A Computational Tool for the Microstructure Optimization of a Polymeric Heart Valve Prosthesis.

Area of Science:

• Biomaterials Science
• Polymer Engineering
• Computational Mechanics

Background:

• Styrene-based block copolymers offer tunable mechanical properties for polymeric heart valve prostheses (PHV).
• Material anisotropy, achieved through manufacturing processes like domain orientation, is crucial for PHV performance.
• Optimizing the internal structure of PHV leaflets is key to improving device longevity and function.

Purpose of the Study:

• To develop a computational tool for optimizing the microstructure of a PHV for aortic valve replacement.
• To enhance the mechanical performance and durability of PHV devices through microstructure engineering.
• To investigate the relationship between polymer domain orientation and mechanical stress distribution in PHV leaflets.

Main Methods:

• Development of a computational tool employing an iterative procedure to orient cylindrical domains.
• Implementation of a numerical model for PHV leaflets using a hyperelastic anisotropic constitutive law.
• Alignment of polymer cylinders with the maximum principal stress direction during valve closure using a custom routine.

Main Results:

• The optimal microstructure exhibits a predominantly circumferential orientation of polymer cylinders within the valve leaflet.
• Microstructure optimization led to increased radial strain and decreased circumferential strain.
• A reduction in maximum strain energy density was observed, suggesting enhanced device durability.

Conclusions:

• The developed computational method is a valuable tool for designing anisotropic PHVs.
• Optimizing polymer microstructure can significantly increase the durability of PHV devices.
• This approach allows for the investigation of various PHV designs, materials, and loading conditions.