Wall Stresses Before and After Endovascular Repair of Abdominal Aortic Aneurysms

2004 ◽  
Author(s):  
Elena S. Di Martino ◽  
Ajay Bohra ◽  
Christine Scotti ◽  
Ender Finol ◽  
David A. Vorp
Keyword(s):  
Endovascular Aneurysm Repair ◽  
Three Dimensional ◽  
Invasive Procedure ◽  
Aortic Aneurysms ◽  
Aortic Tissue ◽  
Type I ◽  
Abdominal Aortic ◽  
Before And After ◽  
Anchoring System ◽  
Three Dimensional Finite Element

Endovascular aneurysm repair (EVAR) technique is a minimally invasive procedure approach to abdominal aortic aneurysm (AAA) repair. Following EVAR, isolated aortic tissue starts remodeling after the new blood path is established. The commercially available endovascular grafts (EVG) have been found to be prone to Type I endoleak, which is re-pressurization of the degenerated AAA sac following a breach in the seal mechanism of the EVG or migration due to failure of the mechanism holding the graft in place (Chuter, 2002) These inadequacies of EVGs might be attributed to the effect of non-optimal design of graft anchoring system. In the present study, we utilized pre-operative and post-operative computer tomography (CT) data with previously derived material properties to construct three-dimensional finite element (FE) models for AAA before and after the EVAR procedure. We studied the nature of stresses acting on the aorta before and after EVAR. In particular we investigated the physical forces acting on the EVG and how they are transferred to the aortic wall at graft anchoring sites.

Endovascular abdominal aortic aneurysm repair in patients with Marfan syndrome

Vascular ◽  
2019 ◽  
Vol 28 (1) ◽  
pp. 48-52
Author(s):  
Allan Marc Conway ◽  
Khalil Qato ◽  
Gautam Anand ◽  
Laurie Mondry ◽  
Gary Giangola ◽  
...  
Keyword(s):  
Marfan Syndrome ◽  
Open Repair ◽  
Aortic Surgery ◽  
Endovascular Aneurysm Repair ◽  
Aortic Aneurysms ◽  
Type I ◽  
Femoral Access ◽  
Abdominal Aortic ◽  
Aneurysm Repair

Objectives Marfan syndrome patients are at risk for aortic degeneration. Repair is traditionally performed with open surgery as this is deemed more durable. Endovascular aneurysm repair remains controversial. We report on the outcomes of Marfan syndrome patients with abdominal aortic aneurysms undergoing endovascular aneurysm repair. Methods The Vascular Quality Initiative registry identified 35,889 patients, including 29 with Marfan syndrome, treated with endovascular aneurysm repair from January 2003 to December 2017. Outcomes were analyzed per the Society for Vascular Surgery reporting standards. Results Median age was 70.0 years (IQR, 57.0–75.0), and 22 (75.9%) were male. Median aneurysm diameter was 5.3 cm (IQR, 4.9–6.3 cm), with an aortic neck length and diameter of 2.0 cm (IQR, 1.6–2.8 cm) and 2.5 cm (IQR, 2.2–2.8 cm), respectively. Twenty-one (72.4%) patients were asymptomatic, seven (24.1%) symptomatic, and one (3.4%) presented with rupture. Ten (34.5%) patients had prior aortic surgery. Six (20.7%) were unfit for open surgical repair. Length of stay was 2.0 days (IQR, 1.0–3.0 days). Percutaneous femoral access was performed in 15 (51.7%) patients with no complications. A type IA endoleak was present in one (3.4%), type IB in one (3.4%), and type II endoleak in two (6.9%) patients. There were no postoperative pulmonary, cardiac, or neurological complications. In-hospital mortality occurred in one (3.4%) patient who presented with a rupture and had been deemed unfit for open repair. A conversion to open repair was required. The patient expired on post-operative day 0. Early clinical success was achieved in 26 (89.7%) patients. Follow-up was available for 15 (51.7%) patients at a median time of 766 days (IQR, 653–937). There were no reinterventions or mortalities. Change in sac diameter was −0.6 cm (IQR, −1.1 to −0.2 cm), with no type I or III endoleaks. Discussion Endovascular aneurysm repair for patients with Marfan syndrome is feasible, and can be performed safely. Mid-term outcomes suggest this technique is durable. More robust long-term follow-up is needed.

