Expanded Diameter of Coronary Metal Stent: Simulation and Experiment

Information of expanded-diameter of stent provided by manufacturer is important for cardiologists and required during percutaneous coronary intervention (PCI) procedure. The expanded diameter of the stent is experimentally obtained by inflating a balloon catheter at a certain pressure, from normal to burst pressures. For stent manufacturer view in which stent mass production was taken place, testing of huge number of stent by experiment would be costly and it would be less expensive by simulation. The aims of the present work therefore would investigate the correlation of inflated pressures to expanded diameters which would be done by simulation or numerical and experiment. Numerical work has been performed by software ABAQUS and experiment has been done by using hydraulic inflated device. Stent model was open cell type made of stainless steel 316. The inflated pressures of 0.8, 1.2 and 1.6 MPa were applied to both numerical and experiment works. Results on numerical and experimental show that expanded diameter increases proportionally to the increase of inflated pressures. However, at the inflated pressure of 0.8 MPa, there was significant gap between the outer diameter obtained by numerical and experiment. Numerical result depicted over estimate to that of experiment. The inflated pressure window for having inflated diameter of 4mm to 4.5mm was 0.8 to 1.1 MPa. Although, numerically the stent has been fractured due to the von Mises stress was already over the ultimate stress of the material, in fact there was no evident depicted by SEM image.