What are the clinical treatment guidelines for severe mitral regurgitation?

Clinical Treatment Guidelines for Severe Mitral Regurgitation

The management of severe mitral regurgitation requires a multidisciplinary team approach with treatment decisions based on whether the MR is primary (valve abnormality) or secondary (due to left ventricular dysfunction), patient symptoms, and cardiac function parameters. 1, 2

Classification and Diagnosis

• Echocardiography is essential for determining MR etiology (primary vs. secondary), severity, and valve anatomy/function 2
• Severe MR is defined by vena contracta ≥7 mm, effective regurgitant orifice area (EROA) ≥0.4 cm² for primary MR, regurgitant fraction ≥50%, and regurgitant volume ≥60 mL/beat 3
• For secondary MR, thresholds may differ with EROA ≥0.3 cm² if the regurgitant orifice is elliptical in nature 1
• Cardiovascular magnetic resonance (CMR) should be used when echocardiographic measurements are ambiguous 1
• Exercise echocardiography should be considered for patients with exercise-induced symptoms to assess dynamic worsening of MR 3

Management of Primary Mitral Regurgitation

Surgical Intervention

• Surgery is indicated for symptomatic patients with severe primary MR regardless of left ventricular function 2, 3
• Surgery is indicated for asymptomatic patients with severe primary MR when:
  • LVEF ≤60% and/or LV end-systolic diameter ≥40 mm 2, 3
  • New-onset atrial fibrillation or pulmonary artery systolic pressure >50 mmHg 3
  • Progressive increase in LV size or decrease in EF on ≥3 serial imaging studies 1
• Mitral valve repair is strongly preferred over replacement when technically feasible 2, 3
• Surgery should be performed in a heart valve center with high repair rates (≥80-90%) 1

Percutaneous Interventions

• Transcatheter edge-to-edge repair (TEER) should be considered for symptomatic patients with severe primary MR at high/prohibitive surgical risk with favorable anatomy and life expectancy ≥1 year 2, 4

Management of Secondary Mitral Regurgitation

Medical Therapy

• Guideline-directed medical therapy (GDMT) is mandatory as the first step for all patients with secondary MR 3, 5
• GDMT includes:
  • ACE inhibitors/ARBs, beta-blockers, and mineralocorticoid receptor antagonists 2, 3
  • SGLT2 inhibitors and sacubitril/valsartan 2, 5
  • Diuretics for fluid overload manifestations 3
• Cardiac resynchronization therapy (CRT) should be considered in appropriate candidates as it may reduce MR severity 3, 5
• Management of atrial fibrillation and pursuit of sinus rhythm can significantly reduce MR severity 5

Surgical and Percutaneous Interventions

• Surgery is indicated in patients with severe secondary MR undergoing coronary artery bypass grafting with LVEF >30% 2, 3
• TEER should be considered for patients with severe secondary MR, LVEF >30%, persistent symptoms despite optimal medical therapy, and no indication for coronary revascularization 2, 1
• For patients with severe secondary MR who remain symptomatic despite GDMT and CRT (if indicated), TEER has been shown to reduce heart failure hospitalizations and mortality 5

Surveillance and Follow-up

• Asymptomatic patients with severe MR require clinical and echocardiographic follow-up every 6-12 months 2, 3
• Patients with moderate MR should have clinical evaluation every 6-12 months with annual echocardiography 3
• Patients with mild MR should be monitored every 3-5 years 3
• Serum biomarkers (e.g., BNP) may help guide optimal timing of intervention in asymptomatic patients with severe MR 1, 3

Special Considerations

• For acute severe MR, management includes vasodilator therapy, inotropic support if hemodynamically unstable, and mechanical support with intra-aortic balloon pump if needed 2, 1
• Risk stratification should include assessment of STS-PROM score, frailty, organ system compromise, and procedure-specific impediments 3
• Early surgical intervention may be considered in asymptomatic patients with severe MR when there is a high likelihood of successful repair and low operative risk (<1%) 6, 7

Pitfalls and Caveats

• Vasodilators can increase the severity of MR in the setting of hypertrophic cardiomyopathy or mitral valve prolapse 8
• Delaying intervention until symptoms develop or LV dysfunction occurs may result in irreversible myocardial damage and worse outcomes 6, 7
• Underuse of TEER for appropriate candidates may lead to increased morbidity and mortality 5
• Relying on a single echocardiographic parameter for assessing MR severity may lead to misclassification; an integrative approach using multiple parameters is recommended 2