Frøbert O, Gregersen H, Bjerre J, Bagger J P, Kassab G S
Skejby Hospital, Department of Cardiology, Aarhus University Hospital, DK-8200 Aarhus N, Denmark.
Am J Physiol. 1998 Dec;275(6):H2283-90. doi: 10.1152/ajpheart.1998.275.6.H2283.
The left common coronary arterial trees of eight pig hearts were dissected. The zero-stress state (the state of the organ when the external loads are removed) of the coronary arteries was determined by first cutting the arteries into short, ring-shaped segments perpendicular to the longitudinal axis of the blood vessel and then making a radial cut. This procedure caused the ring to open into a sector whose opening angle (theta), internal and external lengths (circumferences), and wall thickness were measured. Morphometric and theta data were organized in the framework of a diameter-defined Strahler system. We investigated 4 rings from the left common coronary artery (LCCA), 185 from the left anterior descending artery (LAD) and its branches, and 159 from the left circumflex artery (LCX) and its branches. The inner circumferences of the rings ranged over six orders for the LAD arterial tree and five orders for the LCX arterial tree, corresponding to a diameter range of about one order of magnitude for both arteries. theta demonstrates viscoelastic behavior and was measured 30 min after cutting. Our results show that the inner and outer circumference and the wall thickness increase as geometric sequences with the order number. theta is found to decrease linearly toward the smaller orders with a slope of 7.3 degrees/order in the range of the six largest orders. Strain calculations showed that the inner part of the arterial wall is in compression, whereas the outer part of the wall is in tension in the no-load (zero transmural pressure) state. This study provides basic data on the zero-stress state that are necessary for understanding the mechanics of the coronary artery.
对8个猪心脏的左冠状动脉树进行了解剖。通过首先将动脉切成垂直于血管纵轴的短环形段，然后进行径向切割，来确定冠状动脉的零应力状态（去除外部负荷时器官的状态）。此操作使环打开成一个扇形，测量其开口角度（θ）、内外长度（周长）和壁厚。形态测量和θ数据按照直径定义的斯特拉勒系统框架进行整理。我们研究了来自左冠状动脉主干（LCCA）的4个环、来自左前降支动脉（LAD）及其分支的185个环以及来自左旋支动脉（LCX）及其分支的159个环。LAD动脉树中环的内周长范围跨越六个数量级，LCX动脉树中环的内周长范围跨越五个数量级，两条动脉的直径范围约为一个数量级。θ表现出粘弹性行为，在切割后30分钟进行测量。我们的结果表明，内、外周长和壁厚随序号呈几何序列增加。发现在六个最大序号范围内，θ朝着较小序号呈线性下降，斜率为7.3度/序号。应变计算表明，在无负荷（零跨壁压力）状态下，动脉壁的内部受压，而壁的外部受拉。本研究提供了关于零应力状态的基础数据，这对于理解冠状动脉力学是必要的。
