A design-based model of the aortic valve for fluid-structure interaction

Area of Science:

• Biomedical Engineering
• Computational Fluid Dynamics
• Cardiovascular Mechanics

Background:

• Aortic valve dysfunction affects millions globally, necessitating improved understanding and treatment.
• Current models often lack the precision to capture complex leaflet mechanics under physiological loads.
• Accurate simulation of aortic valve function is crucial for developing effective prosthetic devices.

Purpose of the Study:

• To develop a novel, first-principles-based computational model for aortic valve mechanics.
• To simulate the fluid-structure interaction between the aortic valve and blood flow.
• To derive insights into optimal design parameters for prosthetic aortic valves.

Main Methods:

• Derivation of partial differential equations governing leaflet mechanical equilibrium based on pressure support requirements.
• Development of a predicted loaded configuration, reference configuration, and constitutive law.
• Fluid-structure interaction simulations using the immersed boundary method.

Main Results:

• The model demonstrates reliable sealing under physiological pressures and free opening over cardiac cycles.
• Valve closure remains robust across a wide range of pressures (hypotensive to hypertensive).
• Key determinants of valve function include loaded geometry, tensions, and tangent moduli.

Conclusions:

• Nonlinear material response is essential for valve function across varying pressures.
• Prosthetic valve design should prioritize specific gross morphology and material properties, particularly free edge length and leaflet height.
• The developed modeling framework is adaptable for patient-specific vascular and cardiac flow simulations.