title: Increased Inlet Blood Flow Velocity Predicts Low Wall Shear Stress in the Cephalic Arch of Patients with Brachiocephalic Fistula Access.
abstract: BACKGROUND
  An autogenous arteriovenous fistula is the optimal vascular access for hemodialysis. In the case of brachiocephalic fistula, cephalic arch stenosis commonly develops leading to access failure. We have hypothesized that a contribution to fistula failure is low wall shear stress resulting from post-fistula creation hemodynamic changes that occur in the cephalic arch.
  
  
  METHODS
  Twenty-two subjects with advanced renal failure had brachiocephalic fistulae placed. The following procedures were performed at mapping (pre-operative) and at fistula maturation (8-32 weeks post-operative): venogram, Doppler to measure venous blood flow velocity, and whole blood viscosity. Geometric and computational modeling was performed to determine wall shear stress and other geometric parameters. The relationship between hemodynamic parameters and clinical findings was examined using univariate analysis and linear regression.
  
  
  RESULTS
  The percent low wall shear stress was linearly related to the increase in blood flow velocity (p < 0.01). This relationship was more significant in non-diabetic patients (p < 0.01) than diabetic patients. The change in global measures of arch curvature and asymmetry also evolve with time to maturation (p < 0.05).
  
  
  CONCLUSIONS
  The curvature and hemodynamic changes during fistula maturation increase the percentage of low wall shear stress regions within the cephalic arch. Low wall shear stress may contribute to subsequent neointimal hyperplasia and resultant cephalic arch stenosis. If this hypothesis remains tenable with further studies, ways of protecting the arch through control of blood flow velocity may need to be developed.
authors.affiliation: Department of Medicine, Nephrology Section, The University of Chicago, Chicago, IL, United States of America.
authors.forename: Mary
authors.identifier: http://orcid.org/0000-0002-2524-6432
authors.initials: M
authors.lastname: Hammes
authors.affiliation: Department of Mechanical, Materials and Aerospace Engineering, Illinois Institute of Technology, Chicago, IL, United States of America.
authors.forename: Michael
authors.initials: M
authors.lastname: Boghosian
authors.affiliation: Department of Mechanical, Materials and Aerospace Engineering, Illinois Institute of Technology, Chicago, IL, United States of America.
authors.forename: Kevin
authors.initials: K
authors.lastname: Cassel
authors.affiliation: Department of Public Health Sciences, Biostatistics Laboratory, The University of Chicago, Chicago, IL, United States of America.
authors.forename: Sydeaka
authors.initials: S
authors.lastname: Watson
authors.affiliation: Department of Radiology, The University of Chicago, Chicago, IL, United States of America.
authors.forename: Brian
authors.initials: B
authors.lastname: Funaki
authors.affiliation: Department of Radiology, The University of Chicago, Chicago, IL, United States of America.
authors.forename: Taral
authors.initials: T
authors.lastname: Doshi
authors.affiliation: Department of Mechanical, Materials and Aerospace Engineering, Illinois Institute of Technology, Chicago, IL, United States of America.
authors.forename: S M Javid
authors.initials: SM
authors.lastname: Mahmoudzadeh Akherat
authors.affiliation: Department of Medicine, Nephrology Section, The University of Chicago, Chicago, IL, United States of America.
authors.forename: Jane
authors.initials: J
authors.lastname: Hines
authors.affiliation: Department of Medicine, Nephrology Section, The University of Chicago, Chicago, IL, United States of America.
authors.forename: Fredric
authors.initials: F
authors.lastname: Coe
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001166:Arteriovenous Shunt, Surgical; D001783:Blood Flow Velocity / Q000502:physiology*; D016122:Brachiocephalic Trunk / Q000503:physiopathology* / Q000601:surgery; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013314:Stress, Mechanical; D055815:Young Adult