Age-associated changes in arterial elastic properties in children

Age-associated changes in pulsatile components of the arterial system in normal children have not previously been studied. The purpose of the present study was to establish reference ranges for age-associated changes in arterial pulsatile properties in children. Arterial compliance (C-A()) and stiffness of the proximal aorta were estimated from data obtained by cardiac catheterisation in 112 paediatric patients (age range, 6 months to 20 years) who were considered to have normal systemic vascular beds. C-A was calculated by the area method, using ascending aortic pressure tracings. Aortic wall stiffness was evaluated using the pressurestrain elastic modulus (Ep). CA significantly increased with age (C-A = 0.065 x age + 0.86, r = 0.71, P < 0.001). However, the value of C-A/BSA, which represents normalisation of C-A to body surface area (BSA) (to eliminate factors associated with development of arterial size), significantly decreased with age and declined fastest during the first several years of life, suggesting an increase in arterial wall stiffness with increasing age in children. Ep also significantly increased with age (Ep = 9.8 x age + 177, r = 0.50, P < 0.001). Conclusion: these findings suggest that both peripheral and proximal arterial wall distensibility in children decline after birth, although total arterial buffering capacity increases. The present results provide the first quantification of in vivo age-associated changes in arterial elastic properties in children, and are potentially useful as a reference for future studies of patients with diseases that involve the vascular system.