Manufacturing and hydrodynamic assessment of a novel aortic valve made of a new nanocomposite polymer

Abstract Synthetic leaflet heart valves have been widely studied as possible alternatives to the current mechanical and bioprosthetic valves. Assessing the in vitro hydrodynamic function of these prostheses is of great importance to predict their hemodynamic behaviour prior to implantation. This study introduces an innovative concept of a low-profile semi-stented surgical aortic valve (SSAV) made of a novel nanocomposite polyurethane with a polycarbonate soft segment (PCU) and polyhedral oligomeric silsesquioxane (POSS) nanoparticles covalently bonded as a pendant cage to the hard segment. The POSS–PCU is already used in surgical implants, including lacrimal duct, bypass graft, and recently, a tracheal replacement. Nine valves of three leaflet thicknesses (100, 150 and 200 μm) and 21 mm internal diameter were prepared using an automated dip-coating procedure, and assessed in vitro for their hydrodynamic performance on a pulse duplicator system. A commercially available porcine bioprosthetic valve (Epic™, St. Jude Medical) of equivalent size was selected as a control model. Compared to the bioprosthetic valve, the SSAVs showed a considerably lower transvalvular pressure drop and larger effective orifice area (EOA). They were also characterised by a lower systolic energy loss, especially at high cardiac outputs. The leaflet thickness was found to significantly affect the hydrodynamics of these valves ( P