What's the Fate of Long-term Implanted Zigzag Shaped Stent-grafts: A Question Raised from the in vitro Simulation Test

摘要

Though the zigzag shaped stent-graft is the key device to treat AAAs with the effective method of Transluminally Placed Endovascular Grafts,it has been reported that some devices presented different fatigue problems during explantation.Thus,it is necessary to investigate the fatigue properties of zigzag shaped stent-grafts in vitro under the simulation condition.This paper aimed to test and evaluate the fatigue property of zigzag shaped stent-grafts in vitro with the instrument of SG twist and buckling fatigue simulation providing a dynamic environment.Two zigzag shaped stent-grafts presented the holes on the graft,the broken of sutures and the scratches on the stents after the twist and buckling fatigue simulation test proceeded 8 and 7 hours respectively.The sharp tip of zigzag shaped stents and the tightly stitching tension of sutures mainly contributed to the failure of devices.In addition,the scratches on the Nitinol stents caused by the tight sutures may destroy the TiO2 on the surface layer and expose the inner toxic layer with Nickel ions.Thus,there still left a lot to improve the fatigue property of zigzag shaped stent-grafts in order to enhance the biodurability of devices and relieve the pain of patients.