HOW TO INHIBIT CALCIFICATION ON A POLYMER HEART VALVE

Purpose: We have been developing a polymer heart valve (Jellyfish Valve). In the present improved Jellyfish Valve (IJF), the maximal strain of the membrane could be reduced by 50%, as compared with the original one. Previous in vitro accelerated fatigue tests successfully exhibited that the estimated lifetime was up to 8 years in vivo. Therefore, the present aim is to examine an influence of mechanical strain on calcification. Methods: In a total artificial heart (TAH) model, 18 goat experiments of the IJFs were performed. In a left ventricular assist device (LVAD) model, the following 3 experiments were performed. 1) The original Jellyfish Valves (OJFs) were used for 196 days. 2) The OJF and the IJF were used in both inlet and outlet for 113 days. 3) The IJFs were used for 240 days. In all experiments, neither anticoagulant nor antiplatelet agents were administered postoperatively. Results: In all valves, no thrombus were observed. In TAH experiments, the longest period was 64 days. All the membranes of the valves subjected to the LVAD experiments were inspected by scanning electron microscope, Dahl staining, and X-ray microanalyzer. As for the OJFs used for 196 days and for 113 days, calcification composed of Ca and P were detected at specific regions where mechanical strain is highly concentrated. However, as for the IJFs used for 240 days and for 113 days, calcification could be successfully inhibited. Therefore, it was revealed that reduction of mechanical strain has a great importance to inhibit calcification on polymer cardiovascular devices.