From detection to rupture: A serial computational fluid dynamics case study of a rapidly expanding, patient-specific, ruptured abdominal aortic aneurysm

Computational hemodynamic studies of abdominal aortic aneurysm (AAA) can help elucidate the mechanisms responsible for growth and development. The aim of this work is to determine if AAAs expand and develop intraluminal thrombus (ILT) in regions of low wall shear stress (WSS) predicted with computational fluid dynamics (CFD). Computed tomography (CT) data of an AAA was acquired at four time-points over 2.5 years, from the time of detection to immediately prior to rupture. We used 3D unsteady, laminar, CFD models to investigate the hemodynamics at each time-point. Our three-dimensional reconstructions showed that the primary region of expansion was in the proximal lobe, which not only coincided with the main region of low time-averaged WSS (TAWSS) in our CFD simulations, but also with the development of ILT in vivo. Interestingly, this region was also the rupture location. This is the first serial computational study of an AAA and the work has shown the potential of CFD to model the changing hemodynamics and the relation with ILT development and AAA growth.