What is the management approach for a patient with severe mitral regurgitation, considering symptoms, left ventricular dysfunction, and potential comorbidities?

Management of Severe Mitral Regurgitation

Surgery is the definitive treatment for severe mitral regurgitation, with specific indications determined by whether the MR is primary (valve pathology) or secondary (ventricular dysfunction), symptom status, left ventricular function parameters, and surgical risk. 1

Initial Classification: Primary vs. Secondary MR

The fundamental first step is determining the etiology through echocardiography, as management pathways diverge completely based on this distinction. 2, 3

• Primary MR results from intrinsic valve pathology (degenerative disease, flail leaflet, prolapse, endocarditis) 2
• Secondary MR results from left ventricular dysfunction causing annular dilatation or papillary muscle displacement 1, 2

Management of Primary Mitral Regurgitation

Symptomatic Patients

Surgery is indicated for all symptomatic patients with severe primary MR and LVEF >30%. 1 Mitral valve repair is strongly preferred over replacement when durable repair is technically feasible. 1

• Early surgery (within 2 months of indication) is associated with better outcomes, as even mild symptoms indicate deleterious cardiac changes 1
• Delaying intervention until severe symptoms or LV dysfunction develops leads to worse postoperative outcomes 2, 3

Asymptomatic Patients

Surgery is indicated in asymptomatic patients when LV dysfunction develops, defined as LVESD ≥45 mm and/or LVEF ≤60%. 1

Surgery should be considered in asymptomatic patients with preserved LV function when: 1

• New-onset atrial fibrillation develops 1, 3
• Pulmonary hypertension (systolic PAP >50 mmHg at rest) is present 1
• Flail leaflet with LVESD ≥40 mm 1

Surgery may be considered when high likelihood of durable repair exists at low surgical risk with: 1

• Left atrial volume index ≥60 mL/m² BSA in sinus rhythm 1
• Pulmonary hypertension on exercise (systolic PAP ≥60 mmHg) 1

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

TEER may be considered only in patients with symptomatic severe primary MR who are at high or prohibitive surgical risk as assessed by the Heart Team. 1 This is a Class IIb recommendation, reflecting limited evidence for this approach in primary MR. 1

Management of Secondary Mitral Regurgitation

Optimal guideline-directed medical therapy (GDMT) is mandatory as the first step for all patients with secondary MR, as severity is dynamic and changes with loading conditions, blood pressure, volume status, and heart rate. 1, 2, 3

Medical Optimization

• Diuretics for fluid overload 2
• ACE inhibitors for heart failure symptoms 2
• Aldosterone antagonists if symptoms persist 2
• Beta-blockers for rate control and ventricular arrhythmia prevention 3
• 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 2, 3

Reassess MR severity after optimized medical treatment before deciding on intervention. 2, 3

Surgical Indications for Secondary MR

Surgery is indicated in patients with severe secondary MR undergoing CABG with LVEF >30%. 1

Surgery may be considered in patients with severe secondary MR who: 1

• Remain symptomatic despite optimal medical therapy (including CRT if indicated)
• Have LVEF >30%
• Are at low surgical risk
• Do not have indication for revascularization

There is no conclusive evidence for a survival benefit after mitral valve intervention in isolated secondary MR. 1 The European guidelines emphasize that restoration of valve competence is not curative in secondary MR, as it is only one component of the underlying cardiomyopathy. 1

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

TEER should be considered in patients with severe secondary MR who: 1

• Remain symptomatic despite optimal GDMT
• Have LVEF 20%-50%
• Have LVESD ≤70 mm
• Have systolic PAP ≤70 mmHg
• Have appropriate anatomy suggesting increased chance of responding to TEER
• Are at high surgical risk or inoperable

This represents a Class IIa-B recommendation, reflecting stronger evidence for TEER in secondary MR (particularly based on COAPT trial criteria) compared to primary MR. 1

Acute Severe Mitral Regurgitation

In acute MR (e.g., papillary muscle rupture, chordal rupture, endocarditis): 1, 3

• Immediate hemodynamic stabilization with nitrates and diuretics to reduce filling pressures 1
• Sodium nitroprusside reduces afterload and regurgitant fraction 1
• Intra-aortic balloon pump for hemodynamic support 1
• Inotropic agents if hypotension develops 1
• Papillary muscle rupture (typically 2-7 days post-MI) is a surgical emergency requiring urgent intervention 3

Follow-Up Protocol

• Moderate MR: Clinical evaluation every 6-12 months with annual echocardiography 2
• Severe MR: Clinical evaluation every 6 months with annual echocardiography 2
• Exercise echocardiography when exercise-induced symptoms are present to assess dynamic worsening 2

Critical Pitfalls to Avoid

• Do not use vasodilators (including ACE inhibitors) chronically in primary MR with preserved LV function, as there is no evidence supporting their use 1
• Do not delay surgery in primary MR until severe symptoms or significant LV dysfunction develops, as this leads to irreversible ventricular damage and worse outcomes 2, 3
• Do not fail to recognize the dynamic nature of secondary MR—always reassess severity after medical optimization before considering intervention 2, 3
• Do not intervene on secondary MR without first optimizing GDMT including CRT if indicated, as medical therapy may significantly reduce MR severity 1, 2
• Outcomes of mitral valve repair depend heavily on surgeon experience and center-related volume—referral to experienced centers is essential 1