Omer Tal, Yevgeniy Kreinin, Dmitry Korneyev, Shulamit Levenberg, Netanel Korin
Biomimetic fiber reinforcement reduced predicted leaflet mechanical demand, particularly in strain energy density, while limiting its effect on valve performance. Leaflet thickness and reinforcement architecture should be optimized jointly to balance mechanical support and valve function.
PURPOSE: Polymeric heart valves (PHVs) remain limited by adverse leaflet mechanics and durability challenges. This study investigated biomimetic fiber reinforcement to improve leaflet mechanics while limiting effects on valve function.
METHODS: Polycarbonate urethane (PCU) leaflets containing encapsulated polyethylene terephthalate glycol (PETG) fibers were fabricated by multi-material 3D printing and heat-assisted compression. Unreinforced, horizontal, ply, and biomimetic configurations were evaluated by finite element (FE) analysis at 0.3-mm and 0.2-mm leaflet thicknesses. Characterization included notched testing and scanning electron microscopy. Pulse duplicator testing of 0.2-mm valves measured geometric orifice area (GOA), effective orifice area (EOA), and regurgitation fraction (RF).
RESULTS: The manufacturing approach produced embedded reinforcement architectures, and microscopy confirmed that fibers remained encapsulated, with no visible interfacial debonding after short-term hydrodynamic loading. Notched testing showed orientation-dependent behavior; 45° reinforcement increased maximum nominal ligament stress relative to unreinforced PCU. Reinforcement redistributed leaflet loading, with effects more pronounced at reduced thickness. The biomimetic configuration yielded the lowest predicted strain energy density, 22% and 26% lower than in unreinforced 0.3- and 0.2-mm valves, respectively. Experimental GOA measurements followed the FE trend. Although reinforcement reduced GOA, EOA differed modestly among configurations, while RF did not differ significantly. Overall, the biomimetic architecture provided the most favorable balance between mechanical response and valve opening among reinforced designs.
CONCLUSIONS: Biomimetic fiber reinforcement reduced predicted leaflet mechanical demand, particularly in strain energy density, while limiting its effect on valve performance. Leaflet thickness and reinforcement architecture should be optimized jointly to balance mechanical support and valve function.