Association of Windkessel Model Parameters with Local and Regional Aortic Stiffness Indices

Windkessel model assesses the buffering function of large arteries and has the potential to describe the global characteristics of the vasculature. In this work, we investigate the association between the Windkessel model parameters and the existing, clinically significant local, global stiffness indices and blood pulse indices. A three-element Windkessel model was used to estimate the ventricular-arterial coupling, arterial compliance, and peripheral resistance from the pressure and flow waveforms at the aorta. The study was performed on 213 healthy virtual subjects (age: 44 boldsymbol{pm15} years). Total arterial compliance had a significant individual correlation boldsymbol{(mathrm{R} > 0.50, mathrm{p}} boldsymbol{ < 0.05)} with local and regional stiffness indices whereas characteristic impedance had a correlation of boldsymbol{(mathrm{R} > 0.22, mathrm{p} < 0.05)} with stiffness indices. Total peripheral resistance, on the other hand, did not show a significant correlation with vascular stiffness. Multivariate regression gave a better independent correlation between the Windkessel model parameters and vascular indices (Adjusted boldsymbol{mathrm{R} > 0.88, mathrm{p} < 0.05)} with total peripheral resistance showing the highest correlation (Adjusted boldsymbol{mathrm{R}=0.95, mathrm{p} < 0.05)} and total arterial compliance showing with least correlation ( Adjusted boldsymbol{mathrm{R}=0.88, mathrm{p} < 0.05)}. The significance in the association of Windkessel markers with stiffness indices highlights the potential of Windkessel model parameters in being a prognostic marker for vascular ageing. The development of an instrumentation solution for the combined assessment of pressure and flow of central arteries would accelerate the applicability of Windkessel model parameters in field settings.