Characterization of the Active Response of Carotid Arteries

Abstract

This work presents an experimental and computational methodology to characterize the active and passive biomechanical response of the carotid artery under intermittent hypobaric hypoxia (IHH), using ex vivo pressure myography in rats exposed to normoxia and to 4 and 10 cycles of IHH. Active and passive responses are evaluated in KCl-rich and calcium-free solutions, respectively, recording real-time diameter and axial force to estimate myogenic tone, stiffness, and distensibility. These data are used to fit an active constitutive model based on Murtada’s chemo-mechanical formulation, which decomposes the strain energy into passive and active components. The model is implemented via the finite element method (FEM), enabling realistic simulations of pressurized arteries and assessment of how hypoxia alters the vessel’s mechanical regulation. Given the impact of intermittent hypoxia on vascular health in populations exposed to high altitude, understanding how this condition alters arterial mechanics at both functional and structural levels is essential.