Goubergrits L, Mevert R, Yevtushenko P, Schaller J, Kertzscher U, Meier S, Schubert S, Riesenkampff E, Kuehne T
Biofluid Mechanics Laboratory, Charité-Universitätsmedizin Berlin, Thielallee 73, 14195, Berlin, Germany,
Ann Biomed Eng. 2013 Dec;41(12):2575-87. doi: 10.1007/s10439-013-0879-2. Epub 2013 Aug 2.
Aortic coarctation (CoA) accounting for 3-11% of congenital heart disease can be successfully treated. Long-term results, however, have revealed decreased life expectancy associated with abnormal hemodynamics. Accordingly, an assessment of hemodynamics is the key factor in treatment decisions and successful long-term results. In this study, 3D angiography whole heart (3DWH) and 4D phase-contrast magnetic resonance imaging (MRI) data were acquired. Geometries of the thoracic aorta with CoAs were reconstructed using ZIB-Amira software. X-ray angiograms were used to evaluate the post-treatment geometry. Computational fluid dynamics models in three patients were created to simulate pre- and post-treatment situations using the FLUENT program. The aim of the study was to investigate the impact of the inlet velocity profile (plug vs. MRI-based) with a focus on the peak systole pressure gradient and wall shear stress (WSS). Results show that helical flow at the aorta inlet can significantly affect the assessment of pressure drop and WSS. Simplified plug inlet velocity profiles significantly (p < 0.05) overestimate the pressure drop in pre- and post-treatment geometries and significantly (p < 0.05) underestimate surface-averaged WSS. We conclude that the use of the physiologically correct but time-expensive 4D MRI-based in vivo velocity profile in CFD studies may be an important step towards a patient-specific analysis of CoA hemodynamics.
主动脉缩窄（CoA）占先天性心脏病的3%-11%，可得到成功治疗。然而，长期结果显示，与异常血流动力学相关的预期寿命缩短。因此，血流动力学评估是治疗决策和长期成功结果的关键因素。在本研究中，采集了三维血管造影全心脏（3DWH）和四维相位对比磁共振成像（MRI）数据。使用ZIB-Amira软件重建了患有CoA的胸主动脉几何形状。利用X射线血管造影评估治疗后的几何形状。使用FLUENT程序创建了三名患者的计算流体动力学模型，以模拟治疗前和治疗后的情况。本研究的目的是研究入口速度剖面（栓塞型与基于MRI型）的影响，重点关注收缩期峰值压力梯度和壁面剪应力（WSS）。结果表明，主动脉入口处的螺旋流可显著影响压降和WSS的评估。简化的栓塞型入口速度剖面显著（p<0.05）高估了治疗前和治疗后几何形状中的压降，且显著（p<0.05）低估了表面平均WSS。我们得出结论，在CFD研究中使用生理上正确但耗时的基于四维MRI的体内速度剖面，可能是朝着CoA血流动力学的患者特异性分析迈出的重要一步。
