Spectral Analysis of Radial Pulse Wave for Non-Invasive Assessment of Arterial Aging

Abstract

The radial pulse wave (OP) provides a valuable reflection of arterial system dynamics, offering insights into vascular aging. This study aimed to evaluate vascular aging by analyzing the spectral characteristics of the OP and determining the system's resonance frequency and its relationship with age, uti- lizing the four-element Windkessel model, which accounts for distal compli- ance. Pulse wave recordings from 100 healthy males aged 18 to 65 years were analyzed. Fourier analysis was applied to identify the frequency of maximum gain of the Windkessel model, analyzing the specific spectrum of the diastolic oscillation and using Lagrange interpolation for the accurate determination of this frequency. The Diastolic Pressure Augmentation (DPA) was also measured, examining its dependence on harmonics and age. Results indicated that fre- quency of maximum gain remained stable with age, averaging approximately 3.5Hz. Conversely, DPA decreased linearly with age at a rate of 0.11 mmHg by year. The third harmonic was identified as the principal spectral determinant of DPA for normal heart rate. The arterial system's behavior was consistent with an underdamped response, with resonance persisting across all age groups. In conclusion, while the resonance frequency of the arterial system remains con- stant with aging, its gain diminishes due to a reduction in distal compliance. Spectral evaluation of the OP offers a non-invasive, functional indicator for ar- terial aging, complementing traditional assessment methods.