Age-related Upper Limb Vascular System Windkessel Model using Photoplethysmography

Arterial stiffness is known to be affected by aging, leading to changes in peripheral pulse propagation speed and shape. In this paper, the heart-finger segment of the upper- limb vascular system of six subjects in two age-groups (below 30 and above 55 years) is modeled using a modified Windkessel model. Actual left-ventricle pressure (LVP) data has been used as the input to the model. Circuit simulation results show a significantly higher amplitude for the dicrotic notch and a lower second peak in younger subjects. Among the older subjects, there was a gradual disappearance of dicrotic notch while the second peak appeared later. Comparison of the characteristics of the model output with measured peripheral pulse shows a good degree of conformity with the actual pulse signal. The parameters in the Windkessel model provide a simple, noninvasive means for studying changes in the elastic properties of the vascular system, depending on the age and potentially state of health.