Comparison of hemodynamics in post-operation coarctation of aorta patients with different aortic arch geometry

Aim: Coarctation of the aorta (CoA) is associated with post-operation deformation and abnormal hemodynamics. The objective of this work is to quantify hemodynamic alterations with different vascular structures of post-operation CoA with computational fluid dynamics techniques. Methods: A total of 4 patients with different aortic shapes were included in the research: No.1=no stenosis; No.2=slight stenosis (stenosis/descending=78.3%); No.3=moderate to severe stenosis (stenosis/descending= 55.7%) and No.4= angular aortic arch. MR axial images were adopted and phase-contrast sequence provided the inlet velocity-time curve. A three-dimensional model for simulation was modeled by Mimics 17.0 and Fluent 15.0 was applied to simulate the blood flow within the thoracic aorta. Measurements of relevant hemodynamic parameters included streamline, wall pressure and wall shear stress (WSS). Results: The hemodynamic parameters of thoracic aorta at three-time phases were demonstrated. Compared to the patient with normal arch, the stenosis site had higher velocity, wall pressure and WSS, but reduced after stenosis. Patients with minor stenosis had less vortex and turbulence, usually at the site of dilation after stenosis. The impinging velocity jet could be less severe as well. For patient with angulated arch, the vortices and turbulence could be more severe and began from the arch to the distal region of the descending aorta. WSS usually got lower in the place where vortex occurred, but in the vortices with higher velocity, the pressure and WSS would turn higher. Conclusion: With more severe deformation of the big arteries, the hemodynamic change of blood flow was more obvious.