Augmented mitral valve leaflet area decreases leaflet stress: a finite element simulation.

Area of Science:

• Cardiovascular Biomechanics
• Medical Device Engineering
• Computational Fluid Dynamics

Background:

• Human mitral valve (MV) models were created using 3D echocardiography.
• Finite element analysis (FEA) was employed to predict mechanical stress on MV leaflets and chordae.
• Valve geometry modifications investigated the impact on stress distribution.

Purpose of the Study:

• To evaluate the effect of varying coaptation area on mitral valve stress.
• To determine how non-coapted leaflet tissue area influences mechanical stresses.
• To assess the role of interleaflet friction in mitral valve function and stress.

Main Methods:

• Three human MV models were subjected to 80 mm Hg transvalvular pressure using FEA.
• Leaflet coaptation was adjusted to 10%, 50%, and 100% of actual length.
• Leaflet surface area was augmented, and interleaflet friction (μ) was varied (0, 0.05, 0.3).

Main Results:

• Leaflet coaptation length did not significantly impact leaflet or chordal stress distribution.
• Increased non-coapted leaflet area led to a 5% decrease in peak valvular stress (p=0.02).
• Varying interleaflet friction did not alter leaflet or chordal stress patterns.

Conclusions:

• Excess mitral valve leaflet tissue effectively reduces mechanical stress on non-coapted regions.
• Mitral valve repair techniques that augment or preserve non-coapted leaflet area may enhance repair longevity.
• Coaptation extent and interleaflet friction do not independently affect leaflet stresses.