A New Single - Body Silicone - Polycarbonate - Urethane/PDMS Heart Valves: Material Characterization And Prototype Realization

Polymeric heart valves (PHVs) have been investigated since 1960 but their success has been hampered by an overall lack of durability, due to leaflets calcification and thromboembolic complications. The aim of this work was to study a new elastomeric material for the development of a single-body PHV. CarboSil® (CS) was dissolved in THF/DM Ac 1:1 (v/v) to obtain a 2% (w/v) solution. CarboSil® solutions containing 10% (CS10) and 30% of PDMS (CS30) were obtained by a reaction under stirring and nitrogen flow for 6 h at 82 °C. For each materials planar patches were obtained by a spray, phase-inversion technique on a rotating cylindrical mandrel. In vitro tests were carried out to evaluate: bio/hemocompatibility, calcification, hydrolytic degradation, oxidative degradation, environmental stress cracking (ESC) degradation, and mechanical properties. Materials extracts showed no cytotoxic effects on mouse fibroblasts respect to untreated cells. CS30 induced a lower in vitro platelets adhesion than the CS one. Coagulation times were similar for all tested materials. CS10 and CS30 showed less calcification spots compared to CS (SEM). IR demonstrated no significant differences among CS, CS10 and CS30 samples after hydrolytic degradation. CS30 was less susceptibility to oxidative degradation and to ESC. No mechanical differences were found between a ll materials. A single-body PHV prototype, with an incorporated stent, was successfully obtained by spray, phase-inversion technique with CS30. CarboSil® -PDMS processed by the spray material deposition on a 3D mould, allowed the feasibility of a new low-cost and potentially long-term performing PHV.