Development and 3D Finite Element Implementation of a Multiaxial Constitutive Relation for Abdominal Aortic Aneurysms

2004 ◽  
Author(s):  
Jonathan Vande Geest ◽  
Ajay Bohra ◽  
Wei Sun ◽  
Elena Di Martino ◽  
Michael S. Sacks ◽  
...  
Keyword(s):  
Abdominal Aortic Aneurysms ◽  
Aortic Aneurysms ◽  
Western World ◽  
Infrarenal Aorta ◽  
3D Finite Element ◽  
Finite Element Implementation ◽  
The Past ◽  
Abdominal Aortic ◽  
The Us ◽  
Significant Disease

Abdominal aortic aneurysm (AAA), a localized dilation of the infrarenal aorta, represents a significant disease in the western population. There are approximately 200,000 patients in the US and 500,000 patients worldwide diagnosed with AAAs every year (Bosch, et al. 2001), and rupture of AAAs currently ranks as the 13th leading cause of death in the US. (Silverberg and Lubera 1987) In the past 30 years, the diagnosis of AAA has tripled in the Western world, and this will likely increase in the coming years as the average age of the population is increasing. (Bosch, et al. 2001)

Improvements in Rupture Prediction of Abdominal Aortic Aneurysms Using Local Mechanical Property Estimation Obtained From ECG-Gated Computed Tomography

2010 ◽  
Author(s):  
Áine Tierney ◽  
Anthony Callanan ◽  
Tim M. McGloughlin
Keyword(s):  
Computed Tomography ◽  
Abdominal Aortic Aneurysms ◽  
Common Type ◽  
Aortic Aneurysms ◽  
Diagnostic Tools ◽  
The Past ◽  
Property Estimation ◽  
Abdominal Aortic ◽  
The Us ◽  
Local Mechanical Property

Cardiovascular disease concerns any disease which affects the heart or blood vessels. Aneurysms account for a significant portion of these cardiovascular diseases. The most common type of aneurysm is abdominal aortic aneurysm (AAA) which affects up to 5% of the population over the age of 55. AAA is a focal balloon like dilation of the terminal aorta that occurs gradually over a span of years [1]. There are approximately 200,000 patients in the US and 500,000 patients worldwide diagnosed with AAA each year [2]. The incidences of AAA’s has increased largely during the past two decades due in part to the aging demographic, the rise in the number of smokers, the introduction of screening programmes and improved diagnostic tools [3].

Development of a Thrombus Mimic in Abdominal Aortic Aneurysms

2007 ◽  
Author(s):  
John H. Ashton ◽  
Jonathan P. Vande Geest
Keyword(s):  
United States ◽  
Cause Of Death ◽  
Growth And Development ◽  
Abdominal Aortic Aneurysms ◽  
The United States ◽  
Aortic Aneurysms ◽  
Western World ◽  
Abdominal Aortic ◽  
Significant Disease

Abdominal aortic aneurysms (AAAs) represent a significant disease in the western world as rupture of AAA is currently the 15th leading cause of death in the United States [1,2]. The rate of incidence of this disease is also thought to be increasing given the aging population. While AAA rupture is attributed to the gradual weakening of the wall, the mechanisms of aneurysm initiation, growth, and development remain relatively unclear. The role of biomechanics in the diagnosis and prevention of AAA rupture has been reported [3].

On the Uptake of Ultrasmall Superparamagnetic Particles of Iron Oxide and Biomechanical Wall Stress in Abdominal Aortic Aneurysms

2012 ◽  
Author(s):  
Barry Doyle ◽  
Jennifer Richards ◽  
Scott Semple ◽  
Tom MacGillivray ◽  
Calum Gray ◽  
...  
Keyword(s):  
Wall Stress ◽  
Inflammatory Cells ◽  
Abdominal Aortic Aneurysms ◽  
Aortic Aneurysms ◽  
Western World ◽  
Important Work ◽  
General Belief ◽  
Abdominal Aortic ◽  
The Us ◽  
Improved Methods

Abdominal aortic aneurysms (AAAs) remain a significant cause of death in the Western world with over 15,000 deaths per year in the US linked to AAA rupture. There is a general belief among the clinical and engineering community that improved methods of risk prediction are needed. The growth and expansion of AAAs over time is thought to be associated with the mechanobiological interactions within the diseased AAA wall. The stresses and strains induced in the wall by the internal blood pressure trigger increased protease activity and turnover of the extracellular matrix (ECM), thus enabling degradation and expansion of the wall. Inflammatory cells also control collagen synthesis and inflammation can reduce the tensile strength of the wall, thus contributing to the likelihood of rupture. Recently, important work by Richards et al. [1] showed that AAAs with specific sites of focal inflammation have threefold higher growth rates than AAAs with non-specific inflammation.

