The Role of Autoregulation and Tissue Diastolic Pressures in the Transmural Distribution of Left Ventricular Blood Flow in Anesthetized Dogs
The Role of Autoregulation and Tissue Diastolic Pressures in the Transmural Distribution of Left Ventricular Blood Flow in Anesthetized Dogs
复制标题
自动调节和组织舒张压在麻醉犬左心室血流跨壁分布中的作用
作者：
J. Rouleau;L. Boerboom;J. Hoffman
为了研究自动调节如何影响跨壁心肌血流量，我们研究了21只开胸犬，其冠状动脉压独立于左心室压而变化。在冠状动脉自动调节或最大扩张冠状动脉时注入直径为9/AN的微球，测量左室心肌总血流量(FLV)和心内膜下心外膜下血流量比(I：O)。在自动调节的情况下，在稳定状态下，随着左心室+功的恒定，在很大范围内改变冠脉灌流压，导致冠脉流量恒定；流量在这一范围以下减少，在此范围以上增加。当冠状动脉流量从自动调节流量升高或降低时，冠状动脉压力分别升高或下降，以达到当冠状动脉压力故意变化时所确定的压力-流量曲线上的值。在自主调节心脏中，当冠脉压力发生变化时，在0.45~1.0范围内，FLV和1：0比值与舒张期冠脉压力时间指数(DPTU)和左心室收缩压时间指数(SPTI)的比值无关，但I：O在压力比小于0.45时下降，当压比大于1时增大。在血管扩张过程中，FLV和I/O比值随DPTL：SPT1呈线性变化。因此，冠脉自动调节对于维持广泛的冠脉-室压关系中的FLV和I：O分布是必要的。随着最大的血管扩张，低冠状动脉压下的血流从心内膜下层增加到心外膜下层，从而提示舒张期组织压力的梯度。矿石资源45：804-815,1979
To investigate how autoregulation affects transmural myocardial blood flow, we studied 21 open-chest dogs and varied coronary arterial pressure independently of left ventricular pressure. Total left ventricular myocardial blood flow (FLV) and subendocardiaksubepicardial blood flow ratio (I:O) were measured with microspheres, 9 /an in diameter, injected during autoregulation or maximal coronary vasodilation. With autoregulation, changing coronary perfusing pressures over a wide range with constant left ventricular +work at steady state resulted in constant coronary flow; flows decreased below and increased above this range. When coronary flow was raised or lowered from the autoregulated flow, coronary pressures rose or fell, respectively, to reach values on the pressure-flow curve determined when coronary pressures were varied deliberately. When coronary pressure was changed in autoregulating hearts, FLv and 1:0 ratios were independent of the ratio of diastolic coronary pressure time index (DPTU) to left ventricular systolic pressure time index (SPTI) over the range, 0.45-1.0, but I:O fell with pressure ratios below 0.45 and increased with pressure ratios above one. During vasodilation, FLV and I:O ratios varied linearly with DPTL:SPT1. Thus, coronary autoregulation is necessary to maintain FLV and I:O distribution over a wide range of coronary:ventricular pressure relationships. With maximal vasodilation, flow at low coronary pressures increased from subendocardial to subepicardial layers, thereby suggesting a gradient of diastolic tissue pressures. Ore Res 45: 804-815, 1979