Abdominal Aortic Aneurysm Modelling
Stanford University, ME285 - Cardiovascular Modeling, Spring 2019
CFD modeling can be used to better understand AAA development and treatment options. SimVascular was used to perform a 1D and 3D simulation to understand fluid flow through the vessels, changes in pressure, wall shear stress, and wall displacement. While some values from the simulations matched the literature, there were some differences, particularly with pressure values. To improve this, deformable models could be optimized and different boundary conditions could be added (RCR circuits). The model could also be coupled with a larger lumped parameter network to simulate a closed loop system along with more major organs and vessels such as the heart. In terms of modeling, the mesh can be optimized to minimize computation time while minimizing the accuracy losses. Clinically, modeling and simulating flow through patient vasculature can aid in treating and tracking AAA. Because over 45,000 AAA surgeries are performed each year (McPhee et al., 2007) with a 10% mortality rate (Dawson et al., 2010), it is important to understand when intervention is needed. AAA modeling has shown that aneurysm diameter, the main method by which surgery is decided, is an inferior method of rupture estimation compared to wall shear stress (Boyd et al., 2016; Boussel et al., 2008). Additionally, modelling can be used to predict aneurysm growth (Stevens et al., 2016) to help inform patients of their outcome (Golledge & Norman, 2009). AAA CFD modeling enables better prediction and rupture estimation for patients and can be used more widely when evaluating surgical procedures and patient monitoring.