Investigation of the Hemodynamic Effect of Stent Wires on Renal Arteries in Patients with Abdominal Aortic Aneurysms Treated with Suprarenal Stent-Grafts

Abstract

Investigation of hemodynamic effect of stent wires on renal arteries in patients with abdominal aortic aneurysms treated with suprarenal stent grafts 2 Abstract Purpose: 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. Materials and Methods:Two sample patients with AAA undergoing multislice CT angiography pre-and post-suprarenal fixation of stent grafts were selected for inclusion in the study. Eight juxtarenal models focusing on the renal arteries were generated from the multislice CT datasets. Four types of configurations of stent wires crossing the renal artery ostium, namely single wire centrally crossing, single wire peripherally crossing, Vshaped wire centrally crossing and multiple wires peripherally crossing were simulated in the segmented aorta models. The blood flow pattern, flow velocity, wall pressure and wall shear stress at 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. Results:The interference of stent wires with renal blood flow was mainly determined by the thickness of stent wires, and the type of configuration of stent wires crossing the renal ostium. The flow velocity was reduced by 20-30% in most of the situations when the stent wire thickness increased to 1.0 mm and 2.0 mm. Of 4 types of configuration, the single wire crossing centrally resulted in the highest reduction of flow velocity, ranging from 21% to 28.9% among three different wire thicknesses. Wall shear stress was also dependent on the wire thickness, which decreased significantly when the wire thickness reached 1.0 and 2.0 mm.3 Conclusion: Our preliminary study showed that the hemodynamic effect of suprarenal stent wires in patients with AAA treated with suprarenal stent grafts was determined by the thickness of suprarenal stent wires. Research findings in our study are useful for follow-up of patients treated with suprarenal stent grafts to ensure long-term safety of the suprarenal fixation.

Suprarenal versus infrarenal stent graft fixation on renal complications after endovascular aneurysm repair

“…35 Some have reported that the thickness of SR stent wires crossing the renal artery ostia influences renal artery flow velocity. 36 However, others have shown no deleterious effect of SR fixation in renal artery morphology and function. 37 The conflicting literature on this topic may be partially explained by the inherent anatomic variability in the interaction between SR stent struts and renal artery ostia, with SR stent struts crossing the renal artery ostia in 50% to 80% of patients.…”

Computational Fluid Dynamics Analysis of the Effect of Plaques in the Left Coronary Artery

“…The tetrahedral mesh configuration was 15,519 nodes and 78,618 elements. The meshes were generated using ANSYS ICEM CFD version 12 (ANSYS, Inc., Canonsburg, PA, USA), with details having been described in previous studies [6, 14, 15]. Finally, both mesh models were saved in “GTM format” for CFD computation.…”

Endovascular stent graft repair of abdominal aortic aneurysms: Current status and future directions

“…Researchers studied the fluid-stent graft interaction based on AAA models with a focus on infrarenal fixation of stent grafts [39][40][41] . Our previous experiments based on realistic aorta models with variable configurations of suprarenal stent wires crossing the renal artery ostium showed that multiple wire configuration leads to a significant decrease in flow velocity to the renal artery, while single wire crossing has a minimal effect on the renal flow changes (Figure 14) [42] . For fenestrated stent grafting, the hemodynamic analysis showed that the interference of fenestrated renal stents with the renal blood flow is 67 WJR|www.wjgnet.com Sun Z. Endovascular stent graft repair of aortic aneurysms minimal and insignificant, so this indicates the safety of deploying the fenestrated renal stents inside the renal arteries ( Figure 15) [43] .…”