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Studies on Subendocardial Vulnerability to Underperfusion using a Needle-probe CCD microscope

使用针探针 CCD 显微镜研究心内膜下灌注不足的脆弱性

基本信息

批准号：
07670823
负责人：
KAJIYA Fumihiko
金额：
$ 1.47万
依托单位：
Kawasaki Medical School
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

Subendocardium is most vulnerable to underperfusion and ischemia in the myocardium. Growing experimental and clinical evidence suggests that abnormal phasic coronary flow patterns, especially to-and-fro flow motion or coronary slosh phenomenon, are associated with coronary underperfusion. It is conceivable that diameter change of coronary arterioles is associated with the coronary underperfusion and phasic flow pattern. During the past several years, important observations have been made regarding the differences in arteriolar behaviors between subepicardium and subendocardium. Most striking difference is the greater arteriolar pulsation in subendocardium than in subepicardium. Therefore, to understand the cause and effect of abnormal phasic coronary flow pattern in relation to subendocardial underperfusion, it is crucial to evaluate behaviors of both subepicardial and subendocardial arterioles during coronary underperfusion. In the present study, in open-chest anesthetized dogs, a nee … More dle-probe CCD video-microscope was employed to visualize subendocardial microcirculation. In response to a transient cessation of coronary arterial flow and reperfusion (reactive hyperemia) , the percent increase in end-diastolic diameter of subendocardial arterioles was greater than that of subepicardial arterioles. The diastolic-to-systolic vascular pulsation amplitude at the peak flow was greater in the subendocardium than subepicardium. To produce a stable condition of coronary underperfusion, which is known to enhance coronary slosh phenomenon, a newly developed coronary perfusion system was connected to the left main coronary artery. The coronary perfusion pressure could be changed to a preset level. With coronary underperfusion, both subepicardial and subendocardial arterioles showed rapid changes of their diameters, suggesting the presence of quick vascular regulation. Since vasodilation is associated with a greater pulsation in the coronary arterioles, the vasodilatory response of subendocardial arterioles to a coronary underperfusion may contribute to enhance slosh phenomenon and the process of subendocardial ischemia. Less

心内膜下心肌最易发生心肌灌注不足和缺血。越来越多的实验和临床证据表明，冠状动脉血流模式异常，尤其是往返血流运动或冠状动脉晃动现象，与冠状动脉灌注不足有关。可以想象，冠状动脉小动脉的内径变化与冠脉低灌注和时相血流模式有关。在过去的几年里，人们对心外膜下和心内膜下小动脉行为的差异进行了重要的观察。最显著的区别是心内膜下的微动脉搏动比心外膜下的大。因此，要了解冠脉血流时相模式异常与心内膜下灌注不足的关系，评价心外膜和心内膜下小动脉在冠脉灌注不足时的行为是至关重要的。在目前的研究中，在开胸麻醉的狗身上，NEE…采用多探头CCD视频显微镜观察心内膜下微循环。在冠状动脉血流和再灌流(反应性充血)短暂停止后，心内膜下小动脉舒张末内径增加的百分比大于心外膜下小动脉。心内膜下血流峰值时舒张期-收缩期血管搏动幅度大于心外膜下。为了产生一种稳定的冠状动脉欠灌注状态，即已知会增加冠状动脉晃动现象，一种新开发的冠状动脉灌流系统被连接到左冠状动脉主干。冠脉灌注压可以改变到预先设定的水平。冠状动脉灌注不足时，心外膜下小动脉和心内膜下小动脉的管径变化迅速，提示存在快速的血管调节。由于血管扩张与冠状动脉小动脉的脉动增加有关，心内膜下小动脉对冠脉灌注不足的血管扩张反应可能有助于加强晃动现象和心内膜下缺血的过程。较少