Abstract
Introduction: Coronary stent fracture is recognized as causes of restenosis or thrombosis. We conducted finite element analysis (FEA) of coronary stent to predict fatigue failure under cyclic bend loading. Methods: Matched with manufacturing steps of coronary stent, a stent with a diameter, length and thickness of 1.8mm, 18mm, and 81μm was modeled. The stent was crimped on a balloon by applying enforced displacement until the outer diameter became 1.0mm. Next, the stent was deployed into a bended coronary artery model with an angulation of 125 degrees. Then, cyclic bend from 125 degrees to 105 degrees was applied to the stent. Results and Discussions: FEA of alternating stress, mean stress, and fatigue safety factor showed that there were nodes in unsafe zone in Goodman diagram. FEA suggested a threshold of cyclic bend angulation of the coronary stent on fatigue failure. Fracture locations observed in the cyclic-bend accelerated durability tests was consistent with the nodes of the stents which exceeded fatigue safety factor of 1. Conclusion: The comparison between FEA and accelerated durability tests indicated that FEA was useful to predict fatigue failure of the coronary stent.layer and gas layer.
