Huo Yunlong, Linares Carlos O, Kassab Ghassan S
Department of Biomedical Engineering, Surgery and Cellular and Integrative Physiology, Indiana University-Purdue University Indianapolis, IN 46202, USA.
Circ Res. 2007 Feb 2;100(2):273-83. doi: 10.1161/01.RES.0000257777.83431.13. Epub 2007 Jan 11.
It has been shown that right ventricle (RV) hypertrophy involves significant compensatory vascular growth and remodeling. The objective of the present study was to determine the functional implications of the vascular growth and remodeling through a full flow analysis of arterial tree down to first capillary segments. A computer reconstruction of RV branches including the proximal right coronary artery to the posterior descending artery was established based on measured morphometric data in arrested, vasodilated porcine heart. The flows were computed throughout the reconstructed trees based on conservation of mass and momentum and appropriate pressure boundary conditions. It was found that the flow rate was significantly increased in large epicardial coronary arteries in hypertrophic as compared with control hearts but normalized in the intramyocardial coronary arteries and smaller vessels in RV hypertrophy primarily because of the significant increase in number of arterioles. Furthermore, the wall shear stress was restored to nearly homeostatic levels throughout most of the vasculature after 5 weeks of RV hypertrophy. The compensatory remodeling in RV hypertrophy functionally restores the perfusion at the arteriolar and capillary level and wall shear stress in most of larger vessels. This is the first full analysis of coronary arterial tree, with millions of vessels, in cardiac hypertrophy that reveals the compensatory adaptation of structure to function.
研究表明，右心室（RV）肥大涉及显著的代偿性血管生长和重塑。本研究的目的是通过对直至第一级毛细血管段的动脉树进行全血流分析，来确定血管生长和重塑的功能意义。基于在停搏、血管扩张的猪心脏中测量的形态学数据，建立了包括从右冠状动脉近端到后降支动脉的右心室分支的计算机重建模型。基于质量和动量守恒以及适当的压力边界条件，计算了整个重建树中的血流。结果发现，与对照心脏相比，肥大心脏的心外膜大冠状动脉中的血流速度显著增加，但右心室肥大时心肌内冠状动脉和较小血管中的血流速度恢复正常，这主要是由于小动脉数量显著增加。此外，右心室肥大5周后，大部分血管系统中的壁面剪应力恢复到接近稳态水平。右心室肥大中的代偿性重塑在功能上恢复了小动脉和毛细血管水平的灌注以及大多数较大血管中的壁面剪应力。这是首次对心脏肥大中包含数百万血管的冠状动脉树进行全面分析，揭示了结构对功能的代偿性适应。
