Abstract Book from Artery 2025

Background:The arterial wall is an anisotropic, hyperelastic fibrous tissue subjected to biaxial loading.While constitutive models accurately capture its mechanical behaviour by accounting for individual wall constituents, simplified non-constitutive formulations are often preferred in one-dimensional haemodynamic simulations for computational efficiency.We aim to 1) evaluate non-constitutive arterial wall models' capability to capture human aortic mechanical behaviours and 2) quantify parameter changes across aortic regions.Methods: We used the four-fibre family model to generate pressurediameter curves of the descending thoracic, supraceliac, infrarenal, and distal abdominal aorta of N = 10 donors (age 62 11 years, 30% females) [1] by simulating pressurisation at fixed in vivo-like axial stretch [2].We then fitted the parameters of linear [3] and Langewouters pressure-diameter models [4] to these synthetic data.Results: The Langewouters model more accurately captured the simulated aortic pressure-diameter relationships than the linear model (R2 = 0.999 0.001 vs. 0.863 0.101, Figure A).The linear model's stiffness parameter E did not vary significantly with location.Conversely, two out of three Langewouters parameters (P0: maximum compliance pressure, Am: area-like parameter) dropped significantly along the aorta while P1 (half-width pressure) did not vary significantly (Figure B-E). Conclusion:The Langewouters model offers a better fit to the constitutive-based pressure-diameter curves, and its parameters show enhanced location sensitivity compared to the linear model, which is likely due to its ability of accurately recapitulating the complex nonlinear behaviour of the human aorta.