Influence of body height on aortic systolic pressure augmentation and wave reflection in childhood

Abstract

The enhanced wave reflection in small children is a well-known phenomenon. It is explained on the basis of differences in the body height and the timing of wave reflection. This hypothesis still has not been proved directly. The aim of our study was to determine the reference values of aortic augmentation index (Aix(ao)) and the simultaneously measured return time of the systolic pulse wave (RT) in relation to the body height to test this hypothesis. Aix(ao) and RT were measured by Arteriograph in a healthy population aged 3-18 years (n = 4619, 2489 males). The Aix(ao) decreased with increasing age in boys from 18.6 ± 8.4% to 4.7 ± 4.3% and in girls from 22.3 ± 9.2% to 8.1 ± 5.1%, whereas the RT increased from 115.5 ± 16.3 ms to 166.7 ± 20.8 ms in boys and from 106.7 ± 21.9 ms to 158.1 ± 15.5 ms in girls. These changes were constant during childhood, but they slowed down after the onset of puberty. Because aortic pulse wave velocity (PWV(ao)) measured in the same population was unchanged during childhood, the increase of RT can only be explained by the increase of aortic length due to growth. In the puberty PWV(ao) starts increasing indicating that RT (Aix(ao)) does not follow the increase (decrease) of aortic length proportionally.

The associations of cardiorespiratory fitness, adiposity and sports participation with arterial stiffness in youth with chronic diseases or physical disabilities

“…Age and sex-specific SDS norm values for PWVao and AIX% were calculated based on the data of over 4500 Caucasian children and adolescents. 29,30 A higher PWVao indicates higher aortic stiffness and a higher AIX% indicates higher peripheral arterial tone.…”

“…29,30 The area under the curve (AUC) is considered a measure of the effectiveness of the predictor variable to identify correctly children and adolescents at or above +1 SD of PWVao and AIX% (sensitivity) and to identify correctly participants (specificity) below +1 SD of PWVao and AIX%. An AUC of 1 represents the ability to identify perfectly children and adolescents at or above +1 SD of PWVao and AIX% from other participants, whereas an AUC of 0.5 indicates no greater predictive ability than chance alone.…”

Utility of arterial stiffness assessment in children

“…Augmentation index is higher in females indicative of the gender-specific aortic wall characteristics after puberty. 30 Part II…”

Peak oxygen uptake, ventilatory threshold, and arterial stiffness in adolescents

“…AIx% was computed from the pressure difference between the first (P1) and second (P2) wave in relation to the pulse pressure by the formula (AIx% = [(P2-P1)/pulse pressure] x 100. Age and sex-specific standard deviation scores (SDS) for PWVao and AIx% were calculated based on the data of over 4500 Caucasian children and adolescents (Hidvégi et al 2012(Hidvégi et al , 2015. We have previously reported a good shortterm reproducibility for PWVao (intraclass correlation coefficient=0.90, coefficient of variation=3.7%) and moderate reproducibility for AIx% (intraclass correlation coefficient=0.88, coefficient of variation=29.1%) in adolescents (Haapala et al 2018).…”