title: Non-invasive assessment of endothelial function: which technique?
abstract: OBJECTIVE
  The purpose of this study was to compare 3 non-invasive techniques for assessment of endothelial function in adults and children and evaluate their utility in acute inflammation.
  
  
  BACKGROUND
  Endothelial dysfunction is a key early event in pre-clinical atherosclerosis. Flow-mediated dilation (FMD), although the established technique, is expensive and technically demanding. Measurements of vascular responses to inhaled salbutamol by pulse wave analysis (PWA) or pulse contour analysis (PCA) are potential alternatives.
  
  
  METHODS
  Sixteen adults (mean age 28 years, range 18 to 39) and 16 children (mean age 13 years, range 7 to 17) underwent concurrent vascular function testing on 2 occasions with ultrasound, PWA, and PCA. Eighteen men were also studied before and after typhoid vaccination.
  
  
  RESULTS
  Reproducibility of FMD was high in adults and children (coefficient of variation [CV] = 7.1 and 6.3, respectively). Salbutamol responses were more variable with PWA (adults CV = 11.5, children CV = 17.1) and PCA particularly in children (adults CV = 18.2, children CV = 36.3). Flow-mediated dilation (p < 0.001) and PWA with salbutamol (p = 0.03) responses fell after typhoid vaccination, and PCA (p = 0.7) was unchanged.
  
  
  CONCLUSIONS
  Vascular dysfunction during acute inflammation can be measured by FMD and by PWA with salbutamol. Flow-mediated dilation is less variable than PWA. Variability of PCA makes this technique currently unsuited to serial measures of endothelial function in children. Flow-mediated dilation remains the most reproducible method.
authors.affiliation: Institute of Child Health, University College London, London, United Kingdom. A.Donald@ich.ucl.ac.uk
authors.forename: Ann E
authors.initials: AE
authors.lastname: Donald
authors.forename: Marietta
authors.initials: M
authors.lastname: Charakida
authors.forename: Tim J
authors.initials: TJ
authors.lastname: Cole
authors.forename: Peter
authors.initials: P
authors.lastname: Friberg
authors.forename: Phil J
authors.initials: PJ
authors.lastname: Chowienczyk
authors.forename: Sandrine C
authors.initials: SC
authors.lastname: Millasseau
authors.forename: John E
authors.initials: JE
authors.lastname: Deanfield
authors.forename: Julian P
authors.initials: JP
authors.lastname: Halcox
mesh_terms: D000293:Adolescent; D000328:Adult; D001783:Blood Flow Velocity / Q000187:drug effects / Q000502:physiology; D001916:Brachial Artery / Q000187:drug effects / Q000502:physiology; D002648:Child; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D005996:Nitroglycerin / Q000494:pharmacology; D011673:Pulsatile Flow / Q000502:physiology*; D014436:Typhoid-Paratyphoid Vaccines / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology
chemical_list: D014436:Typhoid-Paratyphoid Vaccines; D005996:Nitroglycerin