mitral Valve Regurgitation

Surgical intervention is the primary treatment for severe annular mitral valve regurgitation, with mitral valve repair preferred over replacement when feasible, particularly in primary mitral regurgitation. 1

Classification of Mitral Regurgitation

• Primary MR: Direct valve abnormality (leaflets and chordae structurally abnormal) 1
• Secondary MR: Results from LV geometry alterations with structurally normal valve components, commonly seen in dilated or ischemic cardiomyopathies and chronic atrial fibrillation with LA enlargement 1

Diagnostic Approach

• Echocardiography is essential for diagnosis, determining severity, etiology, and valve anatomy/function 1
• An integrative approach using multiple parameters is recommended for assessing MR severity rather than relying on a single measurement 1
• Different thresholds define severe MR based on etiology:
  • Primary MR: EROA ≥0.4 cm², regurgitant volume ≥60 ml 1
  • Secondary MR: EROA ≥0.2 cm², regurgitant volume ≥30 ml 1

Management of Primary Mitral Regurgitation

Surgical Intervention

• Symptomatic patients: Surgery is indicated for patients with severe MR who are symptomatic (NYHA class II-IV) with LVEF >30% 1
• Asymptomatic patients: Surgery is indicated when there is:
  • LV dysfunction (LVEF ≤60%) and/or LV end-systolic diameter ≥40 mm 1
  • New onset atrial fibrillation or pulmonary hypertension (SPAP >50 mmHg) 1
  • Significant left atrial dilatation (volume index ≥60 ml/m² or diameter >55 mm) with high likelihood of durable repair 1

Choice of Procedure

• Mitral valve repair is strongly preferred over replacement when anatomically feasible and durable repair is likely 1, 2
• Repair should be performed at centers with high surgical volume and expertise 1
• Chordal-sparing mitral valve replacement should be considered when repair is not feasible 1

Management of Secondary Mitral Regurgitation

Medical Therapy

• Optimize guideline-directed medical therapy for heart failure:
  • ACE inhibitors/ARBs
  • Beta-blockers
  • Mineralocorticoid receptor antagonists
  • Consider SGLT2 inhibitors and sacubitril/valsartan 1
• Cardiac resynchronization therapy (CRT) should be performed if indicated for heart failure 1
• Medical therapy should be optimized before determining severity of MR, as secondary MR is dynamic and may improve with treatment 1

Surgical Intervention

• Surgery is recommended for patients with severe secondary MR undergoing CABG with LVEF >30% 1
• Surgery may be considered in patients with severe secondary MR and LVEF >30% who remain symptomatic despite optimal medical management (including CRT if indicated) 1
• MV repair with undersized rigid annuloplasty ring is preferred for ischemic MR 1

Percutaneous Interventions

• Transcatheter edge-to-edge repair (TEER) should be considered in:
  • Symptomatic patients with severe primary MR at high/prohibitive surgical risk with favorable anatomy and life expectancy ≥1 year 1
  • Patients with severe secondary MR, LVEF >30%, persistent symptoms despite optimal medical therapy (including CRT if indicated), and no indication for coronary revascularization 1
• Heart team evaluation is essential to determine the most appropriate intervention 1

Surveillance for Asymptomatic Patients

• Severe MR: Clinical and echocardiographic follow-up every 6-12 months 1
• Consider exercise echocardiography, biomarkers, and novel measurements of LV function (e.g., global longitudinal strain) for risk stratification 1
• More frequent follow-up if LV dimensions are increasing or approaching thresholds for intervention 1

Special Considerations

• For acute severe MR: Vasodilator therapy (sodium nitroprusside or nicardipine), inotropic support if hemodynamically unstable, and mechanical support with intra-aortic balloon pump may be needed 1
• Risk assessment should include STS-PROM score, frailty evaluation, and assessment of comorbidities 1
• Patients with mechanical prosthetic valves require careful anticoagulation management perioperatively 1

Common Pitfalls to Avoid

• Delaying surgery until symptoms develop in patients with severe MR and evidence of LV dysfunction can lead to worse postoperative outcomes 1
• Failing to reassess MR severity after optimization of medical therapy in secondary MR can lead to unnecessary interventions 1
• Relying solely on a single echocardiographic parameter (like EROA) without an integrated approach can lead to misclassification of MR severity 1
• Not referring appropriate patients to centers with expertise in mitral valve repair may result in suboptimal outcomes 1, 2