Mapping the spatial variation of mitral valve elastic properties using air-pulse optical coherence elastography

Area of Science:

• Biomedical Engineering
• Tissue Mechanics
• Cardiovascular Research

Background:

• The mitral valve's complex structure, with anterior and posterior leaflets, is crucial for heart function.
• Traditional mechanical testing methods for mitral valve tissue have limitations in spatial resolution and can be destructive.

Purpose of the Study:

• To investigate the spatial variations in mitral valve leaflet mechanical properties using a novel noninvasive technique.
• To compare the elastic properties between the anterior and posterior mitral valve leaflets with micro-scale resolution.

Main Methods:

• Air-pulse optical coherence elastography (OCE) was used to measure elastic properties at 1 mm increments along leaflet length.
• Measurements were taken noninvasively and nondestructively, providing micro-scale resolution.
• Results were validated using established uniaxial tensile testing methods.

Main Results:

• The anterior leaflet exhibited higher elastic wave velocity (stiffness) than the posterior leaflet, particularly at the annular edge.
• A distinct elastic gradient was observed in the anterior leaflet, with greater stiffness at the annular edge compared to the free edge.
• The posterior leaflet showed a less pronounced elastic gradient.

Conclusions:

• The anterior mitral valve leaflet is mechanically stiffer and more heterogeneous than the posterior leaflet.
• Air-pulse OCE provides high-resolution insights into mitral valve mechanics, surpassing traditional methods.
• This technique holds potential for evaluating mitral valve repair outcomes and developing artificial valve replacements.