What is the treatment approach for a patient with myxomatous degeneration of the anterior mitral leaflet?

Treatment of Myxomatous Degeneration of the Anterior Mitral Leaflet

For myxomatous degeneration of the anterior mitral leaflet causing significant mitral regurgitation, surgical repair using nonresection techniques with PTFE neochord reconstruction or chordal transfer combined with annuloplasty ring is the definitive treatment, and these patients should be referred to experienced mitral valve surgeons at high-volume centers due to the technical complexity. 1

Surgical Approach for Anterior Leaflet Myxomatous Disease

Preferred Surgical Technique:

• Nonresection techniques using PTFE neochord reconstruction or ipsilateral chordal transfer from secondary to primary position, combined with annuloplasty ring 1
• This approach is specifically recommended for isolated anterior leaflet prolapse 1
• Focal triangular resection is rarely used for focal anterior leaflet defects 1

Critical Referral Consideration:

• Patients with anterior leaflet, bileaflet, or Barlow's disease requiring extensive and complex reparative techniques should be preferentially referred to an experienced mitral valve surgeon at a high-volume institution 1
• The majority of experienced surgeons can successfully repair focal posterior prolapse, but anterior leaflet pathology requires more specific expertise 1

Surgical Timing Based on Severity

Symptomatic Patients:

• Surgery is indicated for all symptomatic patients with severe MR and LVEF >30% 2, 3
• Do not delay surgery until symptoms develop, as symptom onset is itself a negative prognostic event even with preserved LV function 2, 3

Asymptomatic Patients - Surgery Indicated When ANY of the Following Develop:

• Left ventricular ejection fraction <60% 2, 3, 4
• Left ventricular end-systolic dimension ≥40 mm 2, 3, 4
• New-onset atrial fibrillation 2, 3, 4
• Pulmonary hypertension (systolic PAP >50 mmHg at rest) 2, 3, 4

Repair vs. Replacement Decision

Mitral valve repair is strongly preferred over replacement when technically feasible 2, 3, 4

Repair Should NOT Be Attempted Without Referral to Expert Centers When:

• Bileaflet prolapse is present 3
• Barlow's disease (diffuse myxomatous degeneration) is present 1
• Prior cardiac operation or chest radiation increases surgical risk 1

Valve Replacement May Be Considered:

• Only after repair has been attempted and was unsuccessful 1
• In patients with prior cardiac surgery where reoperation for failed repair would carry substantially increased risk 1

Medical Management (Non-Surgical Candidates or Preoperative)

No Role for Vasodilators:

• There is no evidence supporting the use of vasodilators, including ACE inhibitors, in chronic primary MR without heart failure 2, 3

Medical Therapy Indications:

• ACE inhibitors should be used in patients with advanced MR and severe symptoms who are not surgical candidates 2, 3
• Beta-blockers for symptomatic arrhythmias or palpitations 4
• Anticoagulation (target INR 2-3) for permanent or paroxysmal atrial fibrillation, history of systemic embolism, or left atrial thrombus 2, 3

Surveillance Protocol

For Moderate MR (Asymptomatic):

• Clinical follow-up every 6 months 2, 3
• Echocardiography annually 2, 3

For Severe MR (Asymptomatic):

• Clinical evaluation every 6 months 2, 3
• Echocardiography annually 2, 3

Predictors of Outcomes

Factors Associated with Worse Long-Term Outcomes:

• Lower percent of age/sex-predicted metabolic equivalents on exercise testing 5
• Lower heart rate recovery after exercise 5
• Atrial fibrillation 5
• Lower LV ejection fraction 5
• High resting right ventricular systolic pressure 5

Factors Associated with Recurrent MR After Repair:

• Advanced age 6
• Isolated prolapse of the anterior leaflet 6
• Degree of myxomatous changes in the mitral valve 6
• Lack of mitral annuloplasty 6
• Presence of moderate or greater residual MR at the time of the index operation 1

Critical Pitfalls to Avoid

• Never delay surgery until symptoms develop or LV dysfunction occurs, as earlier intervention leads to improved survival and functional outcomes 2, 3
• Do not perform valve replacement without attempting repair in patients with isolated anterior leaflet prolapse 1
• Do not refer complex anterior leaflet pathology to surgeons without specific mitral valve repair expertise 1
• The most important predictor of long-term failure is the presence of moderate or greater residual MR at the time of surgery 1
• Advanced myxomatous degeneration with posterior displacement of the mitral annulus has higher rates of late recurrent regurgitation despite technically successful repair 7