  Thoracic endovascular aortic repair (TEVAR) has become the standard treatment
of a variety of aortic pathologies. The objective of this study is to evaluate
the hemodynamic effects of stent-graft introducer sheath during TEVAR. Three
idealized representative diseased aortas of aortic aneurysm, coarctation of the
aorta, and aortic dissection were designed. Computational fluid dynamics
studies were performed in the above idealized aortic geometries. An introducer
sheath routinely used in the clinic was virtually-delivered into diseased
aortas. Comparative analysis was carried out to evaluate the hemodynamic
effects of the introducer sheath. Results show that the blood flow to the
supra-aortic branches would increase above 9% due to the obstruction of the
introducer sheath. The region exposed to high endothelial cell activation
potential (ECAP) expands in the scenarios of coarctation of the aorta and
aortic dissection, which indicates that the probability of thrombus formation
may increase during TEVAR. The pressure magnitude in peak systole shows an
obvious rise and a similar phenomenon is not observed in early diastole. The
blood viscosity in the aortic arch and descending aorta is remarkably altered
by the introducer sheath. The uneven viscosity distribution confirms the
necessity of using non-Newtonian models and high viscosity region with high
ECAP further promotes thrombosis. Our results highlight the hemodynamic effects
of stent-graft introducer sheath during TEVAR, which may associate with
perioperative complications.
