McDonough K H, Dunn R B, Griggs D M
Am J Physiol. 1984 Apr;246(4 Pt 2):H601-7. doi: 10.1152/ajpheart.1984.246.4.H601.
The distribution of the coronary collateral circulation is an important determinant of the myocardial response to acute coronary artery occlusion. The dog shows an unequal response across the ventricular wall, whereas the pig seems to have more uniform transmural changes. This study was undertaken to compare the metabolic and blood flow response in pigs and dogs to acute occlusion of the circumflex artery. Microspheres (8-10 micron) were used to determine control blood flow and flow 5 min after occlusion. A transmural tissue sample from the center of the ischemic zone was taken at 8 min after occlusion, and inner, middle, and outer layers were analyzed for high-energy phosphates and lactate. The remainder of the heart was analyzed for microsphere distribution. The epicardium in the dog showed less severe damage than the subendocardium. High-energy phosphates were higher and lactate lower in this region. In the pig high-energy phosphates and lactate were the same in the subepicardium and subendocardium. Blood flow to regions surrounding the central ischemic zone in pigs was generally uniform across the ventricular wall or greater in the inner wall than in the outer wall. These results verify that dogs as a group have a greater subepicardial protection during coronary artery occlusion. Pigs, however, demonstrate uniform ischemia or even slightly less severe ischemia in the subendocardium in regions of restricted blood flow.
冠状动脉侧支循环的分布是心肌对急性冠状动脉闭塞反应的一个重要决定因素。狗在心室壁上的反应不均等，而猪似乎有更均匀的透壁变化。本研究旨在比较猪和狗对左旋支动脉急性闭塞的代谢和血流反应。使用微球（8 - 10微米）来测定对照血流和闭塞后5分钟的血流。在闭塞后8分钟从缺血区中心采集透壁组织样本，分析内层、中层和外层的高能磷酸盐和乳酸。对心脏其余部分进行微球分布分析。狗的心外膜显示出比心内膜较轻的损伤。该区域的高能磷酸盐含量较高，乳酸含量较低。在猪中，心外膜下和心内膜下的高能磷酸盐和乳酸含量相同。猪的中央缺血区周围区域的血流在心室壁上通常是均匀的，或者在内壁比在外壁更大。这些结果证实，作为一个群体，狗在冠状动脉闭塞期间有更大的心外膜保护作用。然而，在血流受限的区域，猪的心内膜显示出均匀的缺血，甚至缺血程度略轻。
