title: Carotid extramedial thickness is associated with local arterial stiffness in children.
abstract: OBJECTIVE
  Experimental evidence suggests that structural changes to the arterial adventitia may be a key vascular determinant of early arterial stiffening, although this has not been directly studied. Accordingly, we hypothesized that in young children, in whom this relationship would not be altered by atheroma, carotid extramedial thickness (EMT), a measure that incorporates the thickness of the arterial adventitia, perivascular tissues and the internal jugular venous wall, would be associated with localized arterial stiffness of the same arterial region.
  
  
  METHODS
  We studied 248 healthy prepubescent children (aged 8 years). Carotid diameter and carotid EMT were measured by high-resolution ultrasound. Carotid blood pressure was derived from brachial blood pressure and carotid tonometry. Three measures of localized arterial stiffness (β stiffness index, distensibility coefficient and incremental modulus of elasticity) were calculated for the common carotid artery. Results were adjusted for heart rate and DBP, two important hemodynamic determinants of arterial stiffness.
  
  
  RESULTS
  Carotid EMT was associated with all three measures of arterial stiffness (β stiffness index: standardized β = 0.121, P = 0.03; distensibility coefficient: standardized β = -0.121, P = 0.05; incremental modulus of elasticity: standardized β = 0.140, P = 0.02). These associations remained significant after adjustment for potential confounders such as sex, height, waist circumference, BMI and body surface area.
  
  
  CONCLUSIONS
  Carotid EMT is associated with the stiffness of the same arterial segment in children, suggesting that the arterial adventitia may be involved in early changes in arterial stiffness during childhood.
authors.affiliation: aSydney Medical School bBoden Institute of Obesity, Nutrition, Exercise and Eating Disorders, University of Sydney cDepartment of Cardiology, Royal Prince Alfred Hospital, Sydney dThe Heart Centre for Children, The Children's Hospital at Westmead, Westmead, New South Wales eSchool of Public Health fWoolcock Institute of Medical Research, University of Sydney gSydney Local Health District, Sydney, New South Wales, Australia.
authors.forename: Tommy Y
authors.initials: TY
authors.lastname: Cai
authors.forename: Tim R
authors.initials: TR
authors.lastname: Sullivan
authors.forename: Julian G
authors.initials: JG
authors.lastname: Ayer
authors.forename: Jason A
authors.initials: JA
authors.lastname: Harmer
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Leeder
authors.forename: Brett G
authors.initials: BG
authors.lastname: Toelle
authors.forename: Guy B
authors.initials: GB
authors.lastname: Marks
authors.forename: David S
authors.initials: DS
authors.lastname: Celermajer
authors.forename: Michael R
authors.initials: MR
authors.lastname: Skilton
mesh_terms: D063194:Adventitia / Q000000981:diagnostic imaging*; D062186:Arterial Pressure; D001916:Brachial Artery; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D002648:Child; D055119:Elastic Modulus / Q000502:physiology; D005260:Female; D006801:Humans; D007601:Jugular Veins / Q000000981:diagnostic imaging; D008297:Male; D014463:Ultrasonography; D059289:Vascular Stiffness / Q000502:physiology*