Effect of Intermitent Hypoxia on the Viscoelastic Response of the Thoracic Aorta

Abstract

A variety of studies have demonstrated that the adaptability capacity of arteries is manifested when they are exposed to intermittent hypoxia conditions for prolonged periods, where as the frequency of intermittent hypoxia cycles increases, arterial tissue tends to adopt a behavior similar to that observed in cases of normoxia. Thus, the present work seeks to study this adaptability phenomenon by validating a visco-hyperelastic constitutive model using mechanical tests of equibiaxial traction and relaxation performed in the thoracic aortic arteries of three different groups of rats (control, four and ten cycles of hypoxia, respectively). Product of the anisotropic tissue response is that the Gasser-Ogden-Holzapfel model is used for the hyperelastic response (T.C. Gasser et al., J Royal Soc Int, 3:15-35 (2006)) and to reproduce the viscous nonlinear response the Latorre model is used (M. Latorre and F. Montáns, Comp & Str, 163:56-70 (2015)) which uses a multiplicative decomposition of the deformation gradient. Both models are implemented in the FEBio code, which uses the finite element method to obtain simulations for each characterized arterial group.