Flow-Induced Wall Pressure Under Average Resting Hemodynamic Conditions for Patient-Specific Abdominal Aortic Aneurysms

2002 ◽  
Author(s):  
Ender A. Finol ◽  
Shoreh Hajiloo ◽  
Keyvan Keyhani ◽  
David A. Vorp ◽  
Cristina H. Amon
Keyword(s):  
Imaging Techniques ◽  
Abdominal Aortic Aneurysms ◽  
Aneurysm Rupture ◽  
Aortic Aneurysms ◽  
Patient Specific ◽  
Mortality And Morbidity ◽  
Abdominal Aortic ◽  
Lethal Event ◽  
Overall Mortality

Abdominal Aortic Aneurysms (AAAs) are characterized by a continuous dilation of the infrarenal segment of the abdominal aorta. Despite significant improvements in surgical procedures and imaging techniques, the mortality and morbidity rates associated with untreated ruptured AAAs are still outrageously high. AAA disease is a health risk of significant importance since this kind of aneurysm is mostly asymptomatic until its rupture, which is frequently a lethal event with an overall mortality rate in the 80% to 90% range. From a purely biomechanical viewpoint, aneurysm rupture is a phenomenon that occurs when the mechanical stress acting on the dilating inner wall exceeds its failure strength. Since the internal mechanical forces are maintained by the dynamic action of blood flowing in the aorta, the quantification of the hemodynamics of AAAs is essential for the characterization of their biomechanical environment.

scholarly journals Patient Specific Wall Stress Analysis and Mechanical Characterization of Abdominal Aortic Aneurysms Using 4D Ultrasound

2016 ◽  
Vol 52 (5) ◽  
pp. 635-642 ◽  
Author(s):  
E.M.J. van Disseldorp ◽  
N.J. Petterson ◽  
M.C.M. Rutten ◽  
F.N. van de Vosse ◽  
M.R.H.M. van Sambeek ◽  
...  
Keyword(s):  
Stress Analysis ◽  
Mechanical Characterization ◽  
Wall Stress ◽  
Abdominal Aortic Aneurysms ◽  
Aortic Aneurysms ◽  
Patient Specific ◽  
4D Ultrasound ◽  
Abdominal Aortic

Development of an Abdominal Aortic Aneurysm Ruptures Mechanism Using a Geometric Analytical Technique

2014 ◽  
Author(s):  
A. H. Embong ◽  
A. M. Al-Jumaily ◽  
G. Mahadevan ◽  
A. Lowe ◽  
S. Sugita
Keyword(s):  
Imaging Techniques ◽  
Three Dimensional ◽  
Aneurysm Rupture ◽  
Aortic Aneurysms ◽  
Patient Specific ◽  
Analytical Technique ◽  
Abdominal Aortic ◽  
Risk Of Rupture ◽  
Wall Deformation ◽  
Rupture Mechanism

Current ultrasound approaches practice probe for diagnosing instantaneous abdominal aortic aneurysms (AAA) based on arterial tissue deformation. However, tracking the progression of potential aneurysms, and predicting the risk of rupture is based on the diameter of the aneurysm and is still an insufficient method: Larger diameter aneurysms do not always lead to ruptures, and smaller diameter aneurysms unexpectedly rupture. In order to improve diagnostic accuracy of ultrasound imaging techniques, this paper presents geometric analyses of patient-specific instant deformations as a means to develop an aneurysm rupture mechanism. Segmented AAA images were used to analyze dependent elements that contribute to a three-dimensional (3-D) aneurysm reconstructive model using proposed Patient-Specific Aneurysm Rupture Predictor (P-SARP) method. The outcomes indicate that the proposed technique has the ability to associate the distortion of wall deformation with geometric analyses. This method can positively be integrated with established ultrasound techniques for improvements in the accuracy of future diagnoses of potential AAA ruptures.

An Endoluminal Method of Hemorrhage Control and Repair of Ruptured Abdominal Aortic Aneurysms

2000 ◽  
Vol 7 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Roy K. Greenberg ◽  
Sunita D. Srivastava ◽  
Kenneth Ouriel ◽  
David Waldman ◽  
Krasnodar Ivancev ◽  
...  
Keyword(s):  
Axillary Artery ◽  
Imaging Techniques ◽  
Operative Therapy ◽  
Abdominal Aortic Aneurysms ◽  
Aneurysm Rupture ◽  
Aortic Aneurysms ◽  
Prolonged Treatment ◽  
Occlusion Balloon ◽  
Abdominal Aortic ◽  
Ruptured Abdominal Aortic Aneurysms

Purpose: To report our initial experience with endovascular grafting to treat ruptured abdominal aortic aneurysms (AAAs). Methods: Three consecutive patients with severe comorbid illnesses and symptoms of aneurysm rupture and hemodynamic instability were treated with aortomonoiliac grafts. The Z-stent—based devices were implanted with the assistance of an occlusion balloon placed in the distal descending thoracic aorta. Results: All patients survived the procedure with successfully excluded AAAs. Two patients had relatively short hospital stays (4 and 14 days), while the third required prolonged treatment for pre-existing conditions. All patients required blood transfusions; 2 developed significant coagulopathies. Definitive management was delayed significantly by imaging protocols and graft construction. Conclusions: Endovascular repair of ruptured aortic aneurysms is feasible. Proximal aortic control is readily attainable with the use of an aortic occlusion balloon placed through the left axillary artery. The absence of a laparotomy, extensive retroperitoneal dissection, and aortic cross-clamping likely contributes to patient survival; however, the delay in operative therapy to obtain adequate imaging and construct an endograft could be a hindrance to the ultimate success of this approach. The concepts of alternative aortic imaging techniques and endograft design, construction, and storage must be addressed.

