The coronary artery hemodynamics are impacted by both the macrocirculation and microcirculation. Whether microcirculation load impact the functional assessment of a coronary artery stenosis is unknown. The purpose of this study is to investigate the effect of porous media of the microcirculation on fractional flow reserve (FFR) in stenotic coronary artery model. A three dimensional computational simulation of blood flow in coronary artery symmetric stenotic model was constructed. The computational fluid dynamics (CFD) model was developed with Fluent 16.0. Blood was modeled as a shear thinning, non-Newtonian fluid with the Carreau model. A seepage outlet boundary condition and transient inlet conditions were imposed on the model. Coronary physiologica diagnostic parameter such as pressure, velocity and fractional flow reserve (FFR) were investigated in the model and compared with the microcirculation load (ML) and constant pressure load (PL) condition. The present study showed the different hemodynamics in the ML and PL condition. The pre-stenotic pressure is almost the same in the two model. However the pressure in the post-stenotic artery domain is much lower in the PL model. The fluctuation range of the pressures is much higher in ML model than those in PL model. The velocity flow was more steady and lower in the ML model. For the PL model with 75% artery stenosis the FFR was 0.776, while for the ML model with the same stenosis, the FFR was 0.813. This study provides evidence that FFR increased in the presentation of ML condition. There is a strong hemodynamic effect of microcirculation on coronary artery stenosis.

中文翻译：

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微循环负荷对冠状动脉狭窄模型中FFR的影响

冠状动脉的血流动力学受大循环和微循环的影响。微循环负荷是否影响冠状动脉狭窄的功能评估尚不清楚。这项研究的目的是研究狭窄的冠状动脉模型中微循环的多孔介质对分数血流储备（FFR）的影响。建立了冠状动脉对称性狭窄模型血流的三维计算仿真。Fluent 16.0开发了计算流体动力学（CFD）模型。用Carreau模型将血液建模为剪切稀化的非牛顿流体。在模型上施加了渗流出口边界条件和瞬态入口条件。冠脉生理诊断参数，例如压力，在模型中研究了流速和分流储备（FFR），并与微循环负荷（ML）和恒压负荷（PL）条件进行了比较。本研究显示了ML和PL条件下的不同血流动力学。在两个模型中，狭窄前的压力几乎相同。但是，在PL模型中，狭窄后动脉区域的压力要低得多。ML模型中的压力波动范围远大于PL模型中的波动范围。在ML模型中，速度流更稳定且更低。对于具有75％动脉狭窄的PL模型，FFR为0.776，而对于具有相同狭窄的ML模型，FFR为0.813。这项研究提供了证据，表明ML病状的FFR增加。微循环对冠状动脉狭窄有很强的血液动力学作用。