First-harmonic attenuation of radial pulse waves as a sensitive marker for vascular aging

Accurate assessment of vascular aging and arterial stiffness is essential for early cardiovascular intervention. Traditional pulse wave velocity (PWV) measurements often face limitations in peripheral arteries. This study proposes complex wave velocity derived from the radial pulse as a novel metric for evaluating age-related vascular changes. We performed radial pulse wave analysis on 919 participants (aged 6-92 years). Using a non-invasive pressure transducer, pulse waveforms were recorded and transformed into the frequency domain. A wave propagation model based on the Womersley number was applied to determine the real (X) and imaginary (Y) components of the complex wave speed for the first four harmonics. The first harmonic emerged as the dominant energy contributor with the highest measurement stability. Analysis of the vascular property revealed that the imaginary component (Y₁), representing wave attenuation, decreased significantly with age (p < 0.001), while the real component (X₁, phase velocity) remained relatively stable. This energy redistribution toward lower-order harmonics results in a broader, fuller pulse morphology in older populations. Complex wave velocity, specifically the first-harmonic attenuation (Y₁), serves as a highly sensitive marker for vascular aging. This approach provides a robust, non-invasive method for monitoring arterial health and supports the identification of new vascular biomarkers.