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 stentgrafts,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 stentgrafts.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 strut 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 optimal selection for surgery.