What are the guidelines for mitral valve replacement in patients with severe myxomatous mitral valve degeneration?

Guidelines for Mitral Valve Replacement in Severe Myxomatous Mitral Valve Degeneration

For patients with severe myxomatous mitral valve degeneration, mitral valve repair is strongly recommended over mitral valve replacement whenever a successful and durable repair can be accomplished. 1

Indications for Surgical Intervention

Class I Recommendations (Strongest)

1. Symptomatic patients (Stage D)

   • Surgery is recommended for patients with chronic severe primary MR who are symptomatic (NYHA class II-IV) with LVEF >30% 1
   • This represents a clear indication for intervention to improve mortality and quality of life

2. Asymptomatic patients with LV dysfunction (Stage C2)

   • Surgery is recommended when LVEF is 30-60% and/or LVESD ≥40 mm 1
   • Early intervention prevents irreversible LV damage and improves long-term outcomes

3. Concomitant surgery

   • Mitral valve repair/replacement is indicated in patients with chronic severe primary MR undergoing cardiac surgery for other indications 1

Class IIa Recommendations (Reasonable)

1. Asymptomatic patients with preserved LV function (Stage C1)

   • Repair is reasonable when:
     • LVEF >60% and LVESD <40 mm
     • High likelihood (>95%) of successful and durable repair
     • Low expected mortality (<1%)
     • Performed at a Heart Valve Center of Excellence 1

2. Asymptomatic patients with preserved LV function and risk factors

   • Repair is reasonable with:
     • New onset atrial fibrillation, or
     • Pulmonary hypertension (PA systolic pressure >50 mmHg) 1
     • Recent evidence suggests considering repair when indexed LVESD >19 mm/m² or RVSP >45 mmHg 2

Repair vs. Replacement Decision Algorithm

1. Always prefer repair over replacement when possible 1

   • Repair preserves subvalvular apparatus and LV function
   • Avoids long-term anticoagulation complications
   • Associated with better long-term survival

2. Specific anatomical considerations:

   • Posterior leaflet pathology: Strong preference for repair (Class I) 1
   • Anterior or bileaflet involvement: Repair preferred when durable repair is feasible (Class I) 1
   • Advanced myxomatous degeneration: Despite technical challenges, repair shows excellent early results 3, 4

3. When replacement becomes necessary:

   • When repair is not feasible or likely to be durable
   • Complex pathology beyond repair expertise
   • Severe calcification of the leaflets or annulus
   • Extensive involvement of multiple scallops

Important Considerations and Pitfalls

1. Surgical expertise is critical

   • Outcomes are directly related to surgeon and center experience
   • Referral to Heart Valve Centers of Excellence for complex repairs

2. Long-term durability

   • While repair is preferred, recurrent MR can occur in 5-20% of cases by 10-16 years 3, 4
   • Advanced myxomatous degeneration with annular displacement presents higher technical challenges 3

3. Timing of intervention

   • Waiting until symptoms develop may result in irreversible LV damage
   • Early repair in asymptomatic patients requires high likelihood of successful repair and low operative risk

4. Minimally invasive approaches

   • Edge-to-edge repair techniques show excellent long-term durability (up to 19 years) in selected patients 4
   • Transcatheter options only for prohibitive surgical risk patients 1

5. Age considerations

   • Older patients with severe MR can still benefit from valve intervention with low mortality and good long-term results 5

The decision between repair and replacement should be made by an experienced heart team, with repair strongly preferred whenever feasible. Replacement should only be considered when repair is not technically possible or unlikely to provide durable results.