scholarly journals Statistical techniques for predicting rupture risk in abdominal aortic aneurysms: A contribution based on bootstrap

2021 ◽  
Vol 104 (2) ◽  
pp. 003685042110037
Author(s):  
Félix Nieto-Palomo ◽  
María-Ángeles Pérez-Rueda ◽  
Laurentiu-Mihai Lipsa ◽  
Carlos Vaquero-Puerta ◽  
José-Alberto Vilalta-Alonso ◽  
...  
Keyword(s):  
Abdominal Aortic Aneurysms ◽  
Statistical Technique ◽  
Aneurysm Rupture ◽  
Aortic Aneurysms ◽  
Patient Specific ◽  
Rupture Risk ◽  
Bootstrap Technique ◽  
Abdominal Aortic ◽  
Pearson Coefficient ◽  
Hemodynamic Stresses

The morphometry of abdominal aortic aneurysms (AAA) has been recognized as one of the main factors that may predispose them to rupture. The need to quantify the morphometry of AAA on a patient-specific basis constitutes a valuable tool for assisting in rupture risk prediction. Previous results of this research group have determined the correlations between hemodynamic stresses and aneurysm morphometry by means of the Pearson coefficient. The present work aims to find how the AAA morphology correlates with the hemodynamic stresses acting on the arterial wall. To do so, the potential of the bootstrap technique has been explored. Bootstrap works appropriately in applications where few data are available (13 patient-specific AAA models were simulated). The methodology developed can be considered a contribution to predicting the hemodynamic stresses from the size and shape indices. The present work explores the use of a specific statistical technique (the bootstrap technique) to predict, based on morphological correlations, the patient-specific aneurysm rupture risk, provide greater understanding of this complex phenomenon that can bring about improvements in the clinical management of aneurysmatic patients. The results obtained using the bootstrap technique have greater reliability and robustness than those obtained by regression analysis using the Pearson coefficient, thus allowing to obtain more reliable results from the characteristics of the samples used, such as their small size and high variability. Additionally, it could be an indicator that other indices, such as AAA length, deformation rate, saccular index, and asymmetry, are important.

scholarly journals Early pathological characterization of murine dissecting abdominal aortic aneurysms

2018 ◽  
Vol 2 (4) ◽  
pp. 046106 ◽  
Author(s):  
Evan H. Phillips ◽  
Adam H. Lorch ◽  
Abigail C. Durkes ◽  
Craig J. Goergen
Keyword(s):  
Abdominal Aortic Aneurysms ◽  
Aortic Aneurysms ◽  
Abdominal Aortic

Transport and Mixing in Patient Specific Abdominal Aortic Aneurysms With Lagrangian Coherent Structures

2012 ◽  
Author(s):  
Amirhossein Arzani ◽  
Shawn C. Shadden
Keyword(s):  
Coherent Structures ◽  
Abdominal Aortic Aneurysms ◽  
Aortic Aneurysms ◽  
Lagrangian Coherent Structures ◽  
Patient Specific ◽  
Complex Flow ◽  
Flow Topology ◽  
Finite Time Lyapunov Exponent ◽  
Abdominal Aortic ◽  
High Gradients

Abdominal aortic aneurysms (AAA) are characterized by disturbed flow patterns, low and oscillatory wall shear stress with high gradients, increased particle residence time, and mild turbulence. Diameter is the most common metric for rupture prediction, although this metric can be unreliable. We hypothesize that understanding the flow topology and mixing inside AAA could provide useful insight into mechanisms of aneurysm growth. AAA morphology has high variability, as with AAA hemodynamics, and therefore we consider patient-specific analyses over several small to medium sized AAAs. Vortical patterns dominate AAA hemodynamics and traditional analyses based on the Eulerian fields (e.g. velocity) fail to convey the complex flow structures. The computation of finite-time Lyapunov exponent (FTLE) fields and underlying Lagrangian coherent structures (LCS) help reveal a Lagrangian template for quantifying the flow [1].

Method for Incorporating Three-Dimensional Residual Stresses Into Patient-Specific Simulations of Arteries

2013 ◽  
Author(s):  
David M. Pierce ◽  
Thomas E. Fastl ◽  
Hannah Weisbecker ◽  
Gerhard A. Holzapfel ◽  
Borja Rodriguez-Vila ◽  
...  
Keyword(s):  
Medical Imaging ◽  
Three Dimensional ◽  
Constitutive Models ◽  
Abdominal Aortic Aneurysms ◽  
Aortic Aneurysms ◽  
Patient Specific ◽  
Abdominal Aortic ◽  
Model Geometry ◽  
Reconstructed Model

Through progress in medical imaging, image analysis and finite element (FE) meshing tools it is now possible to extract patient-specific geometries from medical images of, e.g., abdominal aortic aneurysms (AAAs), and thus to study clinically relevant problems via FE simulations. Medical imaging is most often performed in vivo, and hence the reconstructed model geometry in the problem of interest will represent the in vivo state, e.g., the AAA at physiological blood pressure. However, classical continuum mechanics and FE methods assume that constitutive models and the corresponding simulations start from an unloaded, stress-free reference condition.

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