Manufacturing studies of a polymeric/composite heart valve prosthesis

• Published in: Polymer composites Vol. 45; no. 12; pp. 11076 - 11092
• Main Authors: Chen, Mary Jialu, Pappas, Georgios A., Smid, Caroline C., Cesarovic, Nikola, Falk, Volkmar, Ermanni, Paolo
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 20-08-2024; Blackwell Publishing Ltd
• Subjects: autoclave processing; Autoclaves; biomedical application; Bonding strength; Coating effects; Composite materials; Heart; Heart valves; Immersion coating; Manufacturing; Mechanical properties; Modulus of elasticity; Molds; Polyether ether ketones; polyetheretherketone; Prostheses; Rapid manufacturing; Stents; Surgical implants; Thermoforming; thin‐ply composites; Vacuum forming
• ISSN: 0272-8397; 1548-0569
• DOI: 10.1002/pc.28532

Current transcathether heart valves rely on metal mesh stents, resulting in discontinuous stent‐leaflet interfaces that introduce stress concentrations, reducing valve lifetime. This work aims to investigate non‐conventional methods to create a fully polymeric transcatheter heart valve, exhibiting a quasi‐continuous interface with hemocompatible leaflets with high durability potential. Polyetheretherketone (PEEK) is of particular interest as a cardiovascular material due to hemocompatibility and mechanical resilience, highly relevant for catheter delivered valves. For increased reproducibility and design freedom, an autoclave process was used to manufacture thin‐ply PEEK composite stents. We demonstrated that a suitable membrane material during manufacturing is essential to evenly distribute pressure around the stent. Meanwhile, a modified vacuum forming process was used to simultaneously form and attach PEEK leaflets to the stent using a heated mold. This simple and robust method enables rapid manufacturing of an integral PEEK‐based valve design, resulting in improved stent‐leaflet bonding, demonstrating an alternative to conventional dip‐coating. The customized vacuum forming causes a controlled annealing effect in semicrystalline materials such as PEEK. Processing PEEK leaflets at higher mold temperatures results in higher crystallinity, elastic modulus, and bond strength. These processes enable greater design flexibility and promote composite materials for use in heart valve devices.
Highlights
Developed manufacturing processes for PEEK‐based heart valve implants.
Proof of concept for thermoforming of semi‐crystalline PEEK leaflets.
Demonstrated effect of processing temperature on valve mechanical properties.
Autoclave processing and vacuum forming enable new heart valve designs.
Visual summary of experimental procedure from manufacturing to mechanical testing.