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速度 （2）扩展我们现有的第三代 主动脉多普勒流速探头，使仪器具有双向 能力和（3）利用这些独特的多普勒仪器， 重要的生理问题 第三代多普勒探测器 一些独特的能力。 通过同时采样16个等距 门穿过血管腔，可以获得速度分布。 此外，该数据可用于测量血管直径的变化 不断地。 最后，可以计算积分体积流量。 由于探针很轻（小于10克）和微小（3-5毫米）， 可以通过温和的抽吸固定在冠状血管或主动脉上， 患者在心脏直视手术时。 我们的实验室位于 在设计和实施这一新的令人兴奋的前沿 技术. 一旦这些仪器通过体外和 动物实验，我们将利用它们来探讨以下问题： (1)是否观察到冠状动脉反应性充血的严重抑郁， 与静息增加相关的心脏肥大患者 冠状动脉血流 (2)冠状动脉反应性充血的抑制是否在早期观察到 心肺转流术后一段时间与冠状动脉增加有关 流动？ (3)冠状动脉狭窄对血流场有什么影响 下游的障碍物吗 流场中的扰动是否有助于 血管壁动脉粥样硬化的发病机制 在狭窄处的下游 (4)主动脉瓣狭窄和人工主动脉瓣有什么影响 在不同条件下主动脉的流速分布 此外，我们改进的第三代主动脉流速多普勒探头 将用于允许心脏外科医生定量评估 手术时主动脉瓣返流的严重程度，最重要的是， 在整个手术过程中持续监测升主动脉血流， 术后早期。 这些数据应导致实质性的 心脏直视手术患者术中管理的改进 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.