title: Computational fluid dynamics analysis of tandem carotid artery stenoses: Investigation of neurological complications after carotid artery stenting.
abstract: BACKGROUND
  Combined extra- and intracranial carotid artery stenoses, particularly involving multiple lesions, show complex hemodynamic properties and represent a therapeutic dilemma. We used computational fluid dynamics (CFD) to investigate whether insufficient cerebral blood flow (CBF) in a 70-year-old man with tandem stenoses was the cause of aphasia and right hemiparesis after carotid artery stenting (CAS) of the extracranial stenosis.
  
  
  METHODS
  Three-dimensional digital subtraction angiography (3D-DSA) was performed before and after balloon angioplasty and CAS in the patient. The geometrical and rheological conditions of the carotid arteries were determined, and computational meshes were generated from the patient-specific 3D-DSA datasets. CFD analysis was performed, and hemodynamic parameters such as mass flow, pressure, fractional flow reserve, and streamlines were calculated.
  
  
  RESULTS
  Post-CAS simulations showed that the percentage of internal carotid artery mass flow from common carotid artery mass flow increased from 9% to 14% and CBF improved by only 5%.
  
  
  CONCLUSIONS
  CFD analysis suggested that the neurological complications were caused by insufficient CBF rather than embolic events, and in tandem carotid stenoses, CAS for an extracranial lesion alone may not always sufficiently increase CBF. CFD enabled the noninvasive quantitative estimation of the effects of CAS of each stenotic segment on carotid flow.
authors.affiliation: Department of Neurosurgery, The Jikei University School of Medicine, Tokyo, Tokyo, Japan.
authors.forename: Yukinao
authors.initials: Y
authors.lastname: Kambayashi
authors.affiliation: Department of Neurosurgery, The Jikei University School of Medicine, Tokyo, Tokyo, Japan.|Graduate School of Mechanical Engineering, Tokyo University of Science, 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: Kouichi
authors.initials: K
authors.lastname: Shinohara
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.
authors.forename: Sho
authors.initials: S
authors.lastname: Takayama
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, The Jikei University School of Medicine, Tokyo, Tokyo, Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Masuda
authors.affiliation: Department of Neurosurgery, The Jikei University School of Medicine, Tokyo, Tokyo, Japan.
authors.forename: Mituyoshi
authors.initials: M
authors.lastname: Watanabe
authors.affiliation: Department of Neurosurgery, The Jikei University School of Medicine, Tokyo, Tokyo, Japan.
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Department of Neurosurgery, The Jikei University School of Medicine, Tokyo, Tokyo, Japan.|Siemens Healthcare K.K., Tokyo, Japan.
authors.forename: Chihebeddine
authors.initials: C
authors.lastname: Dahmani
authors.affiliation: Department of Neurosurgery, The Jikei University School of Medicine, Tokyo, 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: Makoto
authors.initials: M
authors.lastname: Yamamoto
authors.affiliation: Department of Neurosurgery, The Jikei University School of Medicine, Tokyo, Tokyo, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Murayama
mesh_terms: D000368:Aged; D000800:Angioplasty, Balloon; D001037:Aphasia / Q000209:etiology; D002342:Carotid Artery, External / Q000503:physiopathology / Q000601:surgery*; D002343:Carotid Artery, Internal / Q000503:physiopathology*; D016893:Carotid Stenosis / Q000150:complications / Q000601:surgery*; D002533:Cerebral Angiography; D002560:Cerebrovascular Circulation / Q000502:physiology*; D006439:Hemodynamics; D006801:Humans; D057446:Hydrodynamics; D021621:Imaging, Three-Dimensional; D008297:Male; D010291:Paresis / Q000209:etiology; D015607:Stents
keywords: Carotid artery stenting; carotid stenosis; cerebral blood flow; computational fluid dynamics; neurological complication