Clinical Management of Severe Mitral Regurgitation

Initial Assessment and Classification

The European Society of Cardiology recommends that echocardiography is essential to determine whether mitral regurgitation is primary or secondary, guiding subsequent management decisions 2
Severe MR is defined by vena contracta ≥7 mm, effective regurgitant orifice area (EROA) ≥0.4 cm² for primary MR, regurgitant fraction (RF) ≥50%, and regurgitant volume (RVol) ≥60 mL/beat 3
For secondary MR, thresholds may differ with EROA ≥0.3 cm² if the regurgitant orifice is elliptical in nature 1
Exercise echocardiography should be considered when exercise-induced symptoms are present to assess for dynamic worsening of MR, as recommended by the European Heart Journal 2
Cardiovascular magnetic resonance (CMR) can be used to quantify LV/RV function, chamber size, and MR severity when echocardiographic measurements are ambiguous, according to the European Heart Journal 1

The American College of Cardiology recommends diuretics as first-line therapy for patients with fluid overload manifestations such as lower extremity edema 2
Guideline-directed medical therapy (GDMT) including ACE inhibitors, beta-blockers, and aldosterone antagonists is mandatory as the first step for all patients with secondary MR, as stated by the European Society of Cardiology 2
Nitrates may be useful for treating acute dyspnea in patients with a large dynamic component of MR, according to the European Heart Journal 2

The European Society of Cardiology indicates that surgery is indicated for symptomatic patients with severe primary MR, regardless of left ventricular function 1, 2
Mitral valve repair is strongly preferred over replacement when technically feasible, as recommended by the American College of Cardiology 2
For asymptomatic severe primary MR, surgical intervention is indicated when LVEF ≤60% and/or LV end-systolic dimension (LVESD) ≥40 mm, or new-onset atrial fibrillation or pulmonary artery systolic pressure >50 mmHg, according to the European Heart Journal 3

The European Society of Cardiology recommends that optimal medical therapy must be maximized before considering interventional approaches 2
Cardiac resynchronization therapy (CRT) should be considered in appropriate candidates as it may reduce MR severity through increased closing force and resynchronization of papillary muscles, as stated by the American College of Cardiology 2
Surgery is indicated in patients with severe secondary MR undergoing coronary artery bypass grafting and LVEF >30%, according to the European Heart Journal 2

The European Society of Cardiology recommends that asymptomatic severe MR requires follow-up every 6 to 12 months 1, 2
Patients with moderate MR should have clinical evaluation every 6-12 months with annual echocardiography, as recommended by the American College of Cardiology 2
Patients with mild MR should be monitored every 3-5 years, according to the European Heart Journal 4
Serum biomarkers (e.g., BNP) may be helpful to guide optimal timing of intervention in asymptomatic patients with severe MR, as stated by the European Heart Journal 1

The European Society of Cardiology strongly emphasizes multidisciplinary team (MDT) discussion by the heart team to guide optimal intervention 1
The heart team should consider the morphology of the mitral valve, MR etiology, patient comorbidities, and surgical risk, as recommended by the American College of Cardiology 1
Preoperative risk stratification should include assessment of STS-PROM score, frailty, organ system compromise, and procedure-specific impediments, according to the European Heart Journal 5