A Relation Between Particle Hemodynamics and Intraluminal Thrombus Formation in Abdominal Aortic Aneurysms

2009 ◽  
Author(s):  
Christopher A. Basciano ◽  
Julie H. Y. Ng ◽  
Ender A. Finol ◽  
Clement Kleinstreuer
Keyword(s):  
Particle Deposition ◽  
Thrombus Formation ◽  
Abdominal Aortic Aneurysms ◽  
Aortic Aneurysms ◽  
Blood Proteins ◽  
Intraluminal Thrombus ◽  
Abdominal Aortic ◽  
Cellular Debris ◽  
The Us ◽  
Normal Diameter

Abdominal aortic aneurysms (AAAs) are local dilations of the aorta below the renal arteries where the lumen diameter is ≥ 1.5 times the normal diameter of the healthy blood vessel. Ruptured aneurysms are the 13th leading cause of death in the US [1]. In approximately 75% of all AAAs, a particle-deposition layer forms adjacent to the arterial wall within the lumen called the intra-luminal thrombus (ILT). The thrombus composition has been shown to be a fibrin structure composed of blood cells, platelets, blood proteins, and other cellular debris [2]. Additionally, Yamazumi et al. [3] have presented data that suggest AAA morphology is associated with an elevated state of blood coagulation and fibrinolysis within the aneurysm.

Use of the Photoelastic Method to Determine the Wall Stress in Realistic Abdominal Aortic Aneurysm Models

2011 ◽  
Author(s):  
Barry J. Doyle ◽  
Anthony Callanan ◽  
John Killion ◽  
Timothy M. McGloughlin
Keyword(s):  
Wall Stress ◽  
Aortic Aneurysms ◽  
Maximum Diameter ◽  
Patient Specific ◽  
Western World ◽  
Photoelastic Method ◽  
Element Analysis ◽  
Abdominal Aortic ◽  
The Us ◽  
Numerical Tools

Abdominal aortic aneurysms (AAAs) remain a significant cause of death in the Western world with over 15,000 deaths per year in the US linked to AAA rupture. Recent research [1] has questioned the use of maximum diameter as a definitive risk parameter as it is now believed that alternative factors may be important in rupture-prediction. Wall stress was shown to be a better predictor than diameter of rupture [1], with biomechanics-based rupture indices [2,3] and asymmetry also reported to have potential clinical applicability [4]. However, the majority of numerical methods used to form these alternative rupture parameters are without rigorous experimental validation, and therefore may not be as accurate as believed. Validated experiments are required in order to convince the clinical community of the worth of numerical tools such as finite element analysis (FEA) in AAA risk-prediction. Strain gauges have been used in the past to determine the strain on an AAA [5], however, the photoelastic method has also proved to be a useful tool in AAA biomechanics [6]. This paper examines the approach using three medium-sized patient-specific AAA cases at realistic pressure loadings.

Towards the Prediction and Minimization of Device Failure for Endolvascular Grafts in Abdominal Aortic Aneurysms

2007 ◽  
Author(s):  
Ron Layman ◽  
Samy Missoum ◽  
Jonathan Vande Geest
Keyword(s):  
United States ◽  
Abdominal Aortic Aneurysm ◽  
Critical Diameter ◽  
Abdominal Aortic Aneurysms ◽  
The United States ◽  
Aortic Aneurysms ◽  
Infrarenal Aorta ◽  
Device Failure ◽  
Clinical Challenge ◽  
Abdominal Aortic

The local dilation of the infrarenal aorta, termed an abdominal aortic aneurysm (AAA), occurs over several years and may eventually lead to rupture, an event currently ranked the 15th leading cause of death in the United States [1, 2]. AAA can often remain quiescent and asymptomatic, making the diagnosis and treatment of AAA patients a clinical challenge. For patients whose AAAs dilate to a critical diameter there are two standard treatments: open surgical resection and endovascular repair (EVAR). EVAR involves inserting an endovascular graft into the aneurysm to prevent pressurization of the AAA cavity.

