A mechanistic model on the role of "radially-running" collagen fibers on dissection properties of human ascending thoracic aorta.
Aortic dissection (AoD) is a common condition that often leads to life-threatening cardiovascular emergency. From a biomechanics viewpoint, AoD involves failure of load-bearing microstructural components of the aortic wall, mainly elastin and collagen fibers. Delamination strength of the aortic wall depends on the load-bearing capacity and local micro-architecture of these fibers, which may vary with age, disease and aortic location. Therefore, quantifying the role of fiber micro-architecture on the delamination strength of the aortic wall may lead to improved understanding of AoD. We present an experimentally-driven modeling paradigm towards this goal. Specifically, we utilize collagen fiber micro-architecture, obtained in a parallel study from multi-photon microscopy, in a predictive mechanistic framework to characterize the delamination strength. We then validate our model against peel test experiments on human aortic strips and utilize the model to predict the delamination strength of separate aortic strips and compare with experimental findings. We observe that the number density and failure energy of the radially-running collagen fibers control the peel strength. Furthermore, our model suggests that the lower delamination strength previously found for the circumferential direction in human aorta is related to a lower number density of radially-running collagen fibers in that direction. Our model sets the stage for an expanded future study that could predict AoD propagation in patient-specific aortic geometries and better understand factors that may influence propensity for occurrence.
Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States.
Siladitya
S
Pal
Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States; Center for Vascular Remodeling and Regeneration, University of Pittsburgh, Pittsburgh, PA, United States; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States.
Alkiviadis
A
Tsamis
Fondazione Ri.MED, University of Palermo, Palermo, Italy; DICGM University of Palermo, Palermo, Italy.
Salvatore
S
Pasta
McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States; Fondazione Ri.MED, University of Palermo, Palermo, Italy; DICGM University of Palermo, Palermo, Italy.
Antonio
A
D'Amore
Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States; Department of Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, PA, United States; Center for Vascular Remodeling and Regeneration, University of Pittsburgh, Pittsburgh, PA, United States; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States.
Thomas G
TG
Gleason
Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States; Department of Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, PA, United States; Department of Surgery, University of Pittsburgh, Pittsburgh, PA, United States; Center for Vascular Remodeling and Regeneration, University of Pittsburgh, Pittsburgh, PA, United States; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States.
David A
DA
Vorp
Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States. Electronic address: spm54@pitt.edu.
Spandan
S
Maiti
D000784:Aortic Dissection / Q000209:etiology*; D000818:Animals; D001013:Aorta, Thoracic / Q000502:physiology*; D017545:Aortic Aneurysm, Thoracic / Q000209:etiology*; D001696:Biomechanical Phenomena; D004549:Elastin / Q000502:physiology; D005109:Extracellular Matrix / Q000502:physiology; D005260:Female; D024022:Fibrillar Collagens / Q000502:physiology*; D006801:Humans; D008955:Models, Cardiovascular; D016474:Weight-Bearing
D024022:Fibrillar Collagens; D004549:Elastin
Aorta; Collagen fibers; Dissection; Fiber bridge failure model; Peel force