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The Biomechanics Of Ascending Aortic Aneurysms
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Book Synopsis Biomechanics and Mechanobiology of Aneurysms by : Tim McGloughlin
Download or read book Biomechanics and Mechanobiology of Aneurysms written by Tim McGloughlin and published by Springer Science & Business Media. This book was released on 2011-09-15 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cardiovascular disease is the leading cause of morbidity and premature death of modern era medicine. It is estimated that approximately 81 million people in the United States (US) currently have one or more of the many forms of cardiovascular disease, resulting in 1 in every 2.8 deaths, or 900,000 deaths per year. 40% of all deaths in Europe are a result of cardiovascular disease in people under the age of 75. Aneurysms form a significant portion of these cardiovascular related deaths and are defined as a permanent and irreversible localised dilation of a blood vessel greater than 50% of its normal diameter. Although aneurysms can form in any blood vessel, the more lethal aneurysms develop in the cranial arteries, and in the thoracic aorta and abdominal aorta. Frequently aneurysms are undetected and if left untreated may eventually expand until rupture with very high levels of morbidity and mortality. The biomechanics and mechanobiology of aneursymal diseases are not fully understood and this monograph aims to provide new insights into aneurysm aetiology and behavior based on the most recent biomechanics research related to this important topic. The contributors to this volume bring together a unique blend of expertise in experimental, computational and tissue biomechanics relating to aneurysm behavior and enable the reader to gain a fresh understanding of key factors influencing aneurysm behavior and treatment. Biological risk factors such as tobacco smoking, sex, age, hypertension, family history and mechanobiological risk factors such as aneurysm geometry and shape as well as mechanical properties of the diseased tissues are considered in detail as are many of the diagnostic and treatment options.
Book Synopsis The Biomechanics of Ascending Aortic Aneurysms by : Evan Wener
Download or read book The Biomechanics of Ascending Aortic Aneurysms written by Evan Wener and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "An ascending aortic aneurysm is a pathologic enlargement of the ascending portion of the aorta. Comorbidities of dilation include aortic valve disease and connective tissue disorders. If the ascending aorta exceeds a threshold diameter, open heart surgery is recommended. This is a traumatic procedure and the recovery is demanding. As our population ages and with improved technologies to diagnose the disease, the number of cases will increase every year. Understanding the mechanics of ascending aortic tissue will help cardiac surgeons make timely decisions on when to intervene. There are many ways to characterize the mechanical properties of aortic tissue. In this study, we used biaxial and uniaxial tensile testing with an optical tracking system to record the Green-Lagrangian (Green strain) strain. Engineering and true stiffness values were calculated and compared along with patient characteristics. Aortas were classified by valve type as healthy, tricuspid, bicuspid type 1 and bicuspid type 2. The results show that diseased tissue does behave differently than healthy tissue indicating that a local remodeling does occurs to the aortic wall. There are also differences in the mechanics between the types of diseased valves suggesting that valve type also affects the way the aortic wall responds to the disturbed hemodynamic environment. Correlations between stiffness and patient characteristics show that no matter which experimented technique or method of stiffness calculation is used, relationships are generally conserved. The only difference is the magnitude of the elastic modulus. The conclusions drawn from the data would not change whether biaxial or uniaxial experiments were performed. However when comparing engineering and true stiffness, only 7/12 covariances were similar and therefore the conclusions are inconsistent. " --
Book Synopsis Biomechanics of Ascending Aortic Aneurysms by : Alexander Emmott
