Effects of strut numbers on biomechanical properties of Z-shaped stent-grafts / 医用生物力学

ABSTRACT

Objective To analyze the influence from strut numbers on biomechanical properties of Z-shaped stent-grafts, especially on their radial support performance and flexibility, so as to provide theoretical support for the design and clinical selection of Z-shaped stent-grafts. Methods Z-shaped stent-grafts with 5, 8, 10, 12 struts were established by finite element method to simulate the process of compression and bending behavior. Radial displacements were applied on surface of the stent-graft and opposite rotations were applied around the z-axis, until a bending angle of 40°was reached. Then parameters such as stent stress, radial support force, strains in graft, cross-section deflection, bending torque were extracted to evaluate the performance of different stent-grafts. Results Compared with stent-grafts with more strut numbers, 5-strut stent-graft showed a better radial support performance with the maximum radial force during compression, and it also generated the smallest 68 N•mm torque and 67.5% cross-section deflection. The tensile strain in graft of 5-strut stent-graft during the process of bending was relatively smaller. Conclusions The struts number of Z-shaped stent-grafts has a significant influence on biomechanical properties of the stent-grafts. Especially the Z-shaped stent-graft with relatively fewer strut numbers shows an advantage in evaluating radial support performance and flexibility such as the bending torque and the cross-section deflection, and is more suitable to be anchored and fit to the tortuous blood vessel, which will play a positive role in decreasing the complication such as endoleaks and thrombosis. The research findings can guide structure design of Z-shaped stent-grafts and the operation to make an optimal selection.