Anisotropic Wall Mechanics of Abdominal Aortic Aneurysms

2008 ◽  
Author(s):  
Giampaolo Martufi ◽  
Jose F. Rodriguez ◽  
Ender A. Finol
Keyword(s):  
Three Dimensional ◽  
Wall Stress ◽  
Aortic Aneurysms ◽  
Constitutive Law ◽  
Intraluminal Pressure ◽  
Aortic Tissue ◽  
Unruptured Aneurysms ◽  
Abdominal Aortic ◽  
Dimensional Reconstruction ◽  
Tissue Specimens

The prevalence of AAA is growing along with population age and according to different studies AAA rupture is the 13th most common cause of death in the U.S., causing an estimated 15,000 deaths per year. In biomechanical terms, AAA rupture is a phenomenon that occurs when the developing mechanical stresses within the aneurysm inner wall, as a result of the exerted intraluminal pressure, exceed the failure strength of the aortic tissue. To obtain a reliable estimation of wall stress, it is necessary to perform an accurate three-dimensional reconstruction of the AAA geometry and model an appropriate constitutive law for the aneurysmal tissue material characterization. In this regard, a recent study on the biaxial mechanical behavior of human AAA tissue specimens [1] demonstrates that aneurysmal arterial tissue behaves mechanically anisotropic. The objectives of the present work are to determine the effect of material anisotropy of the aneurysmal abdominal aorta on wall stress distribution and to establish a comparison of wall mechanics between ruptured and unruptured aneurysms.

The use of thoracic stent grafts for endovascular repair of abdominal aortic aneurysms

Vascular ◽  
2017 ◽  
Vol 26 (3) ◽  
pp. 278-284 ◽  
Author(s):  
VP Bastiaenen ◽  
MGJ Snoeijs ◽  
JGAM Blomjous ◽  
J Bosma ◽  
VJ Leijdekkers ◽  
...  
Keyword(s):  
Endovascular Repair ◽  
Endovascular Aneurysm Repair ◽  
Aortic Aneurysms ◽  
Type I ◽  
Stent Grafts ◽  
Aortic Neck ◽  
Abdominal Aortic ◽  
Median Diameter ◽  
Aneurysm Repair

Objectives Stent grafts for endovascular repair of infrarenal aneurysms are commercially available for aortic necks up to 32 mm in diameter. The aim of this study was to evaluate the feasibility of endovascular repair with large thoracic stent grafts in the infrarenal position to obtain adequate proximal seal in wider necks. Methods All patients who underwent endovascular aneurysm repair using thoracic stent grafts with diameters greater than 36 mm between 2012 and 2016 were included. Follow-up consisted of CT angiography after six weeks and annual duplex thereafter. Results Eleven patients with wide infrarenal aortic necks received endovascular repair with thoracic stent grafts. The median diameter of the aneurysms was 60 mm (range 52–78 mm) and the median aortic neck diameter was 37 mm (range 28–43 mm). Thoracic stent grafts were oversized by a median of 14% (range 2–43%). On completion angiography, one type I and two type II endoleaks were observed but did not require reintervention. One patient experienced graft migration with aneurysm sac expansion and needed conversion to open repair. Median follow-up time was 14 months (range 2–53 months), during which three patients died, including one aneurysm-related death. Conclusions Endovascular repair using thoracic stent grafts for patients with wide aortic necks is feasible. In these patients, the technique may be a reasonable alternative to complex endovascular repair with fenestrated, branched, or chimney grafts. However, more experience and longer follow-up are required to determine its position within the endovascular armamentarium.

Single-stage thoracic and abdominal endovascular aneurysm repair for multilevel aortic disease

Vascular ◽  
2013 ◽  
Vol 22 (1) ◽  
pp. 55-60 ◽  
Author(s):  
Makoto Samura ◽  
Nobuya Zempo ◽  
Yoshitaka Ikeda ◽  
Masaaki Hidaka ◽  
Yoshikazu Kaneda ◽  
...  
Keyword(s):  
Spinal Cord Ischemia ◽  
Endovascular Aneurysm Repair ◽  
Abdominal Aortic Aneurysms ◽  
Aortic Disease ◽  
Aortic Aneurysms ◽  
Single Stage ◽  
Type I ◽  
Abdominal Aortic ◽  
Thoracic And Abdominal ◽  
Aneurysm Repair

