Mueller T M, Tomanek R J, Kerber R E, Marcus M L
Am J Physiol. 1980 Dec;239(6):H731-5. doi: 10.1152/ajpheart.1980.239.6.H731.
Chronic hypertension increases the risk of myocardial infarction and the morbidity and mortality associated with it. Although accelerated atherosclerosis is partially responsible, other abnormalities in the coronary circulation associated with hypertension, such as decreased coronary vascular capacity and capillary density, could also contribute. To evaluate the effects of these nonatherosclerotic abnormalities, we produced sudden coronary occlusion in nine chronically hypertensive dogs. The mean aortic pressure and left ventricular mass were about 50% greater in hypertensive dogs than in the nine controls. Before occlusion and 5 min and 49 h after occlusion, myocardial blood flow was measured with tracer microspheres. Also, the extent of infarction in selected myocardial segments was quantified histologically. We found that coronary occlusion reduced flows to a similar extent, and that, over a 48-h period, collateral flow increased to a similar extent in the two groups. In addition, the amount of necrosis associated with a given degree of ischemia was similar in the two groups. Although the extent of the left ventricle that became ischemic was greater in the hypertensive dogs (28 +/- 2 vs. 18 +/- 4%; P < 0.05), chronic hypertension and left ventricular hypertrophy did not limit the recruitment of collateral supply or increase the amount of necrosis associated with a given degree of ischemia.
慢性高血压会增加心肌梗死的风险以及与之相关的发病率和死亡率。尽管加速动脉粥样硬化是部分原因，但与高血压相关的冠状动脉循环中的其他异常，如冠状动脉血管容量降低和毛细血管密度降低，也可能起作用。为了评估这些非动脉粥样硬化异常的影响，我们对9只慢性高血压犬造成了突然的冠状动脉闭塞。高血压犬的平均主动脉压和左心室质量比9只对照犬大约高50%。在闭塞前以及闭塞后5分钟和49小时，用放射性微球测量心肌血流量。此外，对选定心肌节段的梗死范围进行组织学定量分析。我们发现冠状动脉闭塞使两组的血流量降低程度相似，并且在48小时内，两组的侧支血流增加程度相似。此外，两组中与给定程度缺血相关的坏死量相似。尽管高血压犬中发生缺血的左心室范围更大（28±2%对18±4%；P<0.05），但慢性高血压和左心室肥厚并未限制侧支供血的募集，也未增加与给定程度缺血相关的坏死量。
