Study of Biomechanics of the Heart Valve Leaflet Apparatus Using Numerical Simulation Method

Area of Science:

• Biomedical Engineering
• Computational Mechanics
• Cardiovascular Devices

Background:

• Aortic valve prostheses are crucial for cardiovascular health.
• Understanding prosthesis biomechanics is key to improving design and function.
• Previous models often simplified the complex interaction between the prosthesis frame and leaflets.

Purpose of the Study:

• To simulate the complex biomechanics of an aortic valve prosthesis.
• To analyze the effect of frame mobility on leaflet stress, strain, and geometry.
• To validate numerical simulations against bench test results.

Main Methods:

• Utilized finite element analysis (FEA) in Abaqus/CAE for stress-strain analysis.
• Developed a high-resolution 3D model from micro-CT data of a UniLine bioprosthesis.
• Incorporated elastic connectors to simulate commissural strut mobility, validated with bench tests on a ViVitro Labs hydrodynamic system.

Main Results:

• The simulation accurately reproduced qualitative leaflet behavior and quantitative orifice area during the cardiac cycle.
• Identified stress concentrations near commissural struts and the free edge.
• Maximum stress values (0.850-0.907 MPa) remained below the biological material's ultimate strength.

Conclusions:

• FEA with a high-resolution model and elastic connectors accurately predicts aortic valve prosthesis biomechanics.
• Frame strut mobility is critical for prosthesis geometry and can be detrimental with highly elastic materials.
• The simulation method can optimize heart valve prosthesis design by assessing stress-strain distribution.