MICROVASCULAR PRESSURES AND RESISTANCES IN THE LEFT-VENTRICULAR SUBEPICARDIUM AND SUBENDOCARDIUM
MICROVASCULAR PRESSURES AND RESISTANCES IN THE LEFT-VENTRICULAR SUBEPICARDIUM AND SUBENDOCARDIUM
复制标题
DOI：
10.1161/01.res.69.3.561
复制
发表时间：
1991-09-01
影响因子：
20.1
通讯作者：
CHILIAN, WM
中科院分区：
文献类型：
--
作者：
CHILIAN, WM
这些实验验证了心外膜下和心内膜下微血管阻力分布的差异可能改变微血管压力的跨壁分布的假设。手术切开分离的血液和生理盐水灌注的猪心脏，以暴露心内膜下和心外膜下微循环。在不同灌注压力下测量心脏骤停和血管最大舒张时的微血管压力，得出不同心内膜下（自由壁和乳头肌）和心外膜下段的灌注压力与微血管压力之间的关系。在相当大小的血管（直径80-120 μ m）中测量两个心肌区域的小动脉和静脉压力。冠状动脉灌注压为100 mm Hg时，心内膜下小动脉和静脉压分别为60 +/- 4和33 +/- 3 mm Hg。相比之下，在相同的冠状动脉灌注压力下，心外膜下微循环的小动脉和静脉压力平均分别为80 +/- 6和22 +/- 3 mm Hg（与心内膜下相比p < 0.05）。在不同冠状动脉灌注压水平下，心内膜下动脉压明显低于心内膜下动脉压（p < 0.05）。除灌注压最低外，心内膜下微循环的静脉压均高于心外膜下微循环（p < 0.05）。心内膜下与心内膜下的动脉、微血管、静脉阻力相对分布也存在差异。具体而言，在心内膜下，动脉和静脉阻力百分比较高，但微血管阻力比例低于心内膜下（p < 0.05）。由此得出结论，心外膜下和心内膜下微循环在最大血管扩张时微血管阻力和压力的分布是不同的。据推测，自身调节能力和缺血易感性的差异可能部分与左心室壁微血管阻力分布不均有关。
These experiments tested the hypothesis that differences in the distribution of subepicardial and subendocardial microvascular resistances may alter the transmural distributions of microvascular pressures. Isolated blood- and physiological saline-perfused porcine hearts were surgically incised to enable exposure of the subendocardial and subepicardial microcirculations. Microvascular pressures were measured during cardiac arrest and maximal vasodilation at various perfusion pressures to formulate relations between perfusion pressure and microvascular pressure in the different subendocardial (both free wall and papillary muscle) and subepicardial segments. Measurements of arteriolar and venular pressures in both myocardial regions were performed in comparably sized vessels (80-120-mu-m in diameter). At a coronary perfusion pressure of 100 mm Hg, subendocardial arteriolar and venular pressures were 60 +/- 4 and 33 +/- 3 mm Hg, respectively. In contrast, at the same coronary perfusion pressure, arteriolar and venular pressures in the subepicardial microcirculation averaged 80 +/- 6 and 22 +/- 3 mm Hg, respectively (p < 0.05 versus subendocardium). At all levels of coronary perfusion pressure, arteriolar pressures were significantly lower in the subendocardium than in the subepicardium (p < 0.05). Venular pressures were also higher in the subendocardial microcirculation than in the subepicardial microcirculation at all but the lowest perfusion pressure (p < 0.05). The relative distribution of resistances in arteries, microvessels, and veins was also different between the subepicardium and subendocardium. Specifically, in the subendocardium, arterial and venous resistances were higher, percentage-wise, but microvascular resistance was proportionately lower than that in the subepicardium (p < 0.05). From these data, it is concluded that the distribution of microvascular resistances and pressures is different during maximal vasodilation in the subepicardial and subendocardial microcirculations of the left ventricle. It is also speculated that differences in autoregulatory capacity and vulnerability to ischemia may be partially related to unequal distribution of microvascular resistances across the wall of the left ventricle.