Influence of Left Subclavian Artery Stent Graft Geometry on Blood Hemodynamics in Thoracic Endovascular Aortic Repair.

Objective: To analyze the hemodynamic changes in different configurations of left subclavian artery (LSA) stent grafts after LSA endovascular reconstruction in thoracic endovascular aortic repair (TEVAR).

Methods: For numerical simulation, one 3D thoracic aortic geometry model with an LSA stent graft retrograde curved orientation was reconstructed from post-TEVAR computed tomography angiography images, and four potential LSA graft configurations were modified and reconstructed: three straight (0, 2 and 10 mm aortic extension) and one anterograde configuration. The blood perfusion of the LSA, flow field, hemodynamic wall parameters and vortex evolution process visualized by the Liutex method were analyzed.

Results: The average flow in the retrograde configuration decreased by 11.2% compared to that in the basic configuration. When the LSA stent graft extends in the aortic lumen, Flow separation is observed, and vortex structures begin to form at the proximal inferior arterial geometry and the wall of the extension in late systole. A greater extension length and inflow angle upstream resulted in a greater OSI and RRT on the nearby wall of the posterior flow field of the extension.

Conclusions: Shorter intra-aortic extension length and smaller LSA stent graft inflow angle may be recommended in TEVAR, considering LSA perfusion and thrombosis risk.