Intraluminal thrombus exacerbates wall hypoxia in abdominal aortic aneurysms

The probability of aneurysm rupture is correlated with weakening of the vessel wall, which may be caused by hypoxia.  Many aneurysms contain intraluminal thrombus, and this is hypothesized to promote wall hypoxia by creating a barrier between the oxygen-rich lumen and the wall. Our work describes a method developed to test this hypothesis and an application of this method to a patient-specific aneurysm. Our three-layer model includes the lumen, thrombus, and wall. Coupled Navier-Stokes and scalar transport equations were solved in the lumen layer. Oxygen diffusion and consumption employing Michaelis-Menten kinetics were modeled in the wall layer. The thrombus was modeled with nonzero oxygen diffusion, but no flow or oxygen consumption. The inlet and outlet flow rates were chosen to match physiological Reynolds numbers. Our computations in the sample model illustrate reduced oxygen supply in the presence of thrombus.  Oxygen diffusion flux across the thrombus/wall interface is negatively correlated with thrombus thickness. The oxygen concentration at the thrombus/wall interface does not vary significantly with thrombus thickness beyond a thrombus thickness of 5 mm. Oxygen concentration profiles within the wall will also be presented.