The effect of the length of chimney's protrusion on the hemodynamics of abdominal aorta stent graft after endovascular aneurysm repair

Introduction: Abdominal aortic aneurysms present a significant clinical challenge, particularly when located near the renal arteries. In cases of infra-renal abdominal aortic aneurysms, the main stent graft may occlude the renal arteries, disrupting blood supply. To prevent this, two 'chimney' stent grafts can be implanted to maintain renal artery perfusion. Method: This study investigates the impact of chimney stent graft protrusion length on the hemodynamics of stent graft using computational fluid dynamics (CFD). Two chimney configurations were analyzed, with the chimney protruding 10 and 30 mm above the upper part of the main stent graft. Key hemodynamic parameters were compared, including wall shear stress, blood flow velocity, and pathlines. Results: The CFD analysis showed no substantial differences in hemodynamic parameters between these configurations. Conclusions: The findings indicate negligible hemodynamic differences between the two chimney configurations. A chimney that protrudes 30 mm above the main stent graft is a viable option and may help reduce procedure time and patient risk.