Kassab G S, Imoto K, White F C, Rider C A, Fung Y C, Bloor C M
Department of Applied Mechanics and Engineering Sciences/Bioengineering, University of California, San Diego, La Jolla 92093-0412.
Am J Physiol. 1993 Jul;265(1 Pt 2):H366-75. doi: 10.1152/ajpheart.1993.265.1.H366.
We investigated coronary vascular adaptations occurring in right ventricular hypertrophy (RVH). Six pigs had RVH induced by pulmonary artery stenosis for 5 wk. Three pigs served as controls. At autopsy we made silicone elastomer casts of the right coronary arteries (RCA) and collected morphometric data. We organized the segments and their diameters and lengths into a framework of a modified Strahler's ordering scheme in which the order number of an offspring is increased only if its diameter is greater than the diameters of its parents by a specific amount. The segments of the same order arranged in series are combined into elements. In RVH the total number of orders of vessels was larger than the control by 1; the total number of elements in each order increased greatly, whereas the diameters and lengths of each order decreased somewhat. The total RCA resistance decreased in RVH mainly because the total cross-sectional area (CSA) of every order was increased. Because the diameters of the resistance vessels decreased, this decrease in total RCA resistance was due to a numerical increase in resistance vessels. These findings indicate that new flow channels have been established. In contrast, the RCA was remodeled in that the lumen diameter increased. Pressure-flow curves showed a decrease of coronary resistance in RVH, in agreement with the morphometric findings. We conclude that there is significant remodeling of the coronary arterial vasculature in RVH, and any future analysis of coronary hemodynamics of the right ventricle in hypertrophy must take the morphometric remodeling into account.
我们研究了右心室肥大（RVH）时发生的冠状动脉血管适应性变化。六只猪通过肺动脉狭窄诱导RVH持续5周。三只猪作为对照。尸检时，我们制作了右冠状动脉（RCA）的硅橡胶弹性体铸型并收集了形态计量学数据。我们将这些节段及其直径和长度整理成一个改良的斯特勒分级方案框架，其中只有当一个分支的直径比其亲本的直径大特定量时，其分级数才会增加。串联排列的相同级别的节段合并为单元。在RVH中，血管的总级数比对照组多1级；各级单元总数大幅增加，而各级的直径和长度有所减小。RVH中RCA总阻力降低主要是因为各级的总横截面积（CSA）增加。由于阻力血管直径减小，RCA总阻力的降低是由于阻力血管数量增加。这些发现表明已建立了新的血流通道。相比之下，RCA发生了重塑，管腔直径增大。压力-流量曲线显示RVH中冠状动脉阻力降低，与形态计量学结果一致。我们得出结论，RVH中冠状动脉血管存在显著重塑，未来对肥厚右心室冠状动脉血流动力学的任何分析都必须考虑形态计量学重塑。