This investigation evaluated the results of single-stage thoracic endovascular aneurysm repair (TEVAR) and endovascular aneurysm repair (EVAR) for multilevel aortic disease in a series of nine patients. The lesions repaired included thoracic and abdominal aortic aneurysms ( n = 7) and subacute type B dissections with abdominal aortic aneurysms ( n = 2). All procedures were successfully performed, and none of the patients experienced postoperative stroke or spinal cord ischemia. The median follow-up period for these patients was 18.9 months (range 1.7–31.4 months) and none of the patients exhibited any signs of type I endoleaks or aneurysmal diameter enlargements more than 5 mm. In conclusion, single-stage TEVAR and EVAR procedures for multilevel aortic disease were found to be safe and feasible modalities for high-risk patients.

scholarly journals The Polymer-Based Technology in the Endovascular Treatment of Abdominal Aortic Aneurysms

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1196
Author(s):  
Gianmarco de Donato ◽  
Edoardo Pasqui ◽  
Claudia Panzano ◽  
Brenda Brancaccio ◽  
Gaia Grottola ◽  
...  
Keyword(s):  
Stent Graft ◽  
Endovascular Aneurysm Repair ◽  
Invasive Procedure ◽  
Aortic Disease ◽  
Aortic Aneurysms ◽  
Metallic Stent ◽  
Stent Grafts ◽  
Abdominal Aortic ◽  
Aneurysmal Neck ◽  
Aneurysm Repair

An abdominal aortic aneurysm (AAA) is a dilatation of the abdominal aorta that progressively grows until it ruptures. Treatment is typically recommended when the diameter is more than 5 cm. The EVAR (Endovascular aneurysm repair) is a minimally invasive procedure that involves the placement of an expandable stent graft within the aorta to treat aortic disease without operating directly on the aorta. For years, stent grafts’ essential design was based on metallic stent frames to support the fabric. More recently, a polymer-based technology has been proposed as an alternative method to seal AAA. This review underlines the two platforms that are based on a polymer technology: (1) the polymer-filled endobags, also known as Endovascular Aneurysm Sealing (EVAS) with Nellix stent graft; and (2) the O-ring EVAR polymer-based proximal neck sealing device, also known as an Ovation stent graft. Polymer characteristics for this particular aim, clinical applications, and durability results are hereby summarized and commented critically. The technique of inflating endobags filled with polymer to exclude the aneurysmal sac was not successful due to the lack of an adequate proximal fixation. The platform that used polymer to create a circumferential sealing of the aneurysmal neck has proven safe and effective.

scholarly journals Vascular Deformation Mapping of Abdominal Aortic Aneurysm

Tomography ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 189-201
Author(s):  
Drew J. Braet ◽  
Jonathan Eliason ◽  
Yunus Ahmed ◽  
Pieter A. J. van Bakel ◽  
Jiayang Zhong ◽  
...  
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Complex Disease ◽  
Endovascular Aneurysm Repair ◽  
Three Dimensional ◽  
Aortic Aneurysms ◽  
Maximum Diameter ◽  
Abdominal Aortic ◽  
Risk Of Rupture ◽  
Imaging Surveillance

Abdominal aortic aneurysm (AAA) is a complex disease that requires regular imaging surveillance to monitor for aneurysm stability. Current imaging surveillance techniques use maximum diameter, often assessed by computed tomography angiography (CTA), to assess risk of rupture and determine candidacy for operative repair. However, maximum diameter measurements can be variable, do not reliably predict rupture risk and future AAA growth, and may be an oversimplification of complex AAA anatomy. Vascular deformation mapping (VDM) is a recently described technique that uses deformable image registration to quantify three-dimensional changes in aortic wall geometry, which has been previously used to quantify three-dimensional (3D) growth in thoracic aortic aneurysms, but the feasibility of the VDM technique for measuring 3D growth in AAA has not yet been studied. Seven patients with infra-renal AAAs were identified and VDM was used to identify three-dimensional maps of AAA growth. In the present study, we demonstrate that VDM is able to successfully identify and quantify 3D growth (and the lack thereof) in AAAs that is not apparent from maximum diameter. Furthermore, VDM can be used to quantify growth of the excluded aneurysm sac after endovascular aneurysm repair (EVAR). VDM may be a useful adjunct for surgical planning and appears to be a sensitive modality for detecting regional growth of AAAs.