Download or read book Biomechanics of Ascending Aortic Aneurysms written by Alexander Emmott and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "The aorta is the largest artery in the body and serves as the conduit for systemic blood flow from the heart. Its central property is its passive elastic behaviour that converts fluid energy to elastic potential during systole and subsequently returns that stored potential to maintain systemic circulation during diastole. With disease the pathological remodelling of the wall can result in an impairment of its elastic function, particularly in the case of an aortic aneurysm. If left unrepaired, aortic aneurysms carry significant risk of tearing and often result in death or serious disability. Clinical guidelines for surgical intervention are based on aortic diameter thresholds, but unfortunately these criteria are insufficient and an estimated 40% of dissection and rupture cases occur at diameters below the surgical guidelines. Aortic diameter criteria do not fully relay the risk that elastic impairment and pathological remodelling contribute to dissection or rupture. Herein, this thesis tested the hypothesis that the elastic or mechanical properties of the aortic wall can be used as a marker of ascending aortic dysfunction and contribute added information beyond size to identify at-risk patients. In this work we used transesophageal echocardiography, an application of ultrasound imaging to the heart and great vessels, to assess the mechanical properties of the ascending aorta and subsequently validated this methodology with ex vivo tensile analysis on resected tissue. Specifically, we developed novel in vivo stiffness metrics termed the Cardiac Cycle Pressure Modulus (CCPM) and the Cardiac Cycle Stress Modulus (CCSM) that were compared with aortic wall histology and ex vivo stiffness and energy loss parameters that have been widely reported, previously. This approach was applied globally (i.e., circumference averaged) and regionally at four distinct foci around the aortic circumference. Global CCPM and CCSM were significantly predictive of ex vivo mechanical indices and histopathology and could be used to identify patients with adverse aortic remodelling who did not meet standard surgical criteria of ≥5.5 cm diameter. Regional analysis demonstrated that heterogeneity in CCPM and CCSM increased with medial degeneration creating uneven distribution of physiological stress in the aortic wall. Furthermore, both tensile and compressive strain patterns were observed simultaneously in neighbouring regions of some patients suggesting a more complex physio-mechanical environment than had previously been appreciated. Ultimately, this work proposes a novel assessment technique to follow patients with ascending aortic aneurysms that may provide a crucial added dimension to surgical management of patients." --
Book Synopsis Biomechanics of Human Ascending Aorta and Aneurysm Rupture Risk Assessment by : Siyu Lin
Download or read book Biomechanics of Human Ascending Aorta and Aneurysm Rupture Risk Assessment written by Siyu Lin and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ascending aortic aneurysms (AsAA) and aortic dissections are life-threatening cardiovascular diseases. The main criteria for determining surgical intervention of AsAA are the maximum diameter or the increasing annual rate of the aneurysm. The mortality of the untreated aortic dissection can be 21% to 74%, depending on the delay of hospital admission.Our study aims to characterize the biomechanical properties of the ascending aorta and propose a patient-specific approach to assess the risks of rupture. The purpose of this PhD work is multifold.On the one hand, biaxial tensile tests were performed on AsAA samples obtained from one hundred patients with surgery of AsAA. The impact on the different characteristics and risks was evaluated and cross-compared. We have shown that the risk factors of gender, age, diameter, and aortic valve disorders have a major impact on the stiffness of AsAA. On the other hand, eleven acute type A aortic dissection samples were collected. We have confirmed that the adventitia shows a significant stiffness than the intimomedial layer. Meanwhile, a rare case of AsAA associated with the quadricuspid aortic valve displays similar biomechanical properties to AsAA associated with the bicuspid aortic valve than with the tricuspid aortic valve. In order to make synthetic modeling from 3D printed aorta in 4D flow magnetic resonance imaging (MRI) study, three three-dimensional printable materials were tested to compare with an undilated aortic wall. The biomechanical properties of the 50 SH (shore stiffness) RGD450+TangoPlus is the most aorta-alike material.To conclude, from our result from one hundred patients, gender, age, diameter, and aortic valve disorders are the key to aortic stiffness.
