Estimation of Patient-Specific 3D In Vivo Abdominal Aortic Aneurysm Strain

2013 ◽  
Author(s):  
Samarth S. Raut ◽  
Anirban Jana ◽  
Satish C. Muluk ◽  
Mark Doyle ◽  
Robert W. Biederman ◽  
...  
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Surgical Intervention ◽  
Smoking History ◽  
Patient Specific ◽  
Abdominal Aortic ◽  
Risk Of Rupture ◽  
Scientific Approach ◽  
Intravascular Devices

Abdominal Aortic Aneurysm (AAA) is a localized permanent dilatation occurring in abdominal region of the aorta. Nearly 8% of the population above 65 years old is diagnosed with this disease [1], which has been shown to be associated with smoking history, heredity, and male gender. As it is asymptomatic, vascular surgeons may opt for surgical intervention or follow a wait-and-watch strategy if their assessment of the risk of rupture is low. During surgical intervention grafts are placed inside the aorta. Design of such intravascular devices as well as monitoring the progression of the disease by means of scientific approach may benefit from information on the strains that occur in the aneurysmatic region at different instances due to cyclic internal pressurization during cardiac cycle.

Intraluminal thrombus and risk of rupture in patient specific abdominal aortic aneurysm – FSI modelling

2009 ◽  
Vol 12 (1) ◽  
pp. 73-81 ◽  
Author(s):  
Danny Bluestein ◽  
Kris Dumont ◽  
Matthieu De Beule ◽  
John Ricotta ◽  
Paul Impellizzeri ◽  
...  
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Patient Specific ◽  
Intraluminal Thrombus ◽  
Abdominal Aortic ◽  
Risk Of Rupture

Abdominal Aortic Aneurysm Risk of Rupture: Patient-Specific FSI Simulations Using Anisotropic Model

2008 ◽  
Vol 131 (3) ◽  
Author(s):  
Peter Rissland ◽  
Yared Alemu ◽  
Shmuel Einav ◽  
John Ricotta ◽  
Danny Bluestein
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Anisotropic Material ◽  
Isotropic Material ◽  
Material Model ◽  
Patient Specific ◽  
Anisotropic Model ◽  
Material Models ◽  
Abdominal Aortic ◽  
Risk Of Rupture

Abdominal aortic aneurysm (AAA) rupture represents a major cardiovascular risk, combining complex vascular mechanisms weakening the abdominal artery wall coupled with hemodynamic forces exerted on the arterial wall. At present, a reliable method to predict AAA rupture is not available. Recent studies have introduced fluid structure interaction (FSI) simulations using isotropic wall properties to map regions of stress concentrations developing in the aneurismal wall as a much better alternative to the current clinical criterion, which is based on the AAA diameter alone. A new anisotropic material model of AAA that closely matches observed biomechanical AAA material properties was applied to FSI simulations of patient-specific AAA geometries in order to develop a more reliable predictor for its risk of rupture. Each patient-specific geometry was studied with and without an intraluminal thrombus (ILT) using two material models—the more commonly used isotropic material model and an anisotropic material model—to delineate the ILT contribution and the dependence of stress distribution developing within the aneurismal wall on the material model employed. Our results clearly indicate larger stress values for the anisotropic material model and a broader range of stress values as compared to the isotropic material, indicating that the latter may underestimate the risk of rupture. While the locations of high and low stresses are consistent in both material models, the differences between the anisotropic and isotropic models become pronounced at large values of strain—a range that becomes critical when the AAA risk of rupture is imminent. As the anisotropic model more closely matches the biomechanical behavior of the AAA wall and resolves directional strength ambiguities, we conclude that it offers a more reliable predictor of AAA risk of rupture.

