What is the management approach for mitral regurgitation?

Management of Mitral Regurgitation

The management of mitral regurgitation fundamentally depends on whether it is primary (valve disease) or secondary (left ventricular disease), with primary MR requiring surgical repair as first-line therapy in symptomatic patients or when specific LV thresholds are met, while secondary MR mandates optimization of guideline-directed medical therapy before considering any intervention. 1, 2

Initial Classification and Diagnostic Assessment

Echocardiography is mandatory to distinguish primary from secondary MR, as this classification completely determines the management pathway. 1, 2

Severity Criteria

• Severe primary MR: vena contracta ≥7 mm, EROA ≥0.4 cm², regurgitant fraction ≥50%, regurgitant volume ≥60 mL/beat 1, 2
• Severe secondary MR: EROA ≥0.3 cm² if the regurgitant orifice is elliptical in nature 3, 1
• Use cardiovascular magnetic resonance (CMR) when echocardiographic measurements are ambiguous or uncertain to quantify LV/RV function, chamber size, and MR severity 3, 1

Functional Assessment

• Perform exercise echocardiography in patients reporting exercise-induced symptoms to detect dynamic worsening of MR, elevated pulmonary artery pressures, or failure of LV systolic function to augment normally 3, 1
• Measure serum BNP levels to help guide timing of intervention in asymptomatic patients with severe MR 3, 1

Management Algorithm for Primary (Degenerative) MR

Symptomatic Severe Primary MR

Surgery is indicated for all symptomatic patients with severe primary MR, regardless of left ventricular ejection fraction. 3, 1, 2

• Mitral valve repair is strongly preferred over replacement when anatomically feasible, as it provides superior outcomes 3, 2
• Surgery should be performed at high-volume centers with documented high repair rates (>90% for isolated posterior leaflet prolapse) and operative mortality <1% 3

Asymptomatic Severe Primary MR

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

• LVEF ≤60%
• LV end-systolic diameter (LVESD) ≥40 mm
• New-onset atrial fibrillation
• Pulmonary artery systolic pressure >50 mmHg

Critical pitfall: Do not delay surgery once LVEF falls to ≤60% or LVESD reaches ≥40 mm, as waiting for further deterioration worsens postoperative outcomes. 2

Transcatheter Edge-to-Edge Repair (TEER) for Primary MR

• TEER is reserved only for patients with prohibitive surgical risk and suitable valve anatomy 2
• Do not use TEER as first-line therapy in surgical candidates with primary MR 2

Management Algorithm for Secondary (Functional) MR

Step 1: Optimize Medical Therapy (Mandatory First Step)

Guideline-directed medical therapy (GDMT) must be maximized before considering any intervention. 1, 2

• ACE inhibitors or ARBs as first-line therapy 1, 2
• Beta-blockers to prevent LV deterioration 1, 2
• Mineralocorticoid receptor antagonists (aldosterone antagonists) 1, 2
• Diuretics for fluid overload manifestations such as lower extremity edema 1, 2
• Nitrates may be useful for acute dyspnea in patients with a large dynamic component of MR 1

Step 2: Cardiac Resynchronization Therapy (CRT)

Implement CRT in patients who meet guideline-directed criteria (typically LVEF ≤35%, QRS ≥150 ms, LBBB), as it may reduce MR severity through increased closing force and resynchronization of papillary muscles. 1, 2

Step 3: Interventional Therapy (Only After Steps 1 and 2)

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
• For isolated severe secondary MR: Surgery can be considered for selected patients with advanced NYHA class III-IV symptoms despite optimal GDMT including CRT 3
• Chordal-sparing mitral valve replacement is preferred over downsized annuloplasty repair in severely symptomatic patients with severe ischemic secondary MR, as repair has higher rates of recurrent MR 3

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 3, 2
• Ensure appropriate patient selection: The divergent results from COAPT and MITRA-FR trials highlight that patient selection is critical, with better outcomes in patients with proportionate MR relative to LV size 3

Critical pitfall: Do not proceed to intervention for secondary MR without first optimizing GDMT and considering CRT, as many patients improve with medical therapy alone. 2

Surveillance and Follow-up Intervals

• Asymptomatic severe MR: Clinical and echocardiographic follow-up every 6-12 months 3, 1, 2
• Moderate MR: Clinical evaluation every 6-12 months with annual echocardiography 1, 2
• Mild MR: Monitor every 3-5 years 1, 2
• Serial BNP measurements may help identify patients at higher risk of deterioration 1

Multidisciplinary Heart Team Approach

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

The heart team should assess:

• Valve morphology and feasibility of repair 3, 1
• MR etiology (primary vs. secondary) 1, 2
• Patient comorbidities and frailty 1
• Surgical risk using STS-PROM score 1
• Organ system compromise and procedure-specific impediments 1
• Local surgical expertise and institutional repair rates 3

For secondary MR specifically: Input from a cardiologist with experience managing heart failure is essential, as the underlying LV dysfunction drives management decisions. 2

Key Pitfalls to Avoid

• Do not perform mitral valve replacement when repair is feasible in primary MR 2
• Do not use vasodilators in hypertrophic cardiomyopathy or mitral valve prolapse, as they can worsen MR severity 4
• Do not rely solely on the presence or absence of a systolic murmur to determine MR severity; if the murmur is limited to late systole only or not audible, severe MR is unlikely 3
• Do not assume secondary MR is a single entity: MR can arise from LV dilatation, LA dilatation in preserved EF, or atrial fibrillation, each requiring different considerations 3