An integrated fluid-chemical model towards modeling the formation of intra-luminal thrombus in abdominal aortic aneurysms

• Main Authors: Jacopo eBiasetti, Pier Giorgio eSpazzini, Jesper eSwedenborg, Thomas Christian Gasser
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2012-07-01
• Series: Frontiers in Physiology
• Subjects: Thrombin; platelets; computational fluid dynamics; Abdominal Aortic Aneurysm; Coagulation Cascade; Convection-Diffusion-Reaction Equations
• Online Access: http://journal.frontiersin.org/Journal/10.3389/fphys.2012.00266/full

Abdominal Aortic Aneurysms (AAAs) are frequently characterized by the presenceof an Intra-Luminal Thrombus (ILT) known to influence biochemically and biomechanicallytheir evolution. ILT progression mechanism is still unclear and little is known regardingthe impact on this mechanism of the chemical species transported by blood flow.Chemical agonists and antagonists of platelets activation, aggregation, and adhesion andthe proteins involved in the coagulation cascade (CC) may play an important role in ILTdevelopment. Starting from this assumption, the evolution of chemical species involvedin the CC, their relation to coherent vortical structures (VSs) and their possible effect onILT evolution have been studied. To this end a fluido-chemical model that simulates theCC through a series of convection-diffusion-reaction (CDR) equations has been developed.The model involves plasma-phase and surface bound enzymes and zymogens, and includesboth plasma-phase and membrane-phase reactions. Blood is modeled as a non-Newtonianincompressible fluid. VSs convect thrombin in the domain and lead to the high concentration observed in the distal portion of the AAA. This finding is in line with the clinicalobservations showing that the thickest ILT is usually seen in the distal AAA region. Theproposed model, due to its ability to couple the fluid and chemical domains, provides anintegrated mechanochemical picture that potentially could help unveil mechanisms of ILTformation and development.