Parametric finite element modeling of reinforced polymeric leaflets for improved durability

Area of Science:

• Biomaterials Engineering
• Cardiovascular Devices
• Mechanical Engineering

Background:

• Polyethylene polymeric transcatheter aortic valve replacement (TAVR) with hyaluronic acid shows good initial performance.
• Durability issues, including impact wear and fatigue, lead to premature valve failure in current TAVR designs.
• Fiber reinforcement offers a potential solution to enhance heart valve leaflet strength and longevity.

Purpose of the Study:

• To investigate the efficacy of embedded braided polyester fibers in improving the durability of TAVR leaflets.
• To analyze the effects of fiber orientation, length, and number on leaflet stress and opening dynamics using Finite Element Analysis (FEA).
• To evaluate the in vitro performance and durability of fiber-reinforced TAVR devices.

Main Methods:

• Simulating the cardiac cycle using FEA to assess leaflet stress and opening dynamics with varying fiber configurations.
• Manufacturing and testing physically reinforced heart valves in an in vitro flow loop and wear tester.
• Comparing durability and hemodynamic performance against non-reinforced controls and established standards (ISO 5840-2005).

Main Results:

• Fiber reinforcement increased leaflet durability from millions to 73 million cycles.
• Horizontal fibers improved durability but compromised hemodynamics, increasing coaptation gap and reducing geometric orifice area (GOA).
• FEA predicted that 12 mm fibers in the commissure post region optimize stress, GOA, and leaflet opening dynamics.

Conclusions:

• Braided polyester fiber reinforcement is a viable strategy to significantly enhance TAVR leaflet durability.
• Optimized fiber placement (12 mm, commissure post region) can maintain or improve hemodynamic function while maximizing durability.
• This approach holds promise for developing longer-lasting and more reliable TAVR devices.