ECHOCARDIOGRAPHIC ASSESSMENT OF MICROVASCULAR PERFUSION

微血管灌注的超声心动图评估

• 批准号: 6490285
• 负责人: KEVIN S WEI
• 金额: $ 12.66万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-01-10 至 2003-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6490285
• 关键词: aortic valve stenosis; bioimaging /biomedical imaging; clinical research; contrast media; coronary vessels; diagnosis design /evaluation; dogs; echocardiography; heart circulation; hemodynamics; human subject; microcirculation; noninvasive diagnosis; perfusion

DESCRIPTION: (Adapted from applicant's abstract) The principal investigator (P.I.) for this award application has previously been productive in developing research and clinical applications for myocardial contrast echocardiography (MCE). This past research provided the P.I. with a basic understanding of ultrasound physics, coronary physiology and perfusion imaging. MCE uses microbubbles as a contrast agent during simultaneous ultrasound imaging, and has recently developed into a unique tool for the quantification of myocardial blood flow (MBF) and myocardial blood volume (MBV). Using both intracoronary injections, and continuous intravenous infusions of micro-bubbles, MCE also has the ability to discriminate between extramyocardial and capillary sites of MBF control. An improvement in our understanding of the adaptive microcirculatory changes associated with coronary artery disease (CAD) could potentially allow earlier identification of patients with this disease. The specific aims in this proposal are therefore to assess adaptive changes in MBV, the transmural distribution of MBF, and phasic changes in MBF in the setting of CAD. Acute and chronic animal models that simulate CAD in humans, and patients undergoing coronary angiography, will be used to evaluate microvascular sites of autoregulation in the setting of CAD. In the presence of exogenous hyperemia, capillaries may collapse in the bed distal to the stenosis. The physiologic basis for this occurrence, and the basis for stenosis detection using non-invasive perfusion imaging will be assessed. The transmural distribution of flow is inhomogeneous, and is related to differences in intramyocardial pressure and oxygen demands in different myocardial layers. Determining the endocardial/epicardial distribution of MBF and MBV could provide an unique way to both detect and quantify stenosis seventy. Similarly, phasic changes in coronary blood flow are influenced by myocardial function, coronary perfusion pressure, and the state of the microcirculation. Studies using MCE to evaluate phasic flow patterns in the setting of CAD, both at rest and during exogenous pharmacologic stimulation will be performed. The ultimate goal of this research is to gain a better understanding of the coronary microcirculation that will allow improved non-invasive diagnosis of CAD. The protocols outlined above require a comprehensive understanding of myocardial microcirculatory physiology, microvascular perfusion, mathematical modeling and ultrasound physics, for which Sanjiv Kaul, M.D. will serve as mentor. Furthermore, if the hypotheses of the current proposal are correct, MCE will offer novel insights into microvascular physiology that are currently not attainable with other non-invasive imaging methods, and will provide new diagnostic modalities for Cardiology.

描述：（改编自申请人摘要） 主要研究者（P.I.）对于这个奖项的申请， 以前在开发研究和临床方面是富有成效的 心肌造影超声心动图（MCE）。过去的这个 研究提供了P.I.对超声波有基本的了解 物理学、冠状动脉生理学和灌注成像。 MCE用途 微泡作为同时超声成像期间的造影剂， 最近已经发展成为一种独特的工具， 心肌血流量（MBF）和心肌血容量（MBV）。 使用 冠状动脉内注射和持续静脉输注 微气泡，MCE也有能力区分 心肌外和毛细血管部位的MBF控制。 的改善 我们对适应性微循环变化的理解 冠状动脉疾病（CAD）患者可能会更早地 识别患有这种疾病的患者。 具体目标是 因此，建议评估MBV的适应性变化， MBF的分布，以及CAD背景下MBF的时相变化。 模拟人类CAD的急性和慢性动物模型，以及 接受冠状动脉造影术的患者，将用于评价 CAD背景下自动调节的微血管部位。 在 存在外源性充血，毛细血管可能在床上塌陷 在狭窄的远端 这种情况的生理基础，以及 使用非侵入性灌注成像进行狭窄检测的基础 将被评估。 血流的跨壁分布是不均匀的， 并且与心肌内压和氧的差异有关 不同心肌层的需求。 确定 MBF和MBV的心内膜/心外膜分布可以提供 检测和量化狭窄程度的独特方法。 同样地， 冠状动脉血流的阶段性变化受心肌 功能，冠状动脉灌注压，以及 微循环 使用MCE评价相流模式的研究 在CAD背景下，无论是在休息时还是在外源性药物治疗期间， 将进行刺激。 本研究的最终目的是更好地了解 冠状动脉微循环，这将允许改善非侵入性 CAD的诊断 上述协议需要全面的 了解心肌微循环生理学、微血管 灌注，数学建模和超声物理，其中 Sanjiv Kaul，医学博士将担任导师。 此外，如果假设 目前的建议是正确的，MCE将提供新的见解， 微血管生理学，目前无法达到与其他 非侵入性成像方法，并将提供新的诊断方式 心脏病学。