Effects of Major Endoleaks on a Stented Abdominal Aortic Aneurysm

2005 ◽  
Vol 128 (1) ◽  
pp. 59-68 ◽  
Author(s):  
Z. Li ◽  
C. Kleinstreuer
Keyword(s):  
Stent Graft ◽  
Three Dimensional ◽  
Wall Stress ◽  
Aortic Aneurysms ◽  
Type I ◽  
Abdominal Aortic ◽  
Wave Forms ◽  
Type I Endoleak ◽  
Graft Migration ◽  
The Impact

Insertion of a stent-graft into an aneurysm, especially abdominal aortic aneurysms (AAAs), is a very attractive surgical intervention; however, it is not without major postoperative complications, such as endoleaks. An endoleak is the transient accumulation of blood in the AAA cavity, which is formed by the stent-graft and AAA walls. Of the four blood pathways, a type I endoleak constitutes the major one. Thus, focusing on both proximal and distal type I endoleaks, i.e., the minute net influx of blood past the attachment points of a stent-graft into the AAA cavity, the transient three-dimensional interactions between luminal blood flow, stent-graft wall, leakage flow, and AAA wall are computationally simulated. For different type I endoleak scenarios and inlet pressure wave forms, the impact of type I endoleaks on cavity pressure, wall stress, and stent-graft migration force is analyzed. The results indicate that both proximal type I-a and distal type I-b endoleaks may cause cavity pressures close to a patient’s systemic pressure; however, with reduced pulsatility. As a result, the AAA-wall stress is elevated up to the level of a nonstented AAA and, hence, such endoleaks render the implant useless in protecting the AAA from possible rupture. Interestingly enough, the net downward force acting on the implant is significantly reduced; thus, in the presence of endoleaks, the risk of stent-graft migration may be mitigated.

Mid-Term Results of Endovascular Aneurysm Sealing in the Treatment of Abdominal Aortic Aneurysm With Unfavorable Morphology

2020 ◽  
Vol 55 (1) ◽  
pp. 39-49
Author(s):  
Łukasz Dzieciuchowicz ◽  
Jolanta Tomczak ◽  
Ewa Strauss ◽  
Grzegorz Oszkinis
Keyword(s):  
Cumulative Incidence ◽  
Graft Failure ◽  
Endovascular Aneurysm Repair ◽  
Aneurysm Rupture ◽  
Early Postoperative Period ◽  
Aortic Aneurysms ◽  
Type I ◽  
Duodenal Fistula ◽  
Abdominal Aortic ◽  
Mid Term Results

Purpose: To report mid-term results of endovascular aneurysm sealing (EVAS) of abdominal aortic aneurysms (AAA) deemed unsuitable for a standard endovascular aneurysm repair (EVAR). Methods: A prospectively maintained database of 42 patients with EVAR-unfavorable anatomy treated by EVAS combined with chimney grafts in case of the proximal AAA neck shorter than 5 mm was analyzed. Early outcomes included final angiographic result, intra- and early post-operative deaths, and complications. Mid-term outcomes included all-cause mortality (ACM), aneurysm-related mortality (ARM), patency of the stents, occurrence of endoleaks, serious complications and graft failures defined as the AAA growth of more than 5 mm, type I endoleak, occlusion of the stent-graft or chimney graft, aorto-duodenal fistula, or aneurysm rupture. Results: The procedure was completed in all patients. Twenty-eight chimney grafts were implanted in 19 patients. Patients were followed for a median of 24 months (range 12-34 months). There were 2 intraoperative ruptures and 1 patient died in an early postoperative period. The cumulative ACM was 15, 21, and 36% at 12, 24, and 36 months, respectively, and the cumulative ARM was 8, 11, and 27% at 12, 24, and 36 months, respectively. Three out of 5 aneurysm-related deaths were due to a secondary aorto-duodenal fistula. The cumulative incidence of graft failure was 20, 27, and 42% at 12, 24, and 36 months, respectively. The cumulative incidence of an endoleak was 5, 9, and 23% at 12, 24, and 36 months, respectively. The graft failure increased significantly both ACM (p = .012) and ARM (p = .00003). The implantation of chimney grafts at the initial procedure increased ARM significantly (p = .008). The presence of an endoleak did not have any significant influence on ACM and ARM. Conclusion: Patients treated with EVAS for AAAs with EVAR-unfavorable anatomy, especially those with chimney grafts, exhibit a high risk of graft failure and subsequent death.

