Fluid structure interaction for patient specific risk assessment in ruptured abdominal aortic aneurysms

Rupture of abdominal aortic aneurysm (AAA), having a mortality rate of 50-75%, ranks as the 13th leading cause of death in the US. The ability to reliably predict the risk of rupture of AAA on a patient-specific basis could vastly improve the clinical management of these patients. Computed tomography scans of patients that arrived at Stony Brook University Hospital emergency room, with contained ruptures of the abdominal aorta, were obtained prior to surgery. Three-dimensional AAA geometries were reconstructed to model the AAA at the threshold of rupture. Fluid structure interaction (FSI) modeling was performed to predict the location of rupture by mapping the stress distribution within the aneurismal wall. Advanced constitutive material models were utilized to incorporate an anisotropic wall fiber orientation into the vessel wall. FSI simulations incorporated these material properties and extract stress distribution maps and other hemodynamic parameters, such as blood velocity, to pinpoint regions of high rupture risk. Results from FSI simulations indicate a positive correlation between the simulated region of highest wall stress and original region of rupture. The highest wall stress occurs during peak systole and is higher than 0.5 MPa. Ultimately, this information can provide a quantitative clinical assessment of rupture risk for AAAs.