Book Synopsis Biomechanics of the Aorta by : T. Christian Gasser
Download or read book Biomechanics of the Aorta written by T. Christian Gasser and published by Elsevier. This book was released on 2024-06-18 with total page 636 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biomechanics of the Aorta: Modelling for Patient Care is a holistic analysis of the aorta towards its biomechanical description. The book addresses topics such as physiology, clinical imaging, tissue and blood flow modeling, along with knowledge that is needed in diagnostics, aortic rupture prediction, assist surgical planning, and more. It encompasses a wide range of topics from the basic sciences (Vascular biology, Continuum mechanics, Image analysis) to clinical applications, as well as describing and presenting computational studies and experimental benches to mimic, understand and propose the best treatment of aortic pathologies. The book begins with an introduction to the fundamental aspects of the anatomy, biology and physiopathology of the aorta and proceeds to present the main computational fluid dynamic studies and biomechanical and mechanobiological models developed over the last decade. With approaches, methodologies and findings from contributors all over the world, this new volume in the Biomechanics of Living Organs series will increase understanding of aortic function as well as improve the design of medical devices and clinical interventions, including surgical procedures. Represents a comprehensive means for those involved in the aortic research and the related developments in the industry Introduces the most recent imaging technologies to characterize factors, such as aortic geometry, mechanical properties of the aortic tissue, and the local cellular activity in the vessel wall Synthesizes advances in vascular biomechanics, medical imaging and computational finite element fluid and solid models to increase understanding of aorta function
Book Synopsis Obtaining the Biomechanical Behavior of Ascending Aortic Aneurysm by Using Novel Speckle Tracking Echocardiography by : Mohammed Alreshidan
Download or read book Obtaining the Biomechanical Behavior of Ascending Aortic Aneurysm by Using Novel Speckle Tracking Echocardiography written by Mohammed Alreshidan and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Energy Loss, a Novel Biomechanical Parameter, Correlates with Aortic Aneurysm Size and Histopathology by : Jennifer Chung
Download or read book Energy Loss, a Novel Biomechanical Parameter, Correlates with Aortic Aneurysm Size and Histopathology written by Jennifer Chung and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "It is not well understood which ascending aortas will develop complications. Biomechanics may provide insights beyond the consideration of size alone, and improve risk prediction. Energy loss is a biomechanical parameter describing the relative amount of energy absorbed by the aorta during the cardiac cycle. We aim to correlate energy loss with ascending aortic aneurysm size and histopathology to elucidate the pathophysiology of aneurysm complications.Aneurysmal ascending aortic specimens were obtained during surgery. Controls were obtained from autopsy and organ donors. Biaxial tensile tests were performed on the four quadrants of the aortic ring. Energy loss was calculated using the integral of the stress-strain curve during loading and unloading. It was compared to size and the traditional biomechanical parameter, stiffness (apparent modulus of elasticity). Elastin, collagen and mucopolysaccharide content was quantified using Movat pentachrome staining of histology slides. Forty-one aortas were collected (34 aneurysmal, 7 control). Aneurysms exhibited increased stiffness (p
Book Synopsis Theoretical and Experimental Analyses of the Rupture of Ascending Thoracic Aortic Aneurysm by : Nastaran Shahmansouri
Download or read book Theoretical and Experimental Analyses of the Rupture of Ascending Thoracic Aortic Aneurysm written by Nastaran Shahmansouri and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Ascending thoracic aortic aneurysms (ATAAs) is an arterial disease which can lead to a dissection or rupture of the aorta, causing the death of the patients. Several studies have investigated the rupture mechanisms of ATAAs, however, underlying reasons behind aortic rupture (failure) have not been fully understood and further investigations are necessary. Surgical interventions used to treat this disease are associated with risks of mortality and morbidity. While size is the main clinical measure for aortic replacement surgery, there are uncertainties about the efficiency of this measure. To better guide surgical decision making, a biomechanical surrogate measure estimating ATAA wall properties is needed to better stratify patients. Understanding the biomechanical and histopathological changes associated with ascending thoracic aortic aneurysms (ATAAs), this research investigates different mechanical properties of the aorta. The rupture of pathological aortic tissue is a local phenomenon resulting from defects or tears in the vessel wall. In this work, the toughness-based rupture properties of human ATAAs have been examined. The toughness, biaxial tensile characteristics, and histological properties of aneurysmal and control ascending thoracic aortas (ATAs) were characterized from four quadrants of surgically excised aortic rings. To further explore the rupture propensity of ATAAs, the inter-correlation of the toughness properties with histological characteristics have been explored. The toughness properties were also investigated for cryopreserved and control porcine tissues.The loss factor, a surrogate measure defined as the ratio of dissipated energy to the energy absorbed during a tensile cycle, the incremental modulus, and their anisotropy index were also determined for the controlled and aneurysmal human ATAs. These parameters were compared with the media fiber compositions, the aortic diameter, and patients' age for the ATAAs associated with bicuspid aortic valve (BAV) and tricuspid aortic valve (TAV). Additionally, the variations of fiber contents through the aortic thickness and the non-linear tensile characteristic of the aortas have been examined.The results obtained suggest tissue remodeling could affect toughness and stiffness properties differently in ascending aortic aneurysms. The results propose the loss factor, which may be measured non-invasively, could be a useful surrogate measure to describe the histopathology of aneurysmal tissue and to demonstrate the differences between ATAAs with bicuspid and tricuspid aortic valve types." --
Book Synopsis Aortic Aneurysm and Aortic Dissection by : Jeffrey Shuhaiber
Download or read book Aortic Aneurysm and Aortic Dissection written by Jeffrey Shuhaiber and published by BoD – Books on Demand. This book was released on 2020-09-09 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aortic aneurysms and dissections are common problems worldwide. Although surgery outcomes are improving, etiology remains elusive and absolute methods of primary prevention remain unknown. This book addresses these areas and provides future directions for clinicians and researchers who are involved in aortic disease. It reviews diagnosis and surveillance of aortic root dilation, mycotic aortic aneurysm, and the role of human immunodeficiency virus. Written by international experts, chapters discuss such topics as animal models for abdominal aortic aneurysm, safe methods of repairing type A aortic dissection, and challenges in data image analysis. This book provides a simple framework for those who want to understand the principles of aortic aneurysm and aortic dissection repair.
