Progression of Abdominal Aortic Aneurysm: Effect of Lagrangian Transport and Hemodynamic Parameters

Abdominal aortic aneurysm (AAA) is a permanent, localized enlargement of the abdominal aorta that accompanies disturbed blood flow, which is thought to perpetuate aneurysm progression. AAA rupture is a leading cause of death in the elderly and an exact intervention decision for this disease has always been associated with uncertainty. There is currently no medicinal treatment of AAA, however lower extremity exercise has been a proposed therapy. Specifically, elevated flow rates in the abdominal aorta, reduced retrograde flow, higher mean wall shear stress, and lower oscillatory shear index resulting from exercise have been hypothesized as beneficial in preventing or slowing AAA. Computational fluid dynamics (CFD) has recently been used to model flow conditions inside AAA with an aim to better understand the biomechanical underpinnings of this disease. Recent studies have used patient-specific computational models, however few studies have looked in detail to AAA transport topology or correlated their results with aneurysm progression data. This study aims to (1) compare the flow topology between rest and exercise conditions in patients with small AAA to understand specifically how blood transport changes from rest to exercise, and (2) compare flow parameters obtained by CFD to the aneurysm progression.