Preclinical Feasibility and Structural Optimization of a 3D-Printed Silicone-Based Pulmonary Valve Prosthesis: An In Vitro Evaluation

Background: Conventional bioprosthetic valves face early calcification and structural degradation, which often necessitate high-risk reoperations in pediatric patients.This pilot study evaluated the preclinical feasibility of a novel 3-dimensional (3D)-printed siliconebased pulmonary valve prosthesis.The analysis focused on structurally informed design features intended to maintain functional stability and mechanical durability.Methods: The valve was fabricated from medical-grade silicone elastomer using digital light processing 3D printing.Structural refinements, including thickened leaflet edges, a helical propeller-like geometry, and integrated leaflet tips, were incorporated.Hydrodynamic performance was evaluated in 2 valves using a pulsatile mock circulation system in accordance with ISO 5840-3:2013 standards under normotensive (20 mmHg) and hypertensive (50 mmHg) conditions.Preliminary biocompatibility was assessed using WST-1 cytotoxicity assays (n = 8) in RAW 264.7 cells exposed to silicone extracts at 0.1 wt% and 1 wt%.Results: The 3D-printed valve demonstrated satisfactory functional stability within the tested parameters.The effective orifice area ranged from 1.71 to 1.78 cm 2 , exceeding the ISO minimum requirement of 1.70 cm 2 .The mean peak-to-peak pressure difference was maintained at approximately 15.05 mmHg, indicating acceptable flow resistance.The regurgitation volume ratio ranged from 8.0% to 15.8%, remaining within the 20% acceptance threshold.Analysis of closing volume and leakage volume indicated reliable leaflet response and diastolic sealing.Cytotoxicity testing demonstrated cell viability of 73.2% and 75.4% at 0.1 wt% and 1 wt%, respectively, both exceeding the 70% non-cytotoxicity threshold, with no significant differences compared with the control group (P > 0.05).Conclusions: This feasibility study suggests that integrating 3D printing technology with structurally informed silicone design can yield a mechanically viable pulmonary valve prototype.Although the results demonstrated promising in vitro performance, this work provides a preliminary foundation for a multistage clinical development roadmap, including advanced hemocompatibility assessment and long-term in vivo validation for potential future transcatheter applications.