A patient-specific study of type-B aortic dissection: evaluation of true-false lumen blood exchange.
A patient-specific study of type-B aortic dissection: evaluation of true-false lumen blood exchange.
复制标题
B 型主动脉夹层患者特异性研究：真假腔血液交换的评估
DOI：
10.1186/1475-925x-12-65
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发表时间：
2013-07-06
影响因子：
3.9
通讯作者：
Ventikos Y
中科院分区：
文献类型：
--
作者：
Chen D;Müller-Eschner M;von Tengg-Kobligk H;Barber D;Böckler D;Hose R;Ventikos Y
主动脉夹层是一种严重的病理状态，其中血液渗透到主动脉壁的层之间并创建复制通道-假腔。主动脉形态的这种显著变化显著改变了血流动力学特征，在破裂的情况下，引起明显高的发病率和死亡率。在这项研究中，我们建立了一个特定的计算模型和模拟的脉动血流夹层主动脉内。湍流模型采用k-ω SST湍流模型，数值求解采用有限体积法。我们的重点是在心动周期中真腔和假腔之间的流量交换，并对特定通道的流量进行量化。载荷分布，包括压力和壁面剪应力也进行了研究，并采用适当的湍流模型的解决方案，直接模拟的结果进行了比较。我们的研究结果表明：（i）高流速发生在入口的周边;（ii）对于所研究的病例，在心跳周期中约有40%的血流通过假腔;（iii）在夹层外壁发现较高的压力，这可能会引起假腔的进一步扩张;（iv）最高的壁面剪应力出现在入口周围，这可能表明该区域易于进一步分裂;和（v）层流模拟具有足够精细的网格分辨率，特别是在壁面附近的精细网格分辨率，可以捕获与（粗网格）湍流结果，尽管计算的绝对量级一般较小。主动脉夹层的患者特异性模型提供了真腔和假腔内血液运输的详细流动信息，并量化了主动脉和夹层壁上的载荷分布。这有助于评价假腔中潜在的血栓形成行为，并且在指导血管内介入中至关重要。此外，作为一个计算研究，网格要求，成功地评估血液动力学参数已被提出。
Aortic dissection is a severe pathological condition in which blood penetrates between layers of the aortic wall and creates a duplicate channel – the false lumen. This considerable change on the aortic morphology alters hemodynamic features dramatically and, in the case of rupture, induces markedly high rates of morbidity and mortality. In this study, we establish a patient-specific computational model and simulate the pulsatile blood flow within the dissected aorta. The k-ω SST turbulence model is employed to represent the flow and finite volume method is applied for numerical solutions. Our emphasis is on flow exchange between true and false lumen during the cardiac cycle and on quantifying the flow across specific passages. Loading distributions including pressure and wall shear stress have also been investigated and results of direct simulations are compared with solutions employing appropriate turbulence models. Our results indicate that (i) high velocities occur at the periphery of the entries; (ii) for the case studied, approximately 40% of the blood flow passes the false lumen during a heartbeat cycle; (iii) higher pressures are found at the outer wall of the dissection, which may induce further dilation of the pseudo-lumen; (iv) highest wall shear stresses occur around the entries, perhaps indicating the vulnerability of this region to further splitting; and (v) laminar simulations with adequately fine mesh resolutions, especially refined near the walls, can capture similar flow patterns to the (coarser mesh) turbulent results, although the absolute magnitudes computed are in general smaller. The patient-specific model of aortic dissection provides detailed flow information of blood transport within the true and false lumen and quantifies the loading distributions over the aorta and dissection walls. This contributes to evaluating potential thrombotic behavior in the false lumen and is pivotal in guiding endovascular intervention. Moreover, as a computational study, mesh requirements to successfully evaluate the hemodynamic parameters have been proposed.