Morphometry and Classification in Abdominal Aortic Aneurysms: Patient Selection for Endovascular and Open Surgery

1997 ◽  
Vol 4 (1) ◽  
pp. 39-44 ◽  
Author(s):  
Hardy Schumacher ◽  
Hans H. Eckstein ◽  
Friedrich Kallinowski ◽  
Jens Rainer Allenberg
Keyword(s):  
Patient Selection ◽  
Abdominal Aortic Aneurysms ◽  
Aortic Aneurysms ◽  
Type I ◽  
Infrarenal Aorta ◽  
Iliac Arteries ◽  
Proximal Neck ◽  
Aorta Aneurysm ◽  
Abdominal Aortic ◽  
Selection For

Purpose: To evaluate the anatomic morphology of abdominal aortic aneurysms (AAAs) and compose a classification system to facilitate patient selection for endovascular graft (EVG) repair. Methods: Data on 242 consecutive AAA patients evaluated on a nonemergent basis in a 3.5-year period to July 1996 were prospectively entered into a registry. Patients were examined using sequential intravenous spiral computed tomographic angiography and intraarterial digital subtraction angiography. The data collected and analyzed included: diameters of the supra- and infrarenal aorta, aneurysm, aortoiliac bifurcation, and iliac arteries; lengths of the proximal neck, distal cuff, and aneurysm; degrees of iliac artery tortuosity; and occlusion of the visceral, renal, or iliac arteries. Results: The 242 aneurysms could be easily grouped into three distinctive categories related to the extent of the aneurysmal disease. Type I AAAs (11.2%) had nondilated, thrombus-free infrarenal (15 mm) necks and distal (10 mm) cuffs appropriate for EVG anchoring. In type II and its subgroups (72.3%), a sufficient proximal neck was present, but the aneurysm extended into the iliac arteries; 56% of these were eligible for a bifurcated endograft. In type III (16.5%), a sufficient proximal neck was missing, independent of distal involvement. In all, 51.7% were good EVG candidates based on AAA morphology. Taking into consideration relevant concomitant vascular diseases, proximal iliac kinking, and iliac, renal, or visceral occlusive disease, only 30.2% of the population were potential candidates for an efficient and secure EVG repair using the devices currently available. Conclusions: In contrast to classical open repair, detailed preoperative measurements are recommended for EVG planning. The use of liberal EVG indications may lead to a higher incidence of complications, whereas restrictive morphology-based selection criteria may offer excellent results.

scholarly journals Management and outcomes of symptomatic abdominal aortic aneurysms during the past 20 years

2017 ◽  
Vol 66 (6) ◽  
pp. 1679-1685 ◽  
Author(s):  
Venita Chandra ◽  
Karen Trang ◽  
Whitt Virgin-Downey ◽  
Ken Tran ◽  
E. John Harris ◽  
...  
Keyword(s):  
Abdominal Aortic Aneurysms ◽  
Aortic Aneurysms ◽  
The Past ◽  
Abdominal Aortic

The Development of Physiological Compliant Abdominal Aortic Aneurysm Models for In Vitro Flow Studies

2009 ◽  
Author(s):  
Timothy J. Corbett ◽  
Barry J. Doyle ◽  
Anthony Callanan ◽  
Tim M. McGloughlin
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Material Properties ◽  
Abdominal Aortic Aneurysms ◽  
Aortic Aneurysms ◽  
Flow Loop ◽  
The Past ◽  
Abdominal Aortic

A vast amount of experimental research has been undertaken in the past decade to investigate different aspects of preoperative and postoperative abdominal aortic aneurysms (AAAs). Much of this research has been based on the use of mock arteries in an in vitro flow loop to mimic the behaviour of the abdominal aorta in vivo [1]. These models should be reproducible, have consistent material properties, consistent thickness and be physiological in behaviour.

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