Abstract:
Introduction: The compliance of the distal arteries depends on their vasoconstrictor tone and distensibility and is sensitive to endothelial function and aging. C2, a component of the Windkessel model, is a measure of distal arterial compliance, and establishes
the magnitude of the pressure rise during early diastole. It is calculated from the diastolic portion of the radial pulse wave
using sophisticated analyses. C2 is used as a cardiovascular risk indicator since it decreases with aging, high blood pressure, and
diabetes. Here, we propose an alternative method to assess the distal arteries distensibility by measuring the amplitude of the
oscillation that occurs at the beginning of diastole.
Methods: Peripheral pulse wave was evaluated noninvasively by applanation tonometry in 511 individuals (264 women) aged
between 13 and 70 years. Diastolic amplitude (DA) was measured as the peak-to-peak amplitude of the diastolic oscillation. Radial
augmentation index (RAIx) and pulse wave velocity (PWV) were also calculated.
Results: DA decreased approximately 2% per decade of life between 16 and 70 years from 19% to 7%, and was higher in men than in
women (p<0.0001). Linear regression analysis identified RAIx as the strongest predictor of AD (p<0.0001), followed by age and
height. Sex modified the age-related decrease in DA (p< 0.001). By applying the method to measure DA from previously published
data, we found a strong linear correlation with C2.
Conclusion: DA decreased linearly with age in a reciprocal manner to the increase in radial augmentation index, was greater in men
than women, and was independent of blood pressure and heart rate, as previously reported for C2. We propose that measuring
DA could provide an alternative index to evaluate distal arterial compliance and aging.
