title: Numerical models of net-structure stents inserted into arteries.
abstract: BACKGROUND
  Restenosis is strongly attributed to stresses caused by stent-artery interactions generated in the artery after balloon angioplasty. Numerical methods are often used to examine the stent-artery mechanical interactions. To overcome the extensive computational requirements demanded by these simulations, simplifications are needed.
  
  
  OBJECTIVE
  We introduce simplified models to calculate the mechanical interactions between net-structured stents and arteries, and discuss their validity and implications.
  
  
  METHODS
  2D simplified numerical models are suggested, which allow cost effective assessment of arterial stresses and the potential damage factor (DF). In these models, several contact problems were solved for arteries with hyper elastic mechanical properties. Stresses were calculated for a large range of cases and for different numerical model types. The effects of model simplifications, oversizing mismatch and stenosis rate and length and symmetry on the resulting stresses were analyzed.
  
  
  CONCLUSIONS
  Results obtained from planar 2D models were found in good agreement with results obtained from complex 3D models for cases with axisymmetric constant or varying stenosis. This high correlation between the results of 3D cases with varying stenosis and the more simple 2D cases can be used as a simplified and convenient tool for calculating the arterial wall stresses in complex cases. Maximal stresses obtained by the 2D model with an asymmetric stenosis are lower than the maximal stresses obtained in the axisymmetric case with the same stenosis percentage. Therefore, axisymmetric models may provide the worst-case estimation values for a stent of interest.
authors.affiliation: Department of Mechanical Engineering and Mechatronics, Ariel University, Israel. Electronic address: mosheb@ariel.ac.il.
authors.forename: Moshe
authors.initials: M
authors.lastname: Brand
authors.affiliation: Department of Mechanical Engineering and Mechatronics, Ariel University, Israel.
authors.forename: Idit
authors.initials: I
authors.lastname: Avrahami
authors.affiliation: Department of Biomedical Engineering, Tel Aviv University, Israel.
authors.forename: Shmuel
authors.initials: S
authors.lastname: Einav
authors.affiliation: School of Mechanical Engineering, Tel Aviv University, Israel.
authors.forename: Michael
authors.initials: M
authors.lastname: Ryvkin
mesh_terms: D001158:Arteries / Q000473:pathology*; D006801:Humans; D015233:Models, Statistical; D015607:Stents; D014652:Vascular Diseases / Q000628:therapy*
keywords: Damage factor; Hyper elastic mechanical properties; Numerical models; Restenosis; Stent–artery interaction