Investigation of hemodynamic effect of stent wires on renal arteries in patients with abdominal aortic aneurysms treated with suprarenal stent grafts

Abstract

The purpose of the study was to investigate the hemodynamic effect of stent struts (wires) on renal arteries in patients with abdominal aortic aneurysms (AAA) treated with suprarenal stent grafts. Two sample patients with AAA undergoing multislice CT angiography pre-and post-suprarenal fixation of stent grafts were selected for inclusion in the study. 3D aorta models (4 in total) containing the main aortic artery branches were generated from the multislice CT datasets. Four types of configurations of stent wires crossing the renal artery ostium, namely single wire central crossing, single wire peripherally crossing, V-shaped wire centrally crossing and multiple wires peripherally crossing were simulated in the segmented aorta models. The blood flow pattern and flow velocity to the renal arteries pre-and post-stent grafting were analyzed and compared using a two-way fluid structure interaction analysis. The stent wire thickness was simulated with a diameter of 0.4 mm, 1.0 mm and 2.0 mm, and hemodynamic analysis was performed at different cardiac cycles. Our results showed that the interference of stent wires with renal blood flow was determined by the number and configuration of stent wires crossing the renal artery ostium. The flow velocity was found to decrease significantly with multiple stent wires, especially the V-shaped type crossing the renal artery ostium, and with the wire thickness being 1.0 mm and 2.0 mm. No significant difference of flow velocity was noticed with a single wire crossing, regardless of variable simulated wire thicknesses, or the type of configuration. In conclusion, our preliminary study showed that the hemodynamic effect of suprarenal stent wires in patients with AAA treated with suprarenal stent grafts is dependent on the number and type of configuration of stent wire crossing the renal artery ostium. Research findings in our study are considered useful for follow-up of patients treated with suprarenal stent grafts to ensure long-term safety of the suprarenal fixation.