Aortic Wall Microarchitecture and Cyclic Strain

主动脉壁微结构和循环应变

• 批准号: 6776074
• 负责人: CHRISTOPHER K ZARINS
• 金额: $ 36.16万
• 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 2008-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6776074
• 关键词: abdomen; age difference; aorta; aorta aneurysm; atherosclerotic plaque; biomaterial interface interaction; biomechanics; blood vessel prosthesis; clinical research; computer simulation; gender difference; hemodynamics; human old age (65+); human subject; magnetic resonance imaging; mathematical model; mechanical stress; morphology; morphometry; physical model; swine; thorax; vascular resistance; vascular smooth muscle; young adult human (21-34)

DESCRIPTION (provided by applicant): The human aorta is susceptible to both atherosclerotic plaque deposition and aneurysmal enlargement. While the specific causal mechanisms are unclear, biomechanical factors are thought to play an important role, particularly in the differing susceptibility of the thoracic and abdominal aorta to these degenerative changes. We developed a non-invasive magnetic resonance method to quantify aortic wall biomechanics in vivo and found that aortic wall motion and strain vary around the aortic circumference with significant local variation in aortic structure. This is consistent with clinical observations of eccentric plaque localization and focal aneurysm formation. Furthermore, aortic biomechanics are impacted by implanted endovascular devices such as stents and stent grafts which are used to treat occlusive disease and aneurysms of the aorta with unknown long term consequences. During this grant, we will relate varying aortic strain patterns measured in vivo to the 3-dimensional microarchitecture of normal porcine aortas. We will then implant endovascular aortic stents and stent grafts in experimental animals to modify aortic wall biomechanics. We will assess the acute and chronic impact on in vivo aortic wall biomechanics and long-term changes in aortic microstructure. We will utilize the same in vivo magnetic resonance imaging technique to assess aortic wall motion and cyclic strain in humans and quantitate the differences about the circumference and along the length of the aorta. We will study both young and elderly healthy volunteers in order to discern age and gender related differences in aortic wall biomechanics. These data will provide valuable insights into our understanding of the structure and compostition of the aorta in relation to biomechanical strain and will provide a means of assessing the impact on the aortic wall of interventional treatments using implanted aortic devices. Further, these studies will provide a framework to understand normal age-related and degenerative changes affecting the human aorta. Finally, it will provide a quantitative basis for application of aortic magnetic resonance imaging in larger human clinical trials involving patients with aneurysmal or occlusive disease of the aorta, both before and after endovascular treatment.

描述（由申请人提供）： 人类主动脉容易受到动脉粥样硬化斑块沉积和动脉瘤扩大的影响。虽然具体的因果机制尚不清楚，但生物力学因素被认为发挥着重要作用，特别是在胸主动脉和腹主动脉对这些退行性变化的不同易感性方面。我们开发了一种非侵入性磁共振方法来量化体内主动脉壁生物力学，发现主动脉壁运动和应变围绕主动脉圆周变化，主动脉结构有显着的局部变化。这与偏心斑块定位和局灶性动脉瘤形成的临床观察结果一致。此外，主动脉生物力学受到植入式血管内装置的影响，例如用于治疗主动脉闭塞性疾病和动脉瘤的支架和覆膜支架，其长期后果未知。 在这笔资助期间，我们将把体内测量的不同主动脉应变模式与正常猪主动脉的 3 维微结构联系起来。然后，我们将在实验动物体内植入血管内主动脉支架和覆膜支架，以改变主动脉壁的生物力学。我们将评估对体内主动脉壁生物力学和主动脉微观结构的长期变化的急性和慢性影响。我们将利用相同的体内磁共振成像技术来评估人类的主动脉壁运动和循环应变，并定量主动脉圆周和沿长度的差异。我们将研究年轻和老年健康志愿者，以辨别主动脉壁生物力学中与年龄和性别相关的差异。这些数据将为我们理解主动脉的结构和组成与生物力学应变相关提供有价值的见解，并将提供一种评估使用植入主动脉装置的介入治疗对主动脉壁影响的方法。此外，这些研究将为了解影响人类主动脉的正常年龄相关和退行性变化提供一个框架。最后，它将为主动脉磁共振成像在涉及主动脉瘤或闭塞性疾病患者的更大型人体临床试验中的应用提供定量基础，无论是在血管内治疗之前还是之后。