Mechanism of the effect of coronary artery stenosis on coronary flow in the dog.
Mechanism of the effect of coronary artery stenosis on coronary flow in the dog.
复制标题
冠状动脉狭窄对狗冠状动脉血流影响的机制。
DOI：
10.1016/0002-8703(75)90010-1
复制
发表时间：
1975
影响因子：
4.8
通讯作者：
K. Gould
中科院分区：
文献类型：
--
作者：
K. Lipscomb;K. Gould
在10只开胸犬的回旋支上，同时测量冠状动脉流量、主动脉压和冠脉压力，研究冠状动脉狭窄对冠状动脉血流影响的血流动力学机制，同时冠脉远端通过冠脉内注射造影剂(Hypaque-M，75%)间歇性最大限度地扩张血管。对于每个狭窄，穿过狭窄的压力梯度与通过狭窄的流量直接相关(r=0.99)，回归的斜率指示狭窄的严重程度。一个重要的观察结果是，这条回归线在零流量时并没有截断流轴，而在正流量时，这意味着对于给定的回归线斜率，压力梯度比预期的要小得多。静息状态下，随着进行性狭窄降低远端床压，远端床阻力降低，将血流维持在对照水平，直到远端床压降至60 mm以下。HG。然而，在最大充血时，远端床阻力处于固定的最小值，因此流量与远端床压成正比。因此，进行性狭窄通过以下方式降低充血与静息血流的比率：(1)使血管扩张储备用于维持静息血流，减少可用于充血的储备；(2)相对较大幅度地降低远端床压以减少流量的增加。这项研究对进行性狭窄最初限制最大充血流量的已知事实提供了血流动力学解释，只有当这一流量几乎降至静息水平时，静息流量才会下降。
The hemodynamic mechanism of the effect of coronary artery stenosis on coronary flow was studied in the circumflex artery of 10 open-chest dogs by simultaneously measuring coronary flow, aortic pressure, and coronary artery pressure distal to an adjustable constrictor; while the distal coronary bed was intermittently maximally vasodilated by intracoronary injections of angiographic contrast media (Hypaque-M, 75 per cent). For each stenosis, the pressure gradient across the stenosis varied directly with the flow through the stenosis (r = 0.99), the slope of the regression indicating the severity of the stenosis. An important observation was that this regression line did not intercept the flow axis at zero flow, but at a positive flow, meaning that for a given regression line slope the pressure gradient was much less than expected. At rest, distal bed resistance decreased as progressive stenosis lowered the distal bed pressure, maintaining flow at control level until the distal bed pressure dropped below 60 mm. Hg. However, at maximum hyperemia, distal bed resistance was at a fixed minimum value such that flow was directly proportional to distal bed pressure. Hence, progressive stenosis decreased the ratio of hyperemic to resting flow by: (1) causing the vasodilatory reserve to be used to maintain resting flow, decreasing that available for hyperemia, and (2) dropping the distal bed pressure relatively more for smaller increases in flow. This study provides a hemodynamic explanation for the known fact that progressive stenosis initially limits the maximum hyperemic flow, and only after this flow is decreased almost to resting level, does resting flow fall.