Left Ventricular Trabeculations Decrease the Wall Shear Stress and Increase the Intra-Ventricular Pressure Drop in CFD Simulations
Left Ventricular Trabeculations Decrease the Wall Shear Stress and Increase the Intra-Ventricular Pressure Drop in CFD Simulations
复制标题
CFD 模拟中左心室小梁可降低壁剪应力并增加心室内压降
作者：
F. Sacco;B. Paun;O. Lehmkuhl;T. Iles;P. Iaizzo;G. Houzeaux;M. Vázquez;C. Butakoff;J. Aguado
本研究的目的是描述左心室（LV）几何形状的血流动力学特征，以使用高性能计算（HPC）检查小梁和乳头肌（PM）对血流的影响。五对详细的和平滑的左心室内膜模型重建的高分辨率磁共振图像（MRI）的离体人类心脏。一对左心室的详细模型仅由PM和少量大小梁表征，以代表最新水平的内镜细节。获得的其他四个详细模型包括横截面积≥1 mm 2的内分泌结构。几何特征是使用计算流体动力学（CFD）模拟与刚性壁和恒定和瞬态流输入的详细和平滑的模型进行比较。这些模拟不代表临床或生理情况，而是表征内支架结构与血流的相互作用。采用定常流模拟来量化LV的入口和出口之间的压降和壁面剪切应力（WSS）。相干结构进行了分析，使用Q-标准的恒定和瞬态流输入。我们的研究结果表明，小梁和PM增加心室内的压力下降，减少WSS和破坏占主导地位的单涡，通常存在于平滑的endocompatibility模型，产生二次小涡。考虑到获得高分辨率解剖细节在体内具有挑战性，我们建议通过沿LV内膜壁沿着添加多孔层，将小梁的影响纳入平滑的心室几何形状。结果表明，在光滑的心室模型上，厚度为1.2·10−2 m、孔隙率为20 kg/m2的多孔层近似于在详细模型中观察到的压降、涡度和WSS。
The aim of the present study is to characterize the hemodynamics of left ventricular (LV) geometries to examine the impact of trabeculae and papillary muscles (PMs) on blood flow using high performance computing (HPC). Five pairs of detailed and smoothed LV endocardium models were reconstructed from high-resolution magnetic resonance images (MRI) of ex-vivo human hearts. The detailed model of one LV pair is characterized only by the PMs and few big trabeculae, to represent state of art level of endocardial detail. The other four detailed models obtained include instead endocardial structures measuring ≥1 mm2 in cross-sectional area. The geometrical characterizations were done using computational fluid dynamics (CFD) simulations with rigid walls and both constant and transient flow inputs on the detailed and smoothed models for comparison. These simulations do not represent a clinical or physiological scenario, but a characterization of the interaction of endocardial structures with blood flow. Steady flow simulations were employed to quantify the pressure drop between the inlet and the outlet of the LVs and the wall shear stress (WSS). Coherent structures were analyzed using the Q-criterion for both constant and transient flow inputs. Our results show that trabeculae and PMs increase the intra-ventricular pressure drop, reduce the WSS and disrupt the dominant single vortex, usually present in the smoothed-endocardium models, generating secondary small vortices. Given that obtaining high resolution anatomical detail is challenging in-vivo, we propose that the effect of trabeculations can be incorporated into smoothed ventricular geometries by adding a porous layer along the LV endocardial wall. Results show that a porous layer of a thickness of 1.2·10−2 m with a porosity of 20 kg/m2 on the smoothed-endocardium ventricle models approximates the pressure drops, vorticities and WSS observed in the detailed models.
影响因子：
20.1
作者：
Trayanova NA
通讯作者：
Trayanova NA