Objectives: Experimental evidence suggests that structuralchanges to the arterial adventitia may be a key vascular determinant of earlyarterial stiffening, although this has not been directly studied. Accordingly,we hypothesized that in young children, in whom this relationship would not bealtered by atheroma, carotid extramedial thickness (EMT), a measure thatincorporates the thickness of the arterial adventitia, perivascular tissues andthe internal jugular venous wall, would be associated with localized arterialstiffness of the same arterial region.
Methods: We studied 248 healthy prepubescent children (aged8 years). Carotid diameter and carotid EMT were measured by high-resolutionultrasound. Carotid blood pressure was derived from brachial blood pressure andcarotid tonometry. Three measures of localized arterial stiffness (β stiffnessindex, distensibility coefficient and incremental modulus of elasticity) werecalculated for the common carotid artery. Results were adjusted for heart rateand DBP, two important hemodynamic determinants of arterial stiffness.
Results: Carotid EMT was associated with all three measuresof arterial stiffness (β stiffness index: standardized β = 0.121, P = 0.03;distensibility coefficient: standardized β = -0.121, P = 0.05; incrementalmodulus of elasticity: standardized β = 0.140, P = 0.02). These associationsremained significant after adjustment for potential confounders such as sex,height, waist circumference, BMI and body surface area.
Conclusion: Carotid EMT is associated with the stiffness ofthe same arterial segment in children, suggesting that the arterial adventitiamay be involved in early changes in arterial stiffness during childhood.