Book Synopsis Calcific Aortic Valve Disease by : Elena Aikawa
Download or read book Calcific Aortic Valve Disease written by Elena Aikawa and published by BoD – Books on Demand. This book was released on 2013-06-12 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to population aging, calcific aortic valve disease (CAVD) has become the most common heart valve disease in Western countries. No therapies exist to slow this disease progression, and surgical valve replacement is the only effective treatment. Calcific Aortic Valve Disease covers the contemporary understanding of basic valve biology and the mechanisms of CAVD, provides novel insights into the genetics, proteomics, and metabolomics of CAVD, depicts new strategies in heart valve tissue engineering and regenerative medicine, and explores current treatment approaches. As we are on the verge of understanding the mechanisms of CAVD, we hope that this book will enable readers to comprehend our current knowledge and focus on the possibility of preventing disease progression in the future.
Book Synopsis Biomechanics of abdominal aortic aneurysms : an experimental approach towards a better understanding of pathological progression by : Jianhua Tong
Download or read book Biomechanics of abdominal aortic aneurysms : an experimental approach towards a better understanding of pathological progression written by Jianhua Tong and published by . This book was released on 2013 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Transport in Biological Media by : Sid M. Becker
Download or read book Transport in Biological Media written by Sid M. Becker and published by Newnes. This book was released on 2013-05-21 with total page 575 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transport in Biological Media is a solid resource of mathematical models for researchers across a broad range of scientific and engineering problems such as the effects of drug delivery, chemotherapy, or insulin intake to interpret transport experiments in areas of cutting edge biological research. A wide range of emerging theoretical and experimental mathematical methodologies are offered by biological topic to appeal to individual researchers to assist them in solving problems in their specific area of research. Researchers in biology, biophysics, biomathematics, chemistry, engineers and clinical fields specific to transport modeling will find this resource indispensible. Provides detailed mathematical model development to interpret experiments and provides current modeling practices Provides a wide range of biological and clinical applications Includes physiological descriptions of models
Book Synopsis Mechanisms of Vascular Disease by : Robert Fitridge
Download or read book Mechanisms of Vascular Disease written by Robert Fitridge and published by University of Adelaide Press. This book was released on 2011 with total page 589 pages. Available in PDF, EPUB and Kindle. Book excerpt: New updated edition first published with Cambridge University Press. This new edition includes 29 chapters on topics as diverse as pathophysiology of atherosclerosis, vascular haemodynamics, haemostasis, thrombophilia and post-amputation pain syndromes.
Book Synopsis Diagnosis, Screening and Treatment of Abdominal, Thoracoabdominal and Thoracic Aortic Aneurysms by : Reinhart Grundmann
Download or read book Diagnosis, Screening and Treatment of Abdominal, Thoracoabdominal and Thoracic Aortic Aneurysms written by Reinhart Grundmann and published by BoD – Books on Demand. This book was released on 2011-09-12 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book considers mainly diagnosis, screening, surveillance and treatment of abdominal, thoracoabdominal and thoracic aortic aneurysms. It addresses vascular and cardiothoracic surgeons and interventional radiologists, but also anyone engaged in vascular medicine. The high mortality of ruptured aneurysms certainly favors the recommendation of prophylactic repair of asymptomatic aortic aneurysms (AA) and therewith a generous screening. However, the comorbidities of these patients and their age have to be kept in mind if the efficacy and cost effectiveness of screening and prophylactic surgery should not be overestimated. The treatment recommendations which will be outlined here, have to regard on the one hand the natural course of the disease, the risk of rupture, and the life expectancy of the patient, and on the other hand the morbidity and mortality of the prophylactic surgical intervention. The book describes perioperative mortality after endovascular and open repair of AA, long-term outcome after repair, and the cost-effectiveness of treatment.
