Biomechanics Of The Aorta

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

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.

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.

The book is written by leading experts in the field presenting an up-to-date view of the subject matter in a didactically sound manner. It presents a review of the current knowledge of the behaviour of soft tissues in the cardiovascular system under mechanical loads, and the importance of constitutive laws in understanding the underlying mechanics is highlighted. Cells are also described together with arteries, tendons and ligaments, heart, and other biological tissues of current research interest in biomechanics. This includes experimental, continuum mechanical and computational perspectives, with the emphasis on nonlinear behaviour, and the simulation of mechanical procedures such as balloon angioplasty.

Because of rapid developments in computer technology and computational techniques, advances in a wide spectrum of technologies, coupled with cross-disciplinary pursuits between technology and its application to human body processes, the field of biomechanics continues to evolve. Many areas of significant progress include dynamics of musculoskeletal systems, mechanics of hard and soft tissues, mechanics of bone remodeling, mechanics of blood and air flow, flow-prosthesis interfaces, mechanics of impact, dynamics of man-machine interaction, and more. Thus, the great breadth and significance of the field in the international scene require a well integrated set of volumes to provide a complete coverage of the exciting subject of biomechanical systems technology. World-renowned contributors tackle the latest technologies in an in-depth and readable manner. . Sample Chapter(s). Chapter 1: A Simulation Study of Hemodynamic Benefits and Optimal Control of Axial Flow Pump-Based Left Ventricular Assist. Contents: Techniques in Visualization and Evaluation of the In Vivo Microcirculation (S Ichioka); Analyzing Cardiac Biomechanics by Heart Sound (A Voss et al.); Numerical and Experimental Techniques for the Study of Biomechanics in the Arterial System (T P O''Brien et al.); and many other papers. Readership: Academics, researchers and postgraduate students in anatomy, cardiology, orthopaedic, biomechanics and surgery.

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.

This book provides a balanced presentation of the fundamental principles of cardiovascular biomechanics research, as well as its valuable clinical applications. Pursuing an integrated approach at the interface of the life sciences, physics and engineering, it also includes extensive images to explain the concepts discussed. With a focus on explaining the underlying principles, this book examines the physiology and mechanics of circulation, mechanobiology and the biomechanics of different components of the cardiovascular system, in-vivo techniques, in-vitro techniques, and the medical applications of this research. Written for undergraduate and postgraduate students and including sample problems at the end of each chapter, this interdisciplinary text provides an essential introduction to the topic. It is also an ideal reference text for researchers and clinical practitioners, and will benefit a wide range of students and researchers including engineers, physicists, biologists and clinicians who are interested in the area of cardiovascular biomechanics.

"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. " --

This textbook serves as a modern introduction to vascular biomechanics and provides the comprehensive overview of the entire vascular system that is needed to run successful vascular biomechanics simulations. It aims to provide the reader with a holistic analysis of the vascular system towards its biomechanical description and includes numerous fully through-calculated examples. Various topics covered include vascular system descriptions, vascular exchange, blood vessel mechanics, vessel tissue characterization, blood flow mechanics, and vascular tissue growth and remodeling. This textbook is ideally suited for students and researchers studying and working in classical and computational vascular biomechanics. The book could also be of interest to developers of vascular devices and experts working with the regulatory approval of biomedical simulations. Follows the principle of “learning by doing” and provides numerous fully through-calculated examples for active learning, immediate recall, and self-examination; Provides a holistic understanding of vascular functioning and the integration of information from different disciplines to enable students to use sophisticated numerical methods to simulate the response of the vascular system; Includes several case studies that integrate the presented material. Case studies address problems, such as the biomechanical rupture risk assessment of Abdominal Aortic Aneurysms, Finite Element analysis of structural and blood flow problems, the computation of wall stress and wall shear stress in the aorta.