Research and Development Unit, National Heart Centre Singapore, 17 third hospital avenue, Mistri Wing, Singapore 168752, Singapore.
Department of Mechanics and Engineering Science, College of Engineering, Peking University, Mechanics Building 507, Beijing 10087, China.
Comput Biol Med. 2014 Apr;47:130-8. doi: 10.1016/j.compbiomed.2014.01.001. Epub 2014 Feb 11.
Coronary heart disease causes obstruction of coronary blood flow and is the leading cause of death worldwide. The effect of focal stenosis on downstream flow pattern in the coronary arterial tree is not well understood. Here, the blood flows in normal and diseased porcine left anterior descending (LAD) arterial tree were modeled and compared to determine the effects of stenosis on the blood flow distribution and hemodynamic parameters. The anatomical model of LAD was extracted from a porcine heart by computed tomography (CT), which was comprised of a main trunk and nine side branches. Stenoses with various severities were imposed into the main trunk between the first and second side branches, and the boundary condition at each outlet accounted for the effect of stenosis on the flow rate in the downstream vasculature. It was found that only significant stenosis (≥75% area reduction) considerably altered pressure drop and total flow rate distribution in branches and at each bifurcation. The effect of significant stenosis on bifurcations, however, diminished at downstream locations. As demonstrated by distributions of oscillatory shear index and relative residence time, non-significant stenosis (<75% area reduction) has the potential to induce atherosclerosis near the ostium of downstream side branch, while significant stenosis can promote atherosclerosis in its wake.
冠心病导致冠状动脉血流阻塞，是全球范围内主要的致死原因。人们对于局灶性狭窄对冠状动脉树下游血流模式的影响还了解甚少。在此，我们对正常和患病猪的左前降支（LAD）动脉树中的血流进行建模和比较，以确定狭窄对血流分布和血流动力学参数的影响。LAD 的解剖模型通过计算机断层扫描（CT）从猪心提取，该模型由一个主干和九个侧支组成。在第一和第二个侧支之间的主干上施加了各种严重程度的狭窄，每个出口的边界条件考虑了狭窄对下游血管中血流速率的影响。结果发现，只有严重狭窄（≥75%面积减少）才会显著改变分支和每个分叉处的压降和总流量分布。然而，在下游位置，严重狭窄对分叉的影响会减小。如振荡剪切指数和相对停留时间的分布所示，非严重狭窄（<75%面积减少）有可能在下游侧支的口部附近引发动脉粥样硬化，而严重狭窄则可能在其后促进动脉粥样硬化的发生。
