What is the recommended treatment strategy for mitral regurgitation, including management of asymptomatic mild‑to‑moderate disease and indications for surgical repair, valve replacement, or transcatheter edge‑to‑edge repair?

Treatment of Mitral Regurgitation

For symptomatic severe primary mitral regurgitation, mitral valve surgery (preferably repair) is indicated when LVEF >30%, and for asymptomatic severe disease, surgery is recommended when LVEF ≤60% or left ventricular end-systolic diameter (LVESD) ≥40 mm. 1, 2

Management of Asymptomatic Mild-to-Moderate Disease

Mild Mitral Regurgitation

• No specific medical therapy is required for isolated mild MR with normal left ventricular function. 3
• Clinical evaluation every 6-12 months with annual echocardiography to monitor for progression. 3
• Monitor specifically for: progression of MR severity, development of symptoms, changes in LV size or function, and pulmonary artery pressure. 3
• Blood pressure control is essential as hypertension worsens MR severity. 3

Moderate Mitral Regurgitation

• Asymptomatic patients with preserved LV function require yearly clinical follow-up with echocardiography every 1-2 years. 1, 2
• More frequent reassessment (every 6 months) if LV dilation is occurring. 1, 2
• Beta-blockers appear to lessen MR, prevent deterioration of LV function, and improve survival in asymptomatic patients with moderate to severe primary MR. 4
• ACE inhibitors or ARBs reduce MR severity, especially in asymptomatic patients. 4

Critical caveat: In patients with hypertrophic cardiomyopathy or mitral valve prolapse, vasodilators can paradoxically increase MR severity and should be avoided. 4

Indications for Surgical Intervention

Symptomatic Severe Primary MR

• Surgery is indicated for all symptomatic patients with LVEF >30%. 1, 2
• For LVEF 20-30%, surgery may be considered if refractory to medical therapy with high likelihood of durable repair and low comorbidity. 2
• Transcatheter edge-to-edge repair (TEER) is reasonable for prohibitive surgical risk patients with favorable anatomy (LVEF 20-50%, LVESD ≤70 mm, pulmonary artery systolic pressure ≤70 mmHg). 1, 2

Asymptomatic Severe Primary MR

Surgery is indicated when:

• LVEF ≤60% and/or LVESD ≥40 mm (Class I indication). 1, 2
• New-onset atrial fibrillation secondary to MR. 1
• Pulmonary hypertension with pulmonary artery systolic pressure ≥50 mmHg. 1

Surgery should be considered when:

• LVEF >60% and LVESD <40 mm with >95% likelihood of successful repair, expected mortality <1%, and performed at an experienced heart valve center. 1, 2
• Significant left atrial dilatation (LA volume index ≥60 mL/m² or diameter >55 mm) when durable repair is likely at a heart valve center. 1
• Progressive increase in LV size or decrease in ejection fraction on ≥3 serial imaging studies. 1

Severe Secondary MR

• Optimize guideline-directed medical therapy (GDMT) first, including ACE inhibitors/ARBs, beta-blockers, mineralocorticoid receptor antagonists, and cardiac resynchronization therapy if indicated. 1, 5
• Valve surgery may be considered in symptomatic patients despite optimal GDMT. 1, 2
• TEER should be considered for symptomatic patients with LVEF >30%, persistent symptoms despite optimal medical therapy, and no indication for coronary revascularization. 2, 5
• MV surgery is recommended for patients with severe secondary MR undergoing CABG with LVEF >30%. 1, 2

Choice of Intervention: Repair vs. Replacement

Mitral valve repair is strongly preferred over replacement when technically feasible. 1, 2, 5

Primary MR

• Repair is recommended over replacement for posterior leaflet disease (Class I). 1
• Repair is recommended over replacement for anterior leaflet or bileaflet involvement when feasible. 1
• Surgery should be performed at experienced centers with repair rates ≥80-90% and operative mortality <1%. 2, 6
• These high-volume centers achieve approximately 70% reduction in mortality compared to medical management. 6

Secondary MR

• Repair with undersized rigid annuloplasty ring is preferred in selected patients without advanced LV remodeling. 2

Concomitant Cardiac Surgery

MV surgery is recommended for patients with severe primary MR undergoing cardiac surgery for other indications (Class I). 1, 2

• MV surgery is reasonable when severe MR is present and CABG is being performed. 1
• Some guidelines recommend MV surgery for moderate MR when undergoing concomitant CABG. 1

Surveillance Protocol

Severe MR

• Asymptomatic patients: follow-up every 6-12 months with echocardiography. 1, 2, 5
• Consider biomarkers (BNP) to guide optimal timing of intervention. 1, 5
• Exercise echocardiography, Holter monitoring, and CMR may be useful for risk stratification. 1, 2

Moderate MR

• Asymptomatic patients with preserved LV function: yearly clinical evaluation with echocardiography every 1-2 years. 1, 2
• More frequent reassessment if LV is dilating. 1, 2

Mild MR

• Clinical evaluation every 3-5 years. 1

Acute Severe MR

Urgent surgery is indicated for acute severe MR. 2, 5

• Stabilization includes vasodilator therapy and inotropic support if hemodynamically unstable. 5
• Mechanical support with intra-aortic balloon pump may be needed. 5

Critical Pitfalls to Avoid

• Do not delay referral to experienced mitral valve centers where repair rates are high (≥80-90%) and outcomes are superior. 2, 6
• Do not use vasodilators in patients with mitral valve prolapse or hypertrophic cardiomyopathy as they can worsen MR. 4
• Do not wait for symptoms to develop in asymptomatic patients with LV dysfunction (LVEF ≤60% or LVESD ≥40 mm)—surgery is indicated. 1, 2
• Do not rely solely on LVEF; LVESD ≥40 mm is an independent indication for surgery even with preserved ejection fraction. 1, 2
• Mitral annular diameter >39.6 mm predicts progression from moderate to severe MR in asymptomatic mitral valve prolapse patients and warrants closer monitoring. 7