Computational hemodynamics in the human aorta: A computational fluid dynamics study of three cases with patient-specific geometries and inflow rates

Abstract

To demonstrate the potential role of computational fluid dynamics (CFD) in therapeutic decision making for treatment of vascular pathologies of the human aorta. CFD simulations with patient specific geometries and patient-specific inflow boundary conditions obtained with magnetic resonance imaging were performed in three cases: 1) mobile thrombus in the aortic arch in a patient with ischemic stroke 2) acute type II B aortic dissection 3) abdominal aortic aneurysm repaired with an endoluminal graft. Blood flow pathlines, wall shear stresses (WSS), dynamic pressures, blood velocities and flow particle resident times were calculated. Aortic thrombus was indicated as possible source of emboli by flowlines and elevated WSS (8% higher than average WSS at aortic wall) in case 1. This was not identified on conventional imaging. In case 2, the false lumen of the dissection showed elevated pressures and high blood velocities at systole but low pressures and stagnant flow at other times (blood velocity < 0.02 m/s and WSS < 0.1 Pa). Flow disturbances at the reentrance zone of blood from the false lumen were recognized. For case 3, elevated WSS at the landing zone of the endoluminal graft and at the right iliac section together with disturbed flow patterns and increased flow particle resident times were noted. Focal stenoses coincided with the flow disturbances. Measured velocity patterns were qualitatively in agreement with velocity patterns calculated with CFD. CFD simulations provide additional information of the hemodynamics in the diseased human aorta and may have potential in aiding the therapeutic decision making process.