title: Peak shear and peak flow mediated dilation: a time-course relationship.
abstract: OBJECTIVE
  To explore the temporal relationship between brachial artery peak shear stress (Shear) and flow-mediated dilation (FMD) in children and adults.
  
  
  METHODS
  Shear and brachial artery diameter were tracked following reactive hyperemia in 122 children and 350 adults using sonographic imaging.
  
  
  RESULTS
  Peak Shear, Shear area under the curve (Shear(AUC)), and Peak FMD were significantly larger in children than in adults. The time to peak Shear (Shear(TTP)) and time to peak FMD (FMD(TTP)) were significantly lower in children, while there was no significant difference in time from Shear(TTP) to FMD(TTP) between children and adults.
  
  
  CONCLUSIONS
  Children have a lower shear stimulus and FMD response than adults, but the time interval separating these events is similar. These differences could be due to changes in vascular dynamics with age, including reduced smooth muscle cell responsiveness and other factors. Despite differences in timing, the interval from peak Shear to peak FMD was similar in children and adults.
authors.affiliation: Laboratory of Integrative Human Physiology, School of Kinesiology, University of Minnesota, Minneapolis, MN, 55455.
authors.forename: Nicholas G
authors.initials: NG
authors.lastname: Evanoff
authors.affiliation: Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN, 55455.|Department of Medicine, University of Minnesota Medical School, Minneapolis, MN, 55455.
authors.forename: Aaron S
authors.initials: AS
authors.lastname: Kelly
authors.affiliation: Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN, 55455.
authors.forename: Julia
authors.initials: J
authors.lastname: Steinberger
authors.affiliation: Laboratory of Integrative Human Physiology, School of Kinesiology, University of Minnesota, Minneapolis, MN, 55455.|Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN, 55455.
authors.forename: Donald R
authors.initials: DR
authors.lastname: Dengel
mesh_terms: D000293:Adolescent; D000328:Adult; D001783:Blood Flow Velocity; D001916:Brachial Artery / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D002648:Child; D005260:Female; D006801:Humans; D006940:Hyperemia / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D012039:Regional Blood Flow; D013314:Stress, Mechanical; D013997:Time Factors; D018608:Ultrasonography, Doppler / Q000379:methods*
keywords: adults; children; reactive hyperemia; shear stress; time to peak; ultrasound