The effects of dynamic saddle annulus and leaflet length on transmitral flow pattern and leaflet stress of a bileaflet bioprosthetic mitral valve.
OBJECTIVE
The study aim was to determine the effect of mitral saddle annulus and leaflet length on peak leaflet stress and transmitral flow pattern when utilizing a novel bileaflet bioprosthetic valve.


METHODS
A novel valve, which closely mimics the saddle annulus motion of the mitral valve was developed. A series of computational analyses and in-vitro hemodynamic studies was performed to assess the effect of annulus dynamics and leaflet length on stress distribution at the leaflet tips as well as the transmitral flow pattern downstream of the valve.


RESULTS
The analysis showed that the dynamic annulus may significantly reduce stress along the tip of the leaflets compared to the rigid annulus in a standard trileaflet valve. The leaflet length may also significantly alter stress distribution over the leaflets by affecting the annulus dynamics. It was shown in vitro that the interaction between the leaflet and the ventricular results in fundamentally distinct transmitral vortex formation patterns.


CONCLUSIONS
Motion of the mitral saddle annulus along with the leaflet length is a critical factor that minimizes stress distribution at the tips of the leaflets due to a dampening of the pressure load exerted over the valve during the cardiac cycle. The length of the leaflets, and their proximity to the ventricular wall, have been shown to have significant effects on transmitral vortex formation and energy dissipation during blood transfer from the left atrium towards the aorta via left ventricle.
The Edwards Lifesciences Center for Advanced Cardiovascular Technology, The Henry Samueli School of Engineering, University of California, Irvine, Irvine, CA 92697, USA. arashkh@uci.edu
Arash
A
Kheradvar
Ahmad
A
Falahatpisheh
D001705:Bioprosthesis; D006350:Heart Valve Prosthesis; D008943:Mitral Valve / Q000502:physiology*; D008955:Models, Cardiovascular; D012212:Rheology; D013314:Stress, Mechanical