What is the treatment for a patient with severe mitral regurgitation, possibly with atrial fibrillation and left ventricular dysfunction?

Treatment of Severe Mitral Regurgitation

Surgery is the definitive treatment for severe mitral regurgitation, with mitral valve repair preferred over replacement when technically feasible, and the specific approach depends critically on distinguishing primary (organic) from secondary (functional) MR. 1

Initial Diagnostic Approach

The first critical step is determining whether the MR is primary or secondary, as this fundamentally changes management:

• Primary MR results from intrinsic valve pathology (flail leaflet, prolapse, endocarditis, rheumatic disease) 1
• Secondary MR results from left ventricular dysfunction causing annular dilatation or papillary muscle displacement 1
• Perform comprehensive 2D and Doppler echocardiography to establish etiology, severity (EROA, regurgitant volume), LV dimensions (LVESD, LVEF), and assess if durable repair is feasible 2
• Note that secondary MR uses lower severity thresholds (EROA ≥20 mm² vs ≥40 mm² for primary) 3

Management of Primary (Organic) Mitral Regurgitation

Symptomatic Patients

All symptomatic patients with severe primary MR and LVEF >30% should undergo surgery immediately 1:

• Mitral valve repair is strongly preferred over replacement when durable repair is technically feasible 1
• Surgery should occur within 2 months of indication, as even mild symptoms indicate deleterious cardiac changes 1
• When LVEF is <30%, surgical repair may still improve symptoms, though survival benefit is uncertain; the decision requires weighing response to medical therapy, comorbidities, and likelihood of successful repair 4

Asymptomatic Patients

Surgery should be considered in asymptomatic patients with preserved LV function when any of the following develop 1:

• New-onset atrial fibrillation (AF significantly worsens long-term outcomes even after successful repair) 1, 5
• Pulmonary hypertension (associated with worse survival and event-free survival) 1, 5
• Flail leaflet with LVESD ≥40 mm (threshold associated with increased mortality) 4, 1
• Progressive LV dysfunction on serial imaging (≥3 studies showing increasing LV size or decreasing EF) 4

Critical caveat: Patients with AF and/or pulmonary hypertension have significantly worse long-term survival (67% vs 87% at 15 years), higher rates of recurrent MR, and reduced durability of repair, indicating they should be operated on earlier rather than waiting for symptoms 5. At the time of mitral valve surgery in patients with AF, atrial ablation and left atrial appendage closure may be considered 4.

Management of Secondary (Functional) Mitral Regurgitation

Medical Optimization First

Optimal guideline-directed medical therapy (GDMT) is mandatory as the first-line treatment for all patients with secondary MR 1:

• Initiate ACE inhibitors/ARBs, beta-blockers, and mineralocorticoid receptor antagonists 3
• Consider cardiac resynchronization therapy (CRT) if indicated for heart failure 3
• Reassess MR severity after medical optimization, as secondary MR is dynamic and changes with loading conditions, blood pressure, volume status, and heart rate 1, 3

Surgical Indications

Surgery for secondary MR is indicated in specific scenarios 1:

• Patients undergoing CABG with LVEF >30%: Concomitant mitral valve surgery is recommended (Class I) 1, 3
• Patients undergoing CABG with LVEF ≤30%: Mitral valve surgery may be considered (Class IIb) 3
• Symptomatic patients despite optimal GDMT: Surgery may be considered if LVEF >30% and surgical risk is low 1

For isolated mitral valve surgery in severe secondary MR with severe LV dysfunction who cannot be revascularized or have non-ischemic cardiomyopathy, conventional medical and device therapy are preferred over surgery 4. In selected cases, repair may be considered to avoid or postpone transplantation 4.

Transcatheter Edge-to-Edge Repair (TEER)

TEER serves as an alternative when surgery is high-risk or contraindicated:

Primary MR

• Consider TEER in symptomatic patients with severe primary MR who are at high or prohibitive surgical risk with favorable valve anatomy (Class IIb) 1

Secondary MR

• TEER should be considered in patients with severe secondary MR who remain symptomatic despite optimal GDMT, have LVEF 20-50%, and are at high surgical risk or inoperable (Class IIa-B) 1
• This represents a stronger indication than for primary MR 1

Acute Severe Mitral Regurgitation

When MR presents acutely (flail leaflet, papillary muscle rupture, endocarditis):

• Immediate hemodynamic stabilization with nitrates and diuretics 1
• Consider sodium nitroprusside, intra-aortic balloon pump, and inotropic agents as needed 1
• Papillary muscle rupture is a surgical emergency requiring urgent intervention 1, 6
• Acute primary MR typically requires early surgical intervention due to acute cardiovascular decompensation with abrupt increase in left atrial pressure 6

Critical Pitfalls to Avoid

• Do not use vasodilators chronically in primary MR with preserved LV function (no proven benefit and may delay appropriate surgery) 1
• Do not delay surgery in primary MR until severe symptoms or significant LV dysfunction develops (outcomes worsen with delay) 1
• Do not fail to recognize the dynamic nature of secondary MR (always optimize GDMT first and reassess) 1
• Do not proceed with intervention for secondary MR without optimizing GDMT including CRT if indicated 1
• Refer patients to experienced heart valve centers for mitral valve repair to ensure optimal outcomes 1

Follow-Up Protocol

• Moderate MR: Clinical evaluation every 6-12 months with annual echocardiography 1
• Severe MR: Clinical evaluation every 6 months with annual echocardiography 1