The Importance of Orthostatic Increase in Pulse Wave Velocity in the Diagnosis of Early Vascular Aging

Abstract

Background/Objectives: Vascular aging can be assessed by arterial stiffness measured through pulse wave velocity (PWV). Increased PWV predicts arterial hypertension, cardiovascular events and all-cause mortality. Detection of early signs of vascular aging remains an unmet problem. To search for the most sensitive markers for the early increase in vascular stiffness in a healthy population. Methods: One-hundred and twenty healthy subjects were divided in three equal age groups: <30 years, 30-45 years and >45 years. Head-up tilt test (HUTT) protocol was applied, providing a standardized hydrostatic column height. PWV at the brachial-ankle artery site (baPWV) was measured using a multichannel sphygmomanometer ABI System 100 PWV in three positions: in the baseline horizontal (supine) position-baPWVb; during the head tilt-up with an individual angle of inclination-baPWVt; and when returning to supine. Results: The most sensitive marker of early stiffness increase in a healthy population is the relative orthostatic increase in baPWV, ΔbaPWV/baPWVb, where ΔbaPWV = baPWVt - baPWVb. The significance of differences in this parameter between the young and elderly groups reached p = 0.000075 and p = 0.000006, respectively. Conclusions: The proposed index ΔbaPWV/baPWVb can be considered as a promising sensitive early biomarker of vascular aging and as a potential effective indicator in cardiovascular prevention. A longitudinal cohort study is needed to confirm this assumption.

Keywords: arterial hypertension; head-up tilt test; orthostatic increase in vascular stiffness; preclinical orthostatic hemodynamic dysregulation; pulse wave velocity; risk-based prevention; vascular aging; vascular stiffness.

Figure 1

Linear regression graphs between age (independent variable) and different indices of vascular stiffness in healthy individuals: basal PWV, baPWVb (A), increase in baPWB after tilt, ΔbaPWV (B), and relative increase in baPWV after tilt, ΔbaPWV/baPWVb (C). Legend: Horizontal axis: age, years. Vertical axis: baPWVb, m/s (A), ΔbaPWV, m/s (B) and ΔbaPWV/baPWVb (C). Red line—regression line in linear model of regression.