Modelling the development of in-stent restenosis: Preliminary results of a structural model

Abstract

Coronary artery diseases are at present commonly treated by minimally invasive treatment such as intravascular stents. However, such treatment is compromised by in-stent restenosis, a re-narrowing of the artery related to the injury of the vessel wall as a result of the local stress caused by the stent struts. The aim of this study is to develop a computational model to represent this tissue growth in a finite element model of a stented coronary artery. A 1/6 symmetry section of a coronary artery was generated within ANSYS Mechanical APDL version 12.0 (ANSYS Inc.). A ‘ghost’ finite element mesh was used to represent the region of the vessel where neointimal growth is expected to occur. The model was used to assess the influence of the initial strain in the neointima on the stress state within the vessel under subsequent pulsatile pressure loading. These results suggest that, if the proliferative response within the neointima is related to local stress, some initial strain must be present during the deposition of the tissue. A validated model has the potential to reduce the occurrence of restenosis through improved understanding of stent/artery interactions.