Innovative Sutureless Fabrication Strategy for Tissue-Engineered Pediatric Heart Valves Using an Evolutive Support System

Abstract Current pediatric heart valve protheses lack growth potential, leading to repeated surgeries and long-term complications. Tissue-engineered heart valves (TEHVs), composed of living tissue, offer the ability to remodel and may accommodate somatic growth. This study introduces a sutureless fabrication strategy for TEHV designed to eliminate suture-related weak points and preserve valve geometry during in vitro maturation through a novel evolutive support system. This system was used to form and maintain the geometry of a fibrin-based valve scaffold embedded with human adipose-derived stromal cells during in vitro culture by mechanically constraining tissue contraction in all directions except thickness. Dimensional analysis confirmed geometry preservation throughout 28 days of perfusion bioreactor culture. At the end of the culture period, the matured valve was released from the evolution support system, after which the valve contracted to stable dimensions of approximately 16 mm in diameter, 23 mm in height, and 400 µm in thickness, corresponding to reductions of 26%, 43%, and 84% in diameter, height, and thickness, respectively, relative to the initial molded geometry. These ratios provide critical design guidance for pediatric target dimensions. Cell viability exceeded 90% upon molding, and cell density increased nearly 100-fold during culture. Histology revealed progressive collagen deposition, which correlated with improved mechanical properties. Stiffness increased nearly 9-fold and puncture strength 2.5-fold from fabrication to day 28. This reproducible sutureless strategy enables geometry retention of TEHV by guiding tissue contraction during in vitro culture, paving the way for pulsatile conditioning and further maturation to achieve mechanical properties approaching those of native valves and ensure long-term functionality.