title: Alteration of intra-aneurysmal hemodynamics for flow diversion using enterprise and vision stents.
abstract: OBJECTIVE
  Flow diversion is a novel concept for intracranial aneurysm treatment. The recently developed Enterprise Vascular Reconstruction Device (Codman Neurovascular, Raynham MA) provides easy delivery and repositioning. Although designed specifically for restraining coils within an aneurysm, this stent has theoretical effects on modifying flow dynamics, which have not been studied. The goal of this study was to quantify the effect of single and multiple self-expanding Enterprise stents alone or in combination with balloon-mounted stents on aneurysm hemodynamics using computational fluid dynamics (CFD).
  
  
  METHODS
  The geometry of a wide-necked, saccular, basilar trunk aneurysm was reconstructed from computed tomographic angiography images. Various combinations of 1-3 stents were "virtually" conformed to fit into the vessel lumen and placed across the aneurysm orifice. CFD analysis was performed to calculate hemodynamic parameters considered important in aneurysm pathogenesis and thrombosis for each model.
  
  
  RESULTS
  The complex aneurysmal flow pattern was suppressed by stenting. Stent placement lowered average flow velocity in the aneurysm; further reduction was achieved by additional stent deployment. Aneurysmal flow turnover time, an indicator of stasis, was increased to 114-117% for single-stent, 127-128% for double-stent, and 141% for triple-stent deployment. Furthermore, aneurysmal wall shear stress (WSS) decreased with increasing number of deployed stents.
  
  
  CONCLUSIONS
  This is the first study analyzing flow modifications associated with placement of Enterprise stents for aneurysm occlusion. Placement of 2-3 stents significantly reduced intra-aneurysmal hemodynamic activities, thereby increasing the likelihood of inducing aneurysm thrombotic occlusion.
authors.affiliation: Toshiba Stroke Research Center, University at Buffalo, State University of New York, Buffalo, NY, USA.
authors.forename: Markus
authors.initials: M
authors.lastname: Tremmel
authors.forename: Jianping
authors.initials: J
authors.lastname: Xiang
authors.forename: Sabareesh K
authors.initials: SK
authors.lastname: Natarajan
authors.forename: L Nelson
authors.initials: LN
authors.lastname: Hopkins
authors.forename: Adnan H
authors.initials: AH
authors.lastname: Siddiqui
authors.forename: Elad I
authors.initials: EI
authors.lastname: Levy
authors.forename: Hui
authors.initials: H
authors.lastname: Meng
mesh_terms: D002533:Cerebral Angiography; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D002532:Intracranial Aneurysm / Q000503:physiopathology* / Q000601:surgery*; D019635:Neurosurgical Procedures; D015607:Stents