Estimation of force on vascular wall caused by insertion of self-expanding stents

Stent placement is a minimally invasive procedure that has received considerable attention as a treatment option for vascular stenotic lesions associated with coronary atherosclerosis. However, the severe problem of in-stent restenosis has recently begun to occur in blood vessels in which long-term placement of stents has occurred. In-stent restenosis results from the increase in neointimal hyperplasia caused by the stimulus of the force on the vascular wall. In the present study, methods are proposed to compute the contact force and straightening force on a vascular wall. The force on the vascular wall is calculated using these methods. As an example, the force on the vascular wall created by the insertion of the stent into the carotid artery is calculated, and the concentration of the force at both ends of the stent is confirmed. Guidelines are presented to modify the stent shape based in order to remove this force concentration which may provoke the neointimal hyperplasia. The methods described in the present paper are easily applied to the shape design of stents and will be an effective tool for improving the stent shape.