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Title: Investigation of the 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 (AAAs) treated with suprarenal stent-grafts. Two sample patients with AAA undergoing multislice CT angiography pre- and postsuprarenal 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 were simulated in the segmented aorta models: a single wire crossing centrally, a single wire crossing peripherally, a V-shaped wire crossing centrally, and multiple wires crossing peripherally. 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, 1.0, and 2.0 mm, and hemodynamic analysis was performed at different cardiac cycles. 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 themore » situations when the stent wire thickness increased to 1.0 and 2.0 mm. Of the four 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. In 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.« less

Authors:
 [1];  [2]
  1. Curtin University of Technology, Discipline of Medical Imaging, Department of Imaging and Applied Physics (Australia)
  2. King Mongkut's Institute of Technology Ladkrabang, Department of Electronic Engineering (Thailand)
Publication Date:
OSTI Identifier:
21428506
Resource Type:
Journal Article
Resource Relation:
Journal Name: Cardiovascular and Interventional Radiology; Journal Volume: 32; Journal Issue: 4; Other Information: DOI: 10.1007/s00270-009-9539-1; Copyright (c) 2009 Springer Science+Business Media, LLC and the Cardiovascular and Interventional Radiological Society of Europe (CIRSE); Article Copyright (c) 2009 Springer Science+Business Media, LLC
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; ABDOMEN; AORTA; BIOMEDICAL RADIOGRAPHY; BLOOD FLOW; CONFIGURATION; FLUID-STRUCTURE INTERACTIONS; GRAFTS; KIDNEYS; SHEAR; SIMULATION; STRESSES; TUBES; VELOCITY; WALLS; WIRES; ARTERIES; BLOOD VESSELS; BODY; CARDIOVASCULAR SYSTEM; DIAGNOSTIC TECHNIQUES; MEDICINE; NUCLEAR MEDICINE; ORGANS; RADIOLOGY; TRANSPLANTS

