Mitral Valve Repair: Indications and Management
Primary Mitral Regurgitation
Mitral valve repair is strongly recommended over replacement for chronic severe primary MR when surgical intervention is indicated, particularly for posterior leaflet disease where success rates exceed 95%. 1
Class I Indications for Surgery
Symptomatic patients (Stage D):
- Severe primary MR with LVEF >30% 1
- Symptoms include exertional dyspnea, decreased exercise tolerance (NYHA class II-IV)
Asymptomatic patients with LV dysfunction (Stage C2):
- LVEF 30-60% and/or LVESD ≥40 mm 1
- This represents established LV dysfunction requiring intervention
Class IIa Indications (Reasonable to Consider)
Asymptomatic patients with preserved LV function (Stage C1):
- LVEF >60% AND LVESD <40 mm when:
Critical thresholds from recent research: Consider surgery before LVEF drops below 65% or left atrial volume index reaches 53 mL/m², as these predict postoperative LV dysfunction and worse long-term survival 3. Earlier intervention (LVEF >63% and LVESD <39 mm) preserves long-term LV function better 4.
Repair vs. Replacement Decision
Repair is strongly preferred when:
- Posterior leaflet disease (isolated) - repair mandatory unless attempted and failed 1, 5
- Anterior or bileaflet disease when successful durable repair achievable 1, 5
- Up to half the posterior leaflet can be resected with excellent outcomes 5
Replacement may be considered when:
- Severe annular or leaflet calcification present 6
- Prior repair attempts unsuccessful at experienced centers 5
- Unfavorable morphological characteristics for repair 7
Surgical Techniques
Posterior leaflet repair:
- Quadrangular/triangular resection with annuloplasty
- Neochordal implantation (loop technique)
- Success rate >95%, freedom from reoperation ~95% at 15-20 years 5
Complex repairs (anterior/bileaflet):
- Artificial chordae (PTFE) implantation
- Leaflet resection/sliding plasty
- Annuloplasty with rigid complete ring
- Freedom from reoperation ~80% at 15-20 years 5
Common pitfall: Residual moderate or greater MR at index operation is the strongest predictor of long-term failure 5. Ensure complete repair intraoperatively.
Secondary (Functional) Mitral Regurgitation
The evidence for isolated mitral intervention in secondary MR is weak, with no proven survival benefit. 7
Class I Indication
Concomitant surgery:
- Severe secondary MR undergoing CABG with LVEF >30% 7
- Use restrictive undersized rigid annuloplasty ring 8, 6
Class IIb Considerations
Isolated mitral surgery may be considered:
- Symptomatic patients despite optimal medical therapy (including CRT if indicated)
- LVEF >30%
- Low surgical risk
- No indication for revascularization 7
Lower thresholds define severe secondary MR: ERO ≥0.20 cm² and regurgitant volume ≥30 mL (versus ≥0.40 cm² and ≥60 mL for primary MR) 7
Transcatheter Edge-to-Edge Repair (TEER)
May be considered for:
- High surgical risk patients with appropriate anatomy
- LVEF 20-50%, LVESD ≤70 mm, PASP ≤70 mmHg
- Symptomatic despite optimal medical therapy 8
- Avoid in patients where intervention appears futile 7
Postoperative Management
Immediate postoperative assessment:
- TTE prior to discharge or within 1-3 months 6
- Verify no residual moderate or greater MR
- Assess LV function recovery
Surveillance for successful repair:
- Asymptomatic with severe MR: every 6-12 months preoperatively 8
- Post-repair: annual clinical follow-up with TTE as clinically indicated
- Freedom from severe MR after re-repair: 93% at 7 years 9
Anticoagulation:
- Mechanical valve: lifelong warfarin (INR 2.5-3.5 for mitral position) 7
- Bioprosthetic valve: warfarin for 3-6 months, then aspirin
- Repair with annuloplasty ring: aspirin 81 mg daily; consider warfarin for 3 months if atrial fibrillation present
Medical therapy optimization:
- Heart failure management per guidelines (ACE-I/ARB, beta-blockers, MRA) for secondary MR 7, 8
- CRT if indicated (QRS ≥150 ms, LVEF ≤35%) 7
- Antibiotic prophylaxis NOT routinely recommended post-repair
Key principle: Surgeon and center experience critically impact outcomes. Complex repairs should be performed at high-volume centers (>36 mitral operations/year) with documented repair rates >90% and mortality <1% 5.