Fig 5 from Computational tools for clinical support: a multi-scale compliant model for haemodynamic simulations in an aortic dissection based on multi-modal imaging data

Aortic dissection (AD) is a vascular condition with high morbidity and mortality rates. Computational fluid dynamics (CFD) can provide insight into the progression of AD and aid clinical decisions; however, oversimplified modelling assumptions and high computational cost compromise the accuracy of the information and impede clinical translation. To overcome these limitations, a patient-specific CFD multi-scale approach coupled to Windkessel boundary conditions and accounting for wall compliance was developed and used to study an AD patient. A new moving boundary algorithm was implemented to capture wall displacement and a rich <i>in vivo</i> clinical dataset was used to tune model parameters and for validation. Comparisons between <i>in silico</i> and <i>in vivo</i> data showed that this approach successfully captures flow and pressure waves for the patient-specific AD and is able to predict the pressure in the false lumen (FL), a critical variable for the clinical management of the condition. Results showed regions of low and oscillatory wall shear stress which, together with higher diastolic pressures predicted in the FL, may indicate risk of expansion. This study, at the interface of engineering and medicine, demonstrates a relatively simple and computationally efficient approach to account for arterial deformation and wave propagation phenomena in a three-dimensional model of AD, representing a step forward in the use of CFD as potential tool for AD management and clinical support.

主动脉夹层（Aortic dissection, AD）是一种发病率与死亡率均较高的血管疾病。计算流体动力学（Computational fluid dynamics, CFD）可助力阐明AD的疾病进展并辅助临床决策，但过度简化的建模假设与高昂的计算成本会损害分析结果的准确性，阻碍其临床转化。为克服上述局限，本研究开发了一种耦合Windkessel边界条件且考虑血管壁顺应性的患者特异性CFD多尺度方法，并将其应用于一例AD患者的研究。本研究实现了一种新型移动边界算法以捕捉血管壁位移，并采用丰富的体内（in vivo）临床数据集对模型参数进行校准与验证。计算机模拟（in silico）数据与体内临床数据的对比结果表明，该方法可成功捕捉患者特异性AD的血流与压力波，并能够预测假腔（false lumen, FL）内的压力——该指标是AD临床管理的关键变量。研究结果显示存在低剪切应力与振荡壁面切应力区域，结合假腔中预测的更高舒张压，或可提示血管扩张风险。本研究作为工程学与医学的交叉成果，提出了一种相对简便且计算高效的方法，可在AD的三维模型中纳入动脉变形与波传播现象，为将CFD作为AD管理与临床支持的潜在工具迈出了重要一步。