Citation Formats

Sun Zhonghua, E-mail: z.sun@curtin.edu.a, and Chaichana, Thanapong. Investigation of the Hemodynamic Effect of Stent Wires on Renal Arteries in Patients with Abdominal Aortic Aneurysms Treated with Suprarenal Stent-Grafts. United States: N. p., 2009. Web. doi:10.1007/S00270-009-9539-1.
Sun Zhonghua, E-mail: z.sun@curtin.edu.a, & Chaichana, Thanapong. Investigation of the Hemodynamic Effect of Stent Wires on Renal Arteries in Patients with Abdominal Aortic Aneurysms Treated with Suprarenal Stent-Grafts. United States. doi:10.1007/S00270-009-9539-1.
Sun Zhonghua, E-mail: z.sun@curtin.edu.a, and Chaichana, Thanapong. 2009. "Investigation of the Hemodynamic Effect of Stent Wires on Renal Arteries in Patients with Abdominal Aortic Aneurysms Treated with Suprarenal Stent-Grafts". United States. doi:10.1007/S00270-009-9539-1.
@article{osti_21428506,
title = {Investigation of the Hemodynamic Effect of Stent Wires on Renal Arteries in Patients with Abdominal Aortic Aneurysms Treated with Suprarenal Stent-Grafts},
author = {Sun Zhonghua, E-mail: z.sun@curtin.edu.a and Chaichana, Thanapong},
abstractNote = {The purpose of the study was to investigate the hemodynamic effect of stent struts (wires) on renal arteries in patients with abdominal aortic aneurysms (AAAs) treated with suprarenal stent-grafts. Two sample patients with AAA undergoing multislice CT angiography pre- and postsuprarenal 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 were simulated in the segmented aorta models: a single wire crossing centrally, a single wire crossing peripherally, a V-shaped wire crossing centrally, and multiple wires crossing peripherally. 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, 1.0, and 2.0 mm, and hemodynamic analysis was performed at different cardiac cycles. 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 and 2.0 mm. Of the four 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. In 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.},
doi = {10.1007/S00270-009-9539-1},
journal = {Cardiovascular and Interventional Radiology},
number = 4,
volume = 32,
place = {United States},
year = 2009,
month = 7
}
  • The endovascular repair of abdominal aorticaneurysm (AAA) with stent grafts is rapidly becoming an important alternative to open repair. Suprarenal stent grafting, recently modified from conventional infrarenal stent grafting, is a technique for the purpose of treating patients with inappropriate aneurysm necks.Unlike open repair, the success of endoluminal repair cannot be ascertained by means of direct examination and thus relies on imaging results. The use of conventional angiography for arterial imaging has become less dominant, while helical computed tomography angiography(CTA) has become the imaging modality of choice for both preoperative assessment and postoperative followup after treatment with stent graft implants.more » There is an increasing likelihood that radiologists will become more and more involved in the procedure of aortic stent grafting and in giving the radiological report on these patients treated with stent grafts. It is necessary for radiologists to be familiar with the imaging findings, including common and uncommon appearances following aortic stent grafting. The purpose of this pictorial essay is to describe and present normal and abnormal imaging appearances following aortic stent grafting based on helical CTA.« less
  • Aortic stent-grafts were introduced at the beginning of the 1990s as a less invasive method of dealing with aortic aneurysms in patients with poor cardiovascular reserve. The numbers of procedures performed worldwide has increased exponentially despite the current lack of any substantial evidence for long-term efficacy in comparison with the gold standard of open surgical grafting. This review summarizes the evolution of the abdominal aortic stent-graft, the techniques used for assessment and deployment, and the effect of the procedure on both the patient and the device. The recent publication of two national multicenter trials has confirmed that the endovascular techniquemore » confers a 2.5-fold reduction in 30-day mortality in comparison with open surgery. However, over 4 years of follow-up, there is a 3-fold increase in the risk of reintervention and the overall costs are 30% greater with endovascular repair. Although the improvement in aneurysm-related mortality persists in the mid-term, because of the initial reduction in perioperative mortality, the all-cause mortality rate at 4 years is actually no better than for open surgery. Longer-term data from the randomized trials are awaited as well as results from the latest trials utilizing state-of-the-art devices. Whilst the overall management of abdominal aortic aneurysms has undoubtedly benefited from the introduction of stent-grafts, open repair currently remains the gold standard treatment.« less
  • To quantitatively characterize processes of platelet thrombus formation in vivo, the kinetics and incorporation into thrombus of autologous In-111-labeled platelets were compared in six patients with aortic aneurysms and in seven patients with prosthetic aortic grafts. Although platelet survival was comparably shortened in both patient groups (mean, 5.8 days), the maximum radioactivity as determined by gamma camera imaging was higher in the aneurysms than in the grafts (3.3% +/- 1.6% vs. 1.6% +/- 1.1%, p = 0.05). Maximum In-111 uptake was also attained more quickly in the aneurysm patients (2.3 +/- 0.8 days vs. 3.5 +/- 1.3 days; p =more » 0.07). The experimental platelet kinetic and imaging data were subsequently evaluated by compartmental analysis to estimate both normal and disease-related components of platelet destruction. This analysis indicated that deposited platelet radioactivity had a longer residence time on grafts (2.9 +/- 1.7 days vs. 1.4 +/- 0.9 days, p = 0.07) but accumulated at a faster rate in aneurysms (5.0% +/- 3.4% per day vs. 1.4% +/- 0.9% per day, p = 0.02). As determined by imaging, only a proportion of increased platelet destruction was specifically due to the aneurysms (55% +/- 38%) or grafts (17% +/- 11%, p = 0.03). This result indicates additional components of platelet destruction unrelated to graft and aneurysm thrombus formation which, in some graft patients, may reflect a greater severity of vascular disease or other mechanisms causing a preferential shortening of platelet survival. Thus, the analytical approach described may be a useful one for discriminating components of in vivo platelet utilization including platelet removal due to normal hemostatic and senescent mechanisms, localized thrombus formation, and more generalized vascular disease.« less
  • A three-dimensional model was constructed from helical CT images for abdominal aortic aneurysm (AAA) and thoracic aortic aneurysm (TAA). A stent-graft was designed and positioned endoluminally on the computer. One hundred and nine stent-grafts for 101 patients were designed by this method and deployed well in all patients. The design time was reduced from 4 to 0.5 hr.
  • No abstract prepared.