Biomechanical Simulation of Evolving Aortic Aneurysms for Designing Intervention

Unknown Finite elment analysis of two different geometrical AAA models. Maximum principal stress fields in an asymmetric (a) and a symmetric (b) aneurysm.

Abdominal aortic aneurysms (AAAs) are most common in men aged 65 and older, and the incidence of this disease is therefore on the rise in our aging population. It is universally agreed that mechanical factors play key roles in the natural history of AAAs and their response to treatment, yet there is no widely accepted tool for quantifying or predict the mechanobiology and biomechanics of AAAs.

Our overall goal is to support and extend the Cardio- vascular Fluid Dynamics Project at the Symbios National Center for Biomedical Computing at Stanford University by

  1. developing novel constitutive relations that describe complex chemo-mechanical changes experienced by the abdominal aorta during the progression of aneurysmal disease

  2. implementing these relations in a custom nonlinear FE code

  3. interfacing this arterial mechanics code with the Stanford biofluid mechanics code to enable us to quantify, for the first time, the fluid-solid-growth mechanics of a growing AAA

  4. using parametric studies and data to refine and verify the predictive capability of this computational tool.

We bring together expertise from different institutions: JD Humphrey (Yale University) has expertise in developing complex constitutive theories for soft tissues, D Vorp (University of Pittsburgh) has expertise in quantifying biomechanical properties of abdominal aortic aneurysms and associated intraluminal thrombi, GA Holzapfel (TU Graz) has expertise in computational biosolid mechanics, C Taylor (Stanford University) with expertise in computational biofluid mechanics, and C Zarins (Stanford University) with expertise in vascular surgery and animal models of disease progression. Together, we will develop the first computational tool to better understand the natural history of aneurysms and responses to intervention of AAA. The tool extends the cardiovascular research capabilities at the Stanford University National Center for Biomedical Computing.

Funding: National Institutes of Health (NIH)