title: Selection of helical braided flow diverter stents based on hemodynamic performance and mechanical properties.
abstract: BACKGROUND
  Although flow diversion is a promising procedure for the treatment of aneurysms, complications have been reported and it remains poorly understood. The occurrence of adverse outcomes is known to depend on both the mechanical properties and flow reduction effects of the flow diverter stent.
  
  
  OBJECTIVE
  To clarify the possibility of designing a flow diverter stent considering both hemodynamic performance and mechanical properties.
  
  
  METHODS
  Computational fluid dynamics (CFD) simulations were conducted based on an ideal aneurysm model with flow diverters. Structural analyses of two flow diverter models exhibiting similar flow reduction effects were performed, and the radial stiffness and longitudinal flexibility were compared.
  
  
  RESULTS
  In CFD simulations, two stents-Pore2-d35 (26.77° weave angle when fully expanded, 35 μm wire thickness) and Pore3-d50 (36.65°, 50 μm respectively)-demonstrated similar flow reduction rates (68.5% spatial-averaged velocity reduction rate, 85.0% area-averaged wall shear stress reduction rate for Pore2-d35, and 68.6%, 85.4%, respectively, for Pore3-d50). However, Pore3-d50 exhibited greater radial stiffness than Pore2-d35 (40.0 vs 21.0 mN/m at a 3.5 mm outer diameter) and less longitudinal flexibility (0.903 vs 0.104 N·mm bending moments at 90°). These measurements indicate that changing the wire thickness and weave angle allows adjustment of the mechanical properties while maintaining the same degree of flow reduction effects.
  
  
  CONCLUSIONS
  The combination of CFD and structural analysis can provide promising solutions for an optimized stent. Stents exhibiting different mechanical properties but the same flow reduction effects could be designed by varying both the weave angle and wire thickness.
authors.affiliation: Graduate School of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Graduate School of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan.|Department of Neurosurgery, Jikei University School of Medicine, Tokyo, Japan.|Department of Innovation for Medical Information Technology, Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Takao
authors.affiliation: Graduate School of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan.
authors.forename: Soichiro
authors.initials: S
authors.lastname: Fujimura
authors.affiliation: Department of Neurosurgery, Jikei University School of Medicine, Tokyo, Japan.|Siemens Healthcare K.K., Tokyo, Japan.
authors.forename: Chihebeddine
authors.initials: C
authors.lastname: Dahmani
authors.affiliation: Department of Neurosurgery, Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Ishibashi
authors.affiliation: Department of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan.
authors.forename: Hiroya
authors.initials: H
authors.lastname: Mamori
authors.affiliation: Department of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Fukushima
authors.affiliation: Department of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Yamamoto
authors.affiliation: Department of Neurosurgery, Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Murayama
mesh_terms: D001783:Blood Flow Velocity / Q000502:physiology*; D003198:Computer Simulation; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D057446:Hydrodynamics; D002532:Intracranial Aneurysm / Q000503:physiopathology / Q000628:therapy; D015607:Stents; D013314:Stress, Mechanical; D013526:Surgical Mesh
keywords: Aneurysm; Blood Flow; Device; Flow Diverter; Stent