Is the anterior leaflet folded during mitral valve repair with an annuloplasty ring?

Mitral Valve Repair with Annuloplasty Ring: Anterior Leaflet Management

The anterior leaflet is not folded during mitral valve repair with an annuloplasty ring. Instead, the anterior leaflet is typically preserved at its full height while the posterior leaflet may be reduced in height through various techniques to prevent systolic anterior motion (SAM) and optimize valve geometry 1.

Surgical Approach to Leaflet Management

Anterior Leaflet Preservation

• The anterior leaflet maintains its natural configuration and is not folded or reduced in height during standard mitral valve repair 1
• Nonresection techniques using PTFE neochord reconstruction or chordal transfer are employed for anterior leaflet prolapse, preserving the leaflet structure while restoring proper coaptation 1, 2
• Focal triangular resection is rarely used for anterior leaflet defects, and when performed, involves excision rather than folding 1

Posterior Leaflet Modification

• The posterior leaflet is frequently reduced in height through sliding leaflet valvuloplasty or resection techniques, particularly in cases with excess leaflet tissue 1
• Sliding leaflet technique specifically reduces posterior leaflet height to prevent SAM of the anterior leaflet, which occurs when excess tissue causes the anterior leaflet to be pushed into the left ventricular outflow tract 3
• This approach eliminates significant LVOTO in high-risk patients, reducing SAM incidence from 14% to 2.4% 3

Prevention of Systolic Anterior Motion

Key Strategies

• Large annuloplasty rings (sizes 36-40mm) are used in patients with excess leaflet tissue (Barlow's disease) to accommodate the anterior leaflet without causing SAM 4, 5
• The Medtronic Simulus ring, which has the largest anterior-posterior diameter among available rings, shows excellent results with no SAM development in patients with abundant leaflet tissue 5
• Sliding leaflet valvuloplasty is specifically indicated when echocardiographic predictors of SAM are present, reducing posterior leaflet height while maintaining anterior leaflet integrity 1

Anatomic Considerations

• Excess anterior leaflet tissue, non-dilated left ventricular cavity, and narrow mitro-aortic angle are major risk factors for post-repair LVOTO 3
• The anterior leaflet must maintain adequate mobility and height to achieve proper coaptation with the modified posterior leaflet 3

Technical Complexity and Referral Patterns

High-Risk Pathology

• Patients with anterior leaflet prolapse, bileaflet involvement, or Barlow's disease require referral to experienced mitral valve surgeons at high-volume centers due to technical complexity 1, 6, 7
• Single segment posterior leaflet flail has the highest repair success rate and can be managed by most experienced surgeons 7

Repair Techniques by Pathology

• Focal posterior prolapse: triangular resection with annuloplasty ring 1
• Anterior leaflet prolapse: nonresection techniques with neochord reconstruction and annuloplasty ring 1, 2
• Bileaflet prolapse with excess posterior leaflet: sliding leaflet valvuloplasty with annuloplasty ring 1
• Forme fruste myxomatous disease: may use either nonresection or sliding techniques depending on leaflet involvement 1

Critical Pitfalls to Avoid

• Do not attempt to reduce anterior leaflet height through folding or resection in standard repair, as this compromises valve function and coaptation 1
• Undersized annuloplasty rings alter valve geometry and elevate tissue stresses, causing pathological leaflet remodeling with increased procollagen-1, heat shock protein-47, and transforming growth factor-β expression 8
• The presence of moderate or greater residual MR at the time of surgery is the most important predictor of long-term repair failure 1, 7
• Inadequate posterior leaflet reduction in patients with excess tissue increases SAM risk and repair failure 3