Thrombogenic Risk Assessment of Transcatheter Prosthetic Heart Valves Using a Fluid-Structure Interaction Approach.

Area of Science:

• Biomedical Engineering
• Computational Fluid Dynamics
• Cardiovascular Devices

Background:

• Transcatheter aortic valve replacement (TAVR) is increasingly common, but life-threatening thrombotic events remain a concern.
• Current in vitro thrombogenicity testing is challenging, necessitating advanced computational methods.
• Revised ISO standards now include computational testing for cardiovascular implant risk assessment.

Purpose of the Study:

• To develop and validate a fluid-structure interaction (FSI) approach for assessing the thrombogenic risk of transcatheter aortic valves (TAVR).
• To utilize this methodology for engineering optimization and clinical assessment of TAVR devices.
• To enhance the thromboresistance of prosthetic valves from design to clinical application.

Main Methods:

• Implemented an FSI framework using ANSYS LS-DYNA for computational fluid dynamics.
• Validated the numerical model by comparing in silico results with benchtop testing and literature data for commercial TAVR valves.
• Analyzed thrombogenic risk by computing stress accumulation (SA) on virtual platelets using ANSYS EnSight.

Main Results:

• In silico simulations accurately predicted TAVR valve performance, with flow rates matching experimental results by approximately 93%.
• Instantaneous platelet stresses reached around 10 Pa with various TAVR leaflet designs.
• Patient-specific modeling revealed significant thrombogenic risk in "mild" paravalvular leaks, with median SA nearly double the activation threshold.

Conclusions:

• The developed FSI methodology enables improved thromboresistance of prosthetic valves.
• It facilitates device optimization by identifying key leaflet design parameters to mitigate thrombogenic risk.
• The approach is valuable for patient-specific TAVR device evaluation and risk assessment of other blood-contacting devices.