Prediction of durability of artificial organs using an accerelated fatigue tester

点击翻译按钮获取中文摘要

In order to predict a durability of heart valve prostheses, two types of commercially available (ISU-Standard) accerelated fatigue tests were employed, while improving a life time of Jellyfish polymer valve.A chronic animal experiment of Jellyfish valves incorporated into conventional sac-type blood pumps for over 300days exhibited that there were a fracture and calcification on this flexible membrane. Therefore, a long durability (approx. 1 year guarantee) of Jellyfish valve has been developing. while clearing a cause of the problems.First of all, design improvement of Jellyfish valve was attempted. Results of finite element analysis during closed phase of Jellyfish valve indicated that mechanical strain generated on valve membrane fracture and calcification in the animal experiment. Moreover further analysis suggested that an additional circular rim located at 7.0mm in radius was quite effective to avoid strain concentration. In vitro steady and pulsatile tests demonstrated that a modified valve with 0.5mm width rim located at 70mm in radius had a comparable hydrodynamic performance to the original Jellyfish valve.For the next step, commercially available two types of accelerated fatigue tests were employed. Fatigue tests successfully revealed that a durability of the modified valve was much more extended than the original Jellyfish valve by 7 times.Thus, chronic animal experiment with conventional sac-type blood pumps in which the modified valves were incorporated was performed for months. Hemolysis related to the application of the modified valve was not observed. This would be owing to the tapered configuration of the additional rim with 0.1mm width of inflow side.From the data above, the modified polymer valve showed great promise for clinical artificial heart application, and it was also clarified that our prevent fatigue tester could provide comparative durability data of polymer valves.