What is the management of mitral regurgitation?

Management of Mitral Regurgitation

Critical First Step: Distinguish Primary from Secondary MR

The single most important decision in managing mitral regurgitation is determining whether it is primary (degenerative valve disease) or secondary (functional due to left ventricular disease), as this completely changes the treatment algorithm. 1, 2, 3

• Transthoracic echocardiography is the fundamental diagnostic tool to make this distinction and assess severity 4
• Transesophageal echocardiography should be used when TTE is non-diagnostic, for pre-surgical planning, and intraoperative imaging 4
• Cardiovascular magnetic resonance (CMR) is indicated when echocardiographic measurements are ambiguous or uncertain 1, 2, 3

Defining Severe MR

Severe primary MR requires meeting these thresholds:

• Vena contracta ≥7 mm 4, 1, 2, 3
• Effective regurgitant orifice area (EROA) ≥0.4 cm² 4, 1, 2, 3
• Regurgitant fraction ≥50% 4, 1, 2
• Regurgitant volume ≥60 mL/beat 4, 1, 2, 3

Severe secondary MR has lower thresholds:

• EROA ≥0.3 cm² if the regurgitant orifice is elliptical 1, 2, 3

Management Algorithm for Primary (Degenerative) MR

Symptomatic Patients

All symptomatic patients with severe primary MR require surgical intervention regardless of left ventricular function. 1, 2, 3

• Mitral valve repair is strongly preferred over replacement when anatomically feasible, reducing mortality by approximately 70% 1
• Surgery must be performed at high-volume heart valve centers with repair rates >90% for isolated posterior leaflet prolapse and operative mortality <1% 1, 3
• Transcatheter edge-to-edge repair (TEER) is reserved ONLY for patients with prohibitive surgical risk and suitable valve morphology 1

Asymptomatic Patients

Surgery is indicated when any of the following develop: 1, 2

• LVEF ≤60% 1, 2
• LV end-systolic diameter ≥40 mm 1, 2
• New-onset atrial fibrillation 4, 2
• Pulmonary artery systolic pressure >50 mmHg 4, 2

Critical pitfall: Do not delay surgery once LVEF falls to ≤60% or LVESD reaches ≥40 mm, as irreversible left ventricular dysfunction develops rapidly. 1

Limited Role for Medical Therapy in Primary MR

• Beta-blockers may lessen MR severity, prevent deterioration of left ventricular function, and improve survival in asymptomatic patients with moderate to severe primary MR 5
• ACE inhibitors and ARBs reduce MR severity, especially in asymptomatic patients 5
• However, vasodilators can paradoxically increase MR severity in mitral valve prolapse and should be avoided 5

Management Algorithm for Secondary (Functional) MR

Step 1: Optimize Guideline-Directed Medical Therapy (GDMT)

GDMT is the mandatory first-line treatment and must be maximized before considering any intervention. 1, 2, 3, 6

Specific medications to implement:

• ACE inhibitors or ARBs as first-line therapy 1, 3

• Beta-blockers to prevent left ventricular deterioration 1, 3

• Mineralocorticoid receptor antagonists (aldosterone antagonists) 1, 2, 3

• Diuretics for fluid overload manifestations such as lower extremity edema 1, 2, 3

• Nitrates for acute dyspnea in patients with a large dynamic component of MR 1, 2, 3

• Rapid medication titration protocols reduce heart failure hospitalization and facilitate earlier referral for device therapy 6

• GDMT reduces MR severity in 40-45% of patients 6

Step 2: Pursue Sinus Rhythm and Consider CRT

Cardiac resynchronization therapy (CRT) should be implemented in patients meeting guideline criteria (typically LVEF ≤35%, QRS ≥150 ms, LBBB). 1, 3, 6

• CRT reduces MR severity through increased closing force and resynchronization of papillary muscles 2
• Pursuit of sinus rhythm in patients with atrial fibrillation significantly reduces MR severity 6

Step 3: Consider Transcatheter Edge-to-Edge Repair (TEER)

TEER should be considered for patients with severe secondary MR, LVEF 20-50%, persistent NYHA class II-IV symptoms despite optimal medical therapy and CRT when indicated. 1, 3, 6

• Number needed to treat is 3.1 to reduce heart failure hospitalization and 5.9 to reduce all-cause death 6
• Favorable anatomy includes flail posterior middle scallop, diastolic mitral area >4.0 cm², and absence of severe mitral annular calcification 1

Step 4: Surgical Intervention

Surgery is indicated when severe secondary MR is present and the patient is undergoing coronary artery bypass grafting (CABG) with LVEF >30%. 1, 2, 3

• Mitral valve surgery (repair or replacement) is reasonable if the patient remains symptomatic despite optimal GDMT 4

Critical pitfall: Do not proceed to intervention for secondary MR without first optimizing GDMT and considering CRT. 1

Surveillance and Follow-up Intervals

Asymptomatic severe MR:

• Clinical and echocardiographic follow-up every 6-12 months 1, 2, 3
• Serum biomarkers (BNP) may help guide optimal timing of intervention 1, 2

Moderate MR:

• Clinical evaluation every 6-12 months with annual echocardiography 1, 2, 3

Mild MR:

• Monitor every 3-5 years 1, 2, 3

Exercise Testing for Unmasking Symptoms

Exercise tolerance testing or stress echocardiography should be performed in asymptomatic patients to unmask potential symptoms and assess dynamic worsening of MR. 4, 1, 2

Mandatory Multidisciplinary Heart Team Approach

All intervention decisions must involve multidisciplinary team discussion by the heart team. 1, 2, 3

• The heart team must consider valve morphology, MR etiology, patient comorbidities, surgical risk, frailty, organ system compromise, and procedure-specific impediments 1, 2, 3
• Input from a cardiologist with experience managing heart failure is essential for secondary MR decisions 1, 3

Critical Pitfalls to Avoid

• Do not perform mitral valve replacement when repair is feasible 1
• Do not use TEER as first-line therapy for primary MR in surgical candidates 1
• Do not delay surgery in asymptomatic primary MR once LVEF falls to ≤60% or LVESD reaches ≥40 mm 1
• Do not proceed to intervention for secondary MR without first optimizing GDMT and considering CRT 1