Evaluation of pliable bioresorbable, elastomeric aortic valve prostheses in sheep during 12 months post implantation

This preclinical study evaluated the in vivo functionality and remodeling behavior of bioresorbable, pliable elastomeric heart valve prostheses fabricated from bis-urea-modified polycarbonate (PC-BU). Implanted in the aortic position of sheep for up to 12 months, the valves were assessed for durability, calcification, cell colonization, and tissue formation. Most valves remained pliable and structurally intact, free of thrombotic or calcific complications, though some exhibited cusp thickening or perforations. Histological analysis revealed limited cell infiltration and collagen deposition mainly in hinge regions, with minimal scaffold resorption. These findings demonstrate partial success in creating functional in situ tissue-engineered aortic valves, highlighting the challenge of achieving balanced tissue regeneration under systemic pressure.