Performance of a nitinol honeycomb stent for the management of atherosclerotic aortic plaque: Crimping, sealing, and fluid-structure interaction analysis

Abstract

We present the results of a computational study to investigate the performance of a nitinol honeycomb stent used in the management of an aortic atherosclerotic plaque with 70% stenosis. Such is considered severe and is associated with a higher risk of cardiovascular death. Traditionally, plaque size, composition, shape, and location are thought as important factors in determining the potential for the plaque to rupture (aka plaque vulnerability). The study looks at two plaque shapes and two plaque compositions. The stent used in the simulations is our own design. It compresses and expands due to nitinol's superelastic property. The human aorta is represented by the Gasser-Ogden-Holzapfel (GOH) model, a sophisticated hyperelastic model which accounts for the dispersion of fibers present in the tissues. We proceed to investigate how the stent-aorta-plaque structure behaves under a physiological blood flow. Results indicate that the stent as designed can sustain realistic blood flow conditions and that hypocellular plaques are more prone to rupture, in agreement with results published in the literature. It also shows that neither plaque composition nor shape affect the wall shear stress (WSS). This study can be useful to surgeons to identify regions of stenotic aorta subjected to high stress, to select the appropriate stent diameter for aortae with plaques with various compositions and plaque shapes, and to decide on the optimal site for stent implantation.