scholarly journals Abdominal Aortic Disease: A Multicase Review

2019 ◽  
Vol 43 (1) ◽  
pp. 18-24
Author(s):  
Joshua D. Lee ◽  
Courtney Webb ◽  
Mark W. Fugate
Keyword(s):  
Patient Care ◽  
Iliac Artery ◽  
Endovascular Aneurysm Repair ◽  
Artery Aneurysm ◽  
Disease Diagnosis ◽  
Aortic Disease ◽  
Type I ◽  
Abdominal Aortic ◽  
Type I Endoleak ◽  
Vascular Laboratory

Abdominal aortic disease affects more than 3 million people per year. For vascular sonographers, imaging aortic disease can become routine. Therefore, it is necessary to expand the knowledge that we have of aortic disease, diagnosis, and treatment. We present 4 cases with new or worsening conditions diagnosed by duplex ultrasound (DUS). Our first case is a 79-year-old woman returning for surveillance of an endovascular aneurysm repair (EVAR). The DUS findings reveal an increasing abdominal aortic aneurysm (AAA) sac, with evidence of flow originating from an incomplete seal at the attachment suggesting type I endoleak. Next, is a 56-year-old man returning 1 month after type A dissection repair, now presenting with unilateral claudication. The DUS findings of the left lower extremity demonstrated an early systolic deceleration waveform, suggesting more proximal disease. Upon further imaging, an abdominal aortic dissection was identified terminating into the left internal iliac artery, causing the true lumen to be compressed. The third case was a 75-year-old man returning for follow-up of an EVAR and iliac repair. The DUS findings show an increase in iliac artery sac size and anechoic area that was filled with color Doppler flow. These findings are suggestive of type I endoleak involving the distal attachment. The last case is a 56-year-old man returning for EVAR and iliac artery repair surveillance. The common iliac artery aneurysm sac had increased in diameter and length. The distal attachment of the left iliac extension cuff terminated within the aneurysm sac, causing a type I endoleak. Accurate DUS diagnosis of aortic disease is crucial for patient care. Meticulous analysis of the vessels and surrounding structures can make a difference in diagnostic outcomes. Vascular sonographers should continually review and revise vascular laboratory protocols to increase their diagnostic accuracy and improve patient care. It is important to extend the vascular laboratory protocols when complex cases arise to better demonstrate complicated diagnoses and challenging anatomy.

scholarly journals Targeting the Extracellular Matrix in Abdominal Aortic Aneurysms Using Molecular Imaging Insights

2021 ◽  
Vol 22 (5) ◽  
pp. 2685
Author(s):  
Lisa Adams ◽  
Julia Brangsch ◽  
Bernd Hamm ◽  
Marcus R. Makowski ◽  
Sarah Keller
Keyword(s):  
Extracellular Matrix ◽  
Molecular Imaging ◽  
Molecular Targets ◽  
Abdominal Aortic Aneurysms ◽  
Aortic Aneurysms ◽  
Type I ◽  
Target Tissue ◽  
Pharmacologic Treatment ◽  
Abdominal Aortic

This review outlines recent preclinical and clinical advances in molecular imaging of abdominal aortic aneurysms (AAA) with a focus on molecular magnetic resonance imaging (MRI) of the extracellular matrix (ECM). In addition, developments in pharmacologic treatment of AAA targeting the ECM will be discussed and results from animal studies will be contrasted with clinical trials. Abdominal aortic aneurysm (AAA) is an often fatal disease without non-invasive pharmacologic treatment options. The ECM, with collagen type I and elastin as major components, is the key structural component of the aortic wall and is recognized as a target tissue for both initiation and the progression of AAA. Molecular imaging allows in vivo measurement and characterization of biological processes at the cellular and molecular level and sets forth to visualize molecular abnormalities at an early stage of disease, facilitating novel diagnostic and therapeutic pathways. By providing surrogate criteria for the in vivo evaluation of the effects of pharmacological therapies, molecular imaging techniques targeting the ECM can facilitate pharmacological drug development. In addition, molecular targets can also be used in theranostic approaches that have the potential for timely diagnosis and concurrent medical therapy. Recent successes in preclinical studies suggest future opportunities for clinical translation. However, further clinical studies are needed to validate the most promising molecular targets for human application.

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