Effects of annular contraction on anterior leaflet strain using an in vitro simulator with a dynamically contracting mitral annulus

Abstract

Using in vitro models, the mechanics as well as surgical techniques for mitral valves (MV) and MV devices can be studied in a more controlled environment with minimal monetary investment and risk. However, these current models rely on certain simplifications, one being that the MV has a static, rigid annulus. In order to study more complex issues of imaging diagnostics and implanted device function, it would be more advantageous to verify their use for a dynamic environment in a dynamic simulator. This study provides the novel design and development of a dynamically contracting annulus (DCA) within an in vitro simulator, and its subsequent use to study MV biomechanics. Experiments were performed to study the ability of the DCA to reproduce the MV leaflet mechanics in vitro, as seen in vivo, as well as investigate how rigid annuloplasties affect MV leaflet mechanics. Experiments used healthy, excised MVs and normal hemodynamics; contractile waveforms were derived from human in vivo data. Stereophotogrammetry and echocardiography were used to measure anterior leaflet strain and the change in MV geometry. In pursuit of the first in vitro MV simulator that more completely represents the dynamic motion of the full valvular apparatus, this study demonstrated the successful operation of a dynamically contracting mitral annulus. It was seen that the diseased contractile state increased anterior leaflet strain compared to the healthy contractile state. In addition, it was also shown in vitro that simulated rigid annuloplasty increased mitral anterior leaflet strain compared to a healthy contraction.

Comparative transcriptomic profiling of myxomatous mitral valve disease in the cavalier King Charles spaniel

“…Morphological studies are needed to determine if there are differences in CKCS valve myocardium content compared to non-CKCS that may explain some of these transcriptomic differences. Indeed, there is emerging interest in valve contraction mechanics and how this is affected by or contributes to the diseased state, and in this context the relative contribution of valve cardiomyocytes needs to be considered [ 50 ].…”

Heart Valve Biomechanics: The Frontiers of Modeling Modalities and the Expansive Capabilities of Ex Vivo Heart Simulation

“…Extrapolating further, a recent publication focused on creating a dynamically contracting mitral annulus to recapitulate the natural annular changes. With stereophotogrammetry, the authors tracked the anterior leaflet of a porcine MV, identifying increased leaflet strain when implanting a rigid annuloplasty ring ( 81 ).…”