AORTIC AND CORONARY FLOW AND VELOCITY PROFILES IN MAN

本申请中提出的研究有三个主要目的： (1)开发和验证第三代冠状动脉多普勒血流速度 探索；(2)扩展我们现有的第三代能力 主动脉多普勒血流速度探头使仪器具有双向 能力和(3)利用这些独特的多普勒仪器来追求 重要的生理问题。第三代多普勒探头有 几种独特的功能。通过同时采样16个等距 横穿管腔的闸门，可以得到速度分布。 此外，这些数据还可以用来测量血管直径的变化 一直都在。最后，可以计算出积分体积流量。 因为探头很轻(不到10克)和微小(3-5毫米)，所以他们 可以轻轻地吸到冠状血管或主动脉上 患者在心内直视手术时。我们的实验室在 在设计和实施这一令人兴奋的新产品方面走在了前列 技术一旦这些仪器在体外和 动物实验，我们将利用它们来探讨以下问题： (1)冠状动脉反应性充血的严重抑郁是否观察到 与静息时间增加相关的心肌肥厚患者 冠脉流量？ (2)冠脉反应性充血的抑制是早期观察到的吗 体外循环后冠脉流量增加的相关时间 心流？ (3)冠状动脉狭窄对流场有何影响？ 在障碍物下游？流场中的扰动起作用了吗？ 血管壁动脉粥样硬化性改变的发病机制 在狭窄处的下游？ (4)主动脉狭窄和主动脉瓣置换术有何影响？ 在不同条件下主动脉内的速度分布？ 此外，我们改进的第三代主动脉速度多普勒探头 将被用来允许心脏外科医生定量评估 手术中主动脉瓣反流的严重程度，最重要的是， 在手术和手术过程中持续监测升主动脉血流 术后早期。这类数据应导致实质性的 改进心内直视手术患者的术中管理 做手术。

There are three main purposes of the studies proposed in this application: (1) to develop and validate a third generation coronary Doppler velocity probe; (2) to expand the capabilities of our existing third generation aortic Doppler velocity probe to make the instrument have bi-directional capability and (3) to utilize these unique Doppler instruments to pursue important physiological questions. Third generation Doppler probes have several unique capabilities. By simultaneously sampling 16 equidistant gates across the vessel lumen, velocity profiles can be obtained. Furthermore, this data can be used to measure changes in vessel diameter continuously. Finally, integrated volumetric flow can be calculated. Because the probes are light (less than 10 grams) and tiny (3-5 mm) they can be affixed with gentle suction to coronary vessels or the aorta of patients at the time of open-heart surgery. Our laboratory is at the forefront in the design and implementation of this new exciting technology. Once these instruments have been validated with in vitro and animal experiments, we will utilize them to pursue the following questions: (1) Is the severe depression in coronary reactive hyperemia observed in patients with cardiac hypertrophy related to an increase in resting coronary flow? (2) Is the depression in coronary reactive hyperemia observed in the early period following cardiopulmonary bypass related to an increase incoronary flow? (3) What are the effects of a coronary stenoses on the flow field downstream the obstruction? Do disturbances in the flow field contribute to the pathogenesis of atherosclerotic changes in the vessel wall downstream from the stenoses? (4) What are the effects of aortic stenoses and aortic valvular prosthesis on velocity profiles in the aorta under varying conditions? In addition, our improved third generation aortic velocity Doppler probe will be utilized to permit cardiac surgeons to quantitatively assess the severity of aortic regurgitation at surgery and most importantly, to continuously monitor ascending aortic flow throughout the operative and early post operative periods. Such data should lead to substantive improvements in the intraoperative management of patients having open-heart surgery.