QUANTITATION OF BIOMECHANICAL DETERMINANTS OF HUMAN AAA

人类 AAA 生物力学决定因素的定量

• 批准号: 6184781
• 负责人: CHRISTOPHER K ZARINS
• 金额: $ 27.74万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-30 至 2003-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6184781
• 关键词: abdomen; age difference; aorta aneurysm; bioimaging /biomedical imaging; biomechanics; blood flow measurement; clinical research; computer simulation; digital imaging; exercise; hemodynamics; human old age (65+); human subject; magnetic resonance imaging; mathematical model; mechanical stress; pathologic process; physical model; swine; thorax; vascular resistance; vascular smooth muscle; young adult human (21-34)

Our long term objective is to quantitively define the varying hemodynamic forces which act on the human thoracoabdominal aorta resulting in biomechanical stresses and strains in the vessel wall which may over time result in mechanical failure of the aortic wall and aneurysmal enlargement. Since the infrarenal abdominal aorta is particularly prone to aneurysm formation and the thoracic aorta is resistant, we will compare the two segments of aorta to determine predisposing factors for aneurysm formation. Our hypothesis is that hemodynamic forces and cumulative biomechanical stresses and strains, along with genetic susceptibility and superimposed atherogenic and humoral factors combine to result in aortic wall tissue failure and aneurysm formation. These factors, coincide, and are magnified in the abdominal aorta making it more prone to AAA. We will characterize and contrast the structural, compositional and biomechanical properties of the abdominal and thoracic aorta in humans and determine age related changes of the aortic wall. Utilizing MR imaging techniques, we will noninvasively assess thoracic and abdominal aortic blood flow in young (20-35 year old) and old (60-75 year old) normal adults as well as in patients with AAA. We will determine the 3 dimensional pulstaile flow field and quantitate differences in aortic wall strain between the abdominal and thoracic aorta. Physical models and in vivo animal experiments will be used to validate MR measurements and to develop and validate computational methods to model and predict biomechanical stress and strain of the aortic wall. These data will be used to construct a computational model of the human thoracoabdominal aorta which characterizes the 3 D pulsatile flow environment under a wide variation of conditions, such as changes in exercise states, cardiac output and blood pressure and quantify the real time aortic wall stress and strain pattern. Similarly, we will construct a computational biomechanical model of a human abdominal aortic aneurysm which will enable calculation of cumulative aortic wall stress loads over time. This will be used for predictive modeling of tissue failure and aneurysm enlargement and will be useful to evaluate strategies for therapies aimed at altering aortic wall tissue characteristics and matrix structure as well as in evaluating treatment strategies such as aortic stent grafts and open repair of the abdominal aortic aneurysms.

我们的长期目标是定量定义对人胸动主动脉的作用的不同血液动力学，导致血管壁中的生物力学应力和菌株，这可能会随着时间的推移导致主动脉壁和动脉瘤的机械故障。 由于腹主动脉的腹主动脉特别容易发生动脉瘤形成，并且胸主动脉具有抗性，因此我们将比较主动脉的两个段以确定动脉瘤形成的倾向因子。 我们的假设是血液动力学和累积生物力学应力和菌株，以及遗传易感性以及叠加的动脉粥样硬化和体液因子结合在一起，从而导致主动脉壁组织衰竭和动脉瘤形成。 这些因素，重合并在腹主动脉中放大，使其更容易容易AAA。我们将表征和对比人类腹主动脉和胸主动脉的结构，组成和生物力学特性，并确定主动脉壁相关的年龄相关变化。利用MR成像技术，我们将在年轻人（20-35岁）和老年人（60-75岁）正常成年人以及AAA患者的年轻人（20-35岁）和老年人（60-75岁）的年轻人（20-35岁）和腹部主动脉血流中进行非侵袭性。 我们将确定3维脉冲流场，并定量腹主动脉和胸主动脉之间主动脉壁应变的差异。 物理模型和体内动物实验将用于验证MR测量值，并开发和验证计算方法，以建模和预测主动脉壁的生物力学应力和应变。这些数据将用于构建人胸动主动脉的计算模型，该计算模型在各种条件的变化（例如运动状态的变化，心脏输出和血压的变化）下表征了3 d脉冲流动环境，并量化了实时主动脉壁应力和应变模式。 同样，我们将构建人腹主动脉瘤的计算生物力学模型，该模型将随着时间的推移计算累积主动脉壁应力的计算。 这将用于对组织衰竭和动脉瘤扩大的预测建模，并有助于评估旨在改变主动脉壁组织特征和基质结构的治疗策略，以及评估诸如主动脉支架移植物和开放型腹部主动脉尿症的治疗策略。