Mechanical evaluation of the diaphragm in pneumatically-driven left ventricular assist devices by FEM analysis

Pneumatically-driven left ventricular assist devices (LVADs) are widely used because they are lower in cost and simpler in operability in comparison with mechanically-driven devices. However, some problems such as the damage of their diaphragms in the devices have been pointed out. In this study, an evaluation program including FEM analysis, in which the NIPRO-LVAD is selected as a sample of a pneumatically-driven LVAD, was developed. The relation between the transmural pressure of the diaphragm and the volume in the blood chamber was approximated by that numerically simulated by the FEM program. In addition, stress and strain in the diaphragm also can be calculated at the same time when the program is executed to determine the deformation of the diaphragm. The program is supposed to be useful in cases for the designing and redesigning of pneumatically-driven pumps with diaphragms.