Download or read book Aortic Aneurysm written by Kaan Kırali and published by BoD – Books on Demand. This book was released on 2017-02-22 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aortic aneurysms are very silent, insidious, and sudden complicated pathologies with high incidence of sudden death. The aorta has several different parts, which are affected by aneurysmal pathology independently and separately or conjointly. Preventive medicine and determinative genetic heritage are the first steps during diagnosis and precaution. Preventive screening of the general population seems the best way for diagnosing early asymptomatic aneurysms with increased health cost. Because sudden death is the first symptom of aortic aneurysms, early interventional treatment is essential to protect fatal complications. In spite of open surgical repair which is the standard procedure, isolated or hybrid endovascular approaches are used widespread in the last decade due to reduction of procedural complications. This book is composed of the main topics on aortic aneurysms and surgical treatments to extend scientific and therapeutic perspective and vision of cardiac teams.
Download or read book Aneurysm written by Yasuo Murai and published by IntechOpen. This book was released on 2012-08-29 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book's focus is on diagnosis and treatment of intracranial aneurysm, abdominal and thoracic aortic aneurysms. It addresses neurosurgical, vascular and cardiothoracic surgeons and interventional radiologists, but also anyone engaged in vascular medicine. It presents is an effort to collect an up-to-date account of existing knowledge, involving recent developments in this field. Various experts described details of established knowledge or newly recognized advances associated with diagnosis, treatment, perioperative management and mechanism. This is the first book that deals with the whole body aneurysm, such as cerebral aneurysm, abdominal aneurysm, and splenial aneurysm and to learn the latest developments in other fields is always useful. I hope this book will be used worldwide by vascular surgeons and interventionalists enhancing their knowledge and stimulating the advancement of this field.
Book Synopsis Development of an Ex Vivo Tissue Testing System for Three Dimensional Biomechanical Analysis of Abdominal Aortic Aneurysm by : Bradley Ryan Johns
Download or read book Development of an Ex Vivo Tissue Testing System for Three Dimensional Biomechanical Analysis of Abdominal Aortic Aneurysm written by Bradley Ryan Johns and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Abdominal aortic aneurysms (AAA) are localized, progressive dilations of the aortic wall and are the 13th most common cause of death in the United States (~15,000 per year) and surgery is usually recommended when the aneurysm is 5 cm or larger in diameter. Because of this clinical parameter, previous studies of AAA biomechanics have utilized a one-dimensional analysis that focuses solely on changes in wall diameter and have attempted to model geometric changes with mathematical formulas, generally based on the LaPlace equation. This is not sufficient however, as the mechanical behavior of the tissue at sites of aneurysm have been documented as being nonlinear, anisotropic, and non-homogeneous in addition to having a complex geometry. Further, since aneurysms have been found to vary in their progression, the success of such models in predicting geometric changes leading to rupture has been minimal. Therefore, an approach to quantify the 3D changes in the wall geometry of AAA is necessary for adequate estimations of the abnormal wall stresses that occur at the site of aneurysm. The overall aim of this project was to develop an ex vivo tissue testing system that will allow for 3D biomechanical analysis of aorta specimens from small animals. More specifically, we have designed, assembled, and calibrated a computer-controlled experimental setup that allows tissue samples to be pressure loaded and imaged from multiple angles at prescribed pressure increments. We have also developed custom LabVIEW scripts to control the hardware and MATLAB scripts to produce 3D images and geometry data of the specimen at these prescribed pressure levels. Our calibration study with image phantoms revealed that percent error for curvature and diameter calculations ranged between 2-10%. Additionally, aortic wall stresses under varying pressures were calculated and compared in normal tissue samples and an aorta with an artificially induced bulge. The stress levels ranged between 96-219 kPa and 15-76kPa (under 30-150 mmHg pressure) for the artificially bulging sample and normal tissues, respectively. These results demonstrated that the novel ex vivo tissue testing system developed in the present study was capable of quantifying both surface curvature and diameter of small animal aorta specimens under a wide range of pressures, allowing for wall stress estimations and opening up the possibility of more thorough testing of experimental AAA treatments.