A Fluid Structure Interaction Approach for Patient Based Abdominal Aortic Aneurysm Rupture Risk Prediction

2010 ◽  
Author(s):  
Michalis Xenos ◽  
Suraj Rambhia ◽  
Yared Alemu ◽  
Shmuel Einav ◽  
John J. Ricotta ◽  
...  
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Fluid Structure Interaction ◽  
Patient Specific ◽  
Rupture Risk ◽  
Material Models ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Abdominal Aortic ◽  
Risk Of Rupture

Fluid structure interaction (FSI) simulations of patient-specific fusiform non-ruptured and contained ruptured Abdominal Aortic Aneurysm (AAA) geometries were conducted. The goals were: (1) to test the ability of our FSI methodology to predict the location of rupture, by correlating the high wall stress regions with the rupture location, (2) estimate the state of the pathological condition by calculating the ruptured potential index (RPI) of the AAA and (3) predict the disease progression by comparing healthy and pathological aortas. The patient specific AAA FSI simulations were carried out with advanced constitutive material models of the various components of AAA, including models that describe wall anisotropy based on collagen fibers orientation within the arterial wall, structural strength of the aorta, intraluminal thrombus (ILT), and embedded calcifications. The anisotropic material model used to describe the wall properties closely correlated with experimental results of AAA specimens. The results demonstrate that the anisotropic wall simulations showed higher peak wall stresses as compared to isotropic material models, indicating that the latter may underestimate the AAA risk of rupture. The ILT appeared to provide a cushioning effect reducing the stresses, while small calcifications (small-Ca) appeared to weaken the wall and contribute to the rupture risk. FSI simulations with ruptured AAA demonstrated that the location of the maximal wall stresses and RPI overlap the actual rupture region.

An Automated Methdology for Investigating the Correlation Between Abdominal Aortic Aneurysm Wall Stress and Risk of Rupture

2001 ◽  
Author(s):  
Madhavan L. Raghavan ◽  
Mark F. Fillinger ◽  
Steven P. Marra ◽  
Francis E. Kennedy
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Wall Stress ◽  
Aneurysm Rupture ◽  
Aneurysm Wall ◽  
Abdominal Aortic ◽  
Risk Of Rupture ◽  
Scan Data ◽  
Biomechanical Approach

Abstract Clinical experience with regard to predicting abdominal aortic aneurysm (AAA) rupture has shown that although AAA diameter is a good indicator, there are likely other risk factors. Some researchers have explored a biomechanical approach to predicting aneurysm rupture risk [1,2] based on the hypothesis that aneurysm rupture occurs when the mechanical stresses in the aortic wall exceed the wall failure strength. Therefore, knowledge of wall stresses in a particular AAA may help identify impending rupture. Recently, researchers have used patients’ abdominal CT scan data and blood pressure to estimate in-vivo AAA wall stresses [3]. In the present project, an improved automated methodology is used to predict AAA wall stress. The underlying correlation between mechanical stress and aneurysm wall rupture is also investigated.

Current evidence and prospects for medical treatment of abdominal aortic aneurysms

VASA ◽  
2005 ◽  
Vol 34 (4) ◽  
pp. 217-223 ◽  
Author(s):  
Diehm ◽  
Schmidli ◽  
Dai-Do ◽  
Baumgartner
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Medical Treatment ◽  
Endovascular Treatment ◽  
Abdominal Aortic Aneurysms ◽  
Aortic Aneurysms ◽  
Current Evidence ◽  
Significant Morbidity ◽  
Abdominal Aortic ◽  
Risk Of Rupture

Abdominal aortic aneurysm (AAA) is a potentially fatal condition with risk of rupture increasing as maximum AAA diameter increases. It is agreed upon that open surgical or endovascular treatment is indicated if maximum AAA diameter exceeds 5 to 5.5cm. Continuing aneurysmal degeneration of aortoiliac arteries accounts for significant morbidity, especially in patients undergoing endovascular AAA repair. Purpose of this review is to give an overview of the current evidence of medical treatment of AAA and describe prospects of potential pharmacological approaches towards prevention of aneurysmal degeneration of small AAAs and to highlight possible adjunctive medical treatment approaches after open surgical or endovascular AAA therapy.

