title: Effects of age-associated regional changes in aortic stiffness on human hemodynamics revealed by computational modeling.
abstract: Although considered by many as the gold standard clinical measure of arterial stiffness, carotid-to-femoral pulse wave velocity (cf-PWV) averages material and geometric properties over a large portion of the central arterial tree. Given that such properties may evolve differentially as a function of region in cases of hypertension and aging, among other conditions, there is a need to evaluate the potential utility of cf-PWV as an early diagnostic of progressive vascular stiffening. In this paper, we introduce a data-driven fluid-solid-interaction computational model of the human aorta to simulate effects of aging-related changes in regional wall properties (e.g., biaxial material stiffness and wall thickness) and conduit geometry (e.g., vessel caliber, length, and tortuosity) on several metrics of arterial stiffness, including distensibility, augmented pulse pressure, and cyclic changes in stored elastic energy. Using the best available biomechanical data, our results for PWV compare well to findings reported for large population studies while rendering a higher resolution description of evolving local and global metrics of aortic stiffening. Our results reveal similar spatio-temporal trends between stiffness and its surrogate metrics, except PWV, thus indicating a complex dependency of the latter on geometry. Lastly, our analysis highlights the importance of the tethering exerted by external tissues, which was iteratively estimated until hemodynamic simulations recovered typical values of tissue properties, pulse pressure, and PWV for each age group.
authors.affiliation: Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America.
authors.forename: Federica
authors.initials: F
authors.lastname: Cuomo
authors.affiliation: Department of Mechanical Engineering, Michigan State University, East Lansing, Michigan, United States of America.
authors.forename: Sara
authors.initials: S
authors.lastname: Roccabianca
authors.affiliation: Department of Biomedical Engineering, King's College London, London, United Kingdom.
authors.forename: Desmond
authors.initials: D
authors.lastname: Dillon-Murphy
authors.affiliation: Department of Biomedical Engineering, King's College London, London, United Kingdom.
authors.forename: Nan
authors.initials: N
authors.lastname: Xiao
authors.affiliation: Department of Biomedical Engineering, Yale University, New Haven, Connecticut, United States of America.|Vascular Biology and Therapeutics Program, Yale School of Medicine, New Haven, Connecticut, United States of America.
authors.forename: Jay D
authors.initials: JD
authors.lastname: Humphrey
authors.affiliation: Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America.|Department of Biomedical Engineering, King's College London, London, United Kingdom.|Department of Surgery, University of Michigan, Ann Arbor, Michigan, United States of America.
authors.forename: C Alberto
authors.identifier: http://orcid.org/0000-0002-3934-6506
authors.initials: CA
authors.lastname: Figueroa
mesh_terms: D000328:Adult; D000368:Aged; D001011:Aorta / Q000503:physiopathology*; D019295:Computational Biology; D006439:Hemodynamics; D006801:Humans; D008875:Middle Aged; D008954:Models, Biological; D063177:Pulse Wave Analysis; D059289:Vascular Stiffness