title: Biomechanical responses after Wingspan Stent deployment in swine ascending pharyngeal artery.
abstract: OBJECTIVE
  Symptomatic intracranial atherosclerotic stenosis is associated with a high rate of recurrent stroke. Endovascular angioplasty and stenting using the Wingspan(TM) Stent (Stryker) has been used for treatment of this disorder. However, a recent randomized trial  (SAMMPRIS Clinical Trial) reported that it was inferior to aggressive medical management. To explore the cause of stroke complications after treatment with the Wingspan Stent, we simulated the biomechanical responses in a swine ascending pharyngeal artery (APA) using the finite element method.
  
  
  METHODS
  A Wingspan Stent was deployed in a swine APA, and simulated stress distributions including radial, circumferential, and wall shear stress were evaluated. Histopathological analysis of the selected APA was made 28 days post-stenting.
  
  
  RESULTS
  We detected increased radial stress concentration  at distal stent markers with a stent edge and a graded augmentation of radial stress from proximal to distal. There was an impaired wall shear stress near the stent struts and stent markers. Intense neointimal hyperplasia was observed from the middle to distal segment of the stent 28 days  after the procedure.
  
  
  CONCLUSIONS
  This preliminary data suggest that the Wingspan Stent produces increased radial stress distribution with distal segment in a tapering artery. It is possible that the radial stress concentration plays a role in the development of neointimal hyperplasia.
authors: Division of Interventional Neuroradiology, Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-1721, USA. MFujimoto@mednet.ucla.edu
authors: Motoaki
authors: M
authors: Fujimoto
authors: Yasuhiro
authors: Y
authors: Shobayashi
authors: Satoshi
authors: S
authors: Tateshima
authors: Harry V
authors: HV
authors: Vinters
authors: Fernando
authors: F
authors: Viñuela
mesh_terms: D000792:Angiography; D017130:Angioplasty / Q000009:adverse effects / Q000295:instrumentation; D000818:Animals; D001158:Arteries; D001696:Biomechanical Phenomena; D003198:Computer Simulation; D003251:Constriction, Pathologic / Q000209:etiology* / Q000601:surgery; D004195:Disease Models, Animal; D057446:Hydrodynamics; D002537:Intracranial Arteriosclerosis / Q000150:complications* / Q000601:surgery*; D008954:Models, Biological; D010614:Pharynx / Q000098:blood supply; D012984:Software; D015607:Stents / Q000009:adverse effects; D013552:Swine