Gender differences in abdominal aortic aneurysm therapy – a systematic review

VASA ◽  
2018 ◽  
Vol 47 (4) ◽  
pp. 267-272 ◽  
Author(s):  
Konstanze Stoberock ◽  
Tilo Kölbel ◽  
Gülsen Atlihan ◽  
Eike Sebastian Debus ◽  
Nikolaos Tsilimparis ◽  
...  
Keyword(s):  
Gender Differences ◽  
Abdominal Aortic Aneurysm ◽  
Survival Rate ◽  
Aortic Aneurysm ◽  
Endovascular Treatment ◽  
Aortic Aneurysms ◽  
Lower Survival Rate ◽  
Lower Survival ◽  
Abdominal Aortic ◽  
Risk Of Rupture

Abstract. This article analyses if and to what extent gender differences exist in abdominal aortic aneurysm (AAA) therapy. For this purpose Medline (PubMed) was searched from January 1999 to January 2018. Keywords were: “abdominal aortic aneurysm”, “gender”, “prevalence”, “EVAR”, and “open surgery of abdominal aortic aneurysm”. Regardless of open or endovascular treatment of abdominal aortic aneurysms, women have a higher rate of complications and longer hospitalizations compared to men. The majority of studies showed that women have a lower survival rate for surgical and endovascular treatment of abdominal aneurysms after both elective and emergency interventions. Women receive less surgical/interventional and protective medical treatment. Women seem to have a higher risk of rupture, a lower survival rate in AAA, and a higher rate of complications, regardless of endovascular or open treatment. The gender differences may be due to a higher age of women at diagnosis and therapy associated with higher comorbidity, but also because of genetic, hormonal, anatomical, biological, and socio-cultural differences. Strategies for treatment in female patients must be further defined to optimize outcome.

scholarly journals Comparison of open versus endovascular surgical treatment of abdominal aortic aneurysm

2020 ◽  
Vol 6 (3) ◽  
pp. 477-480
Author(s):  
Sabine Kischkel ◽  
Carsten M. Bünger
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Treatment Options ◽  
Prosthetic Graft ◽  
Healthcare Research ◽  
Vascular Medicine ◽  
Related Complication ◽  
Abdominal Aortic ◽  
Open Aortic Repair ◽  
Risk Of Rupture

AbstractAbdominal aortic aneurysm (AAA) is a common condition of increasing prevalence, particularly among older men. An AAA is defined as a permanent dilation of the abdominal aorta, with a diameter greater than 30 mm or a diameter greater than 50% of the aortic diameter at the level of the diaphragm. As the size of the aneurysm increases, so does the risk of rupture. Therefore, prophylactic repair with insertion of a prosthetic graft is offered. Since 1951 traditional open aneurysm repair (OAR) was reported and minimally invasive endovascular repair (EVAR) was first reported in 1986. Data from four randomized controlled trials (EVAR-1, DREAM, OVER, ACE) for abdominal aortic aneurysm, which enrolled almost 3000 patients, in a period from 1999 to 2008, were summarized. In addition, registry databases on the treatment of AAA of average 4000 patients per year, based from 2015 to 2018 of the German Institute for Vascular Medicine Healthcare Research of the German Society for Vascular Surgery and Vascular Medicine, were compared. The EVAR procedure for AAA showed a lower risk of perioperative mortality but was associated with a higher cardiovascular and aneurysm-related complication rate. In particular, patients aged 80 years or older benefited from EVAR since the 30-day mortality of patients receiving OAR was higher. In mid-term and long-term follow-up there were no differences in survival after endovascular and open aortic repair. Overall, it depends on the respective underlying disease and anatomy which of the two approaches is to be preferred. In conclusion, both treatment options can be considered as equal and can be offered to patients.

Surviving an abdominal aortic aneurysm type II endoleak rupture without surgical intervention

Vascular ◽  
2014 ◽  
Vol 23 (2) ◽  
pp. 201-203 ◽  
Author(s):  
Jeremy C Smith ◽  
Stuart R Walker
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Natural History ◽  
Endovascular Repair ◽  
Surgical Intervention ◽  
Type Ii ◽  
Ruptured Abdominal Aortic Aneurysm ◽  
Type Ii Endoleak ◽  
Abdominal Aortic

We describe a patient who survived a ruptured abdominal aortic aneurysm without any surgical intervention. The patient had previously had endovascular repair of the aneurysm and surveillance of a stable persistent type II endoleak. This case highlights the difficulties surrounding type II endoleak, its natural history, and the ongoing controversies of its management.

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