Zhu Yu, Xu Xiao Yun, Mason Justin, Mirsadraee Saeed
Department of Chemical Engineering, Imperial College London, London, UK.
Rheumatology and Vascular Science, Hammersmith Hospital, Imperial College London, London, UK.
JVS Vasc Sci. 2023 Aug 24;4:100125. doi: 10.1016/j.jvssci.2023.100125. eCollection 2023.
Takayasu arteritis (TA) is a difficult disease to deal with because there are neither reliable clinical signs, laboratory biomarkers, nor a single noninvasive imaging technique that can be used for early diagnosis and disease activity monitoring. Knowledge of aortic hemodynamics in TA is lacking. This study aimed to fill this gap by assessing hemodynamics in patients with TA using image-based computational fluid dynamics (CFD) simulations.
Eleven patients with TA were included in the present study. Patient-specific geometries were reconstructed from either clinical aortic computed tomography angiography or magnetic resonance angiography studies and coupled with physiological boundary conditions for CFD simulations. Key anatomical and hemodynamic parameters were compared with a control group consisting of 18 age- and sex-matched adults without TA who had healthy aortas.
Compared with controls, patients with TA had significantly higher aortic velocities (0.9 m/s [0.7, 1.1 m/s] vs 0.6 m/s [0.5, 0.7 m/s]; = .002), maximum time-averaged wall shear stress (14.2 Pa [9.8, 20.9 Pa] vs 8.0 Pa [6.2, 10.3 Pa]; = .004), and maximum pressure drops between the ascending and descending aorta (36.9 mm Hg [29.0, 49.3 mm Hg] vs 28.5 mm Hg [25.8, 31.5 mm Hg]; = .004). These significant hemodynamic alterations in patients with TA might result from abnormal anatomical features including smaller arch diameter (20.0 mm [13.8, 23.3 mm] vs 25.2 mm [23.3, 26.8 mm]; = .003), supra-aortic branch diameters (21.9 mm [18.5, 24.6 mm] vs 25.7 mm [24.3, 28.3 mm]; = .003) and descending aorta diameter (14.7 mm [12.2, 16.8 mm] vs 22.5 mm [19.8, 24.0 mm]; < .001).
CFD analysis reveals hemodynamic changes in the aorta of patients with TA. The applicability of CFD technique coupled with standard imaging assessments in predicting disease progression of such patients will be explored in future studies. Future large cohort study with outcome correlation is also warranted.
Based on patient-specific computational fluid dynamics simulations, the present retrospective study revealed significant difference in aortic hemodynamics between the patients with and without Takayasu arteritis (TA). To the best of our knowledge, this study is the first to evaluate hemodynamic conditions within TA, demonstrating the potential of computational flow modeling in capturing abnormal hemodynamic forces, such as high wall shear stress, resulted from irregular morphological changes. In the future, assessing the hemodynamic parameters within patients with TA during the prestenotic period, together with longitudinal computational fluid dynamics studies may allow better monitoring and management of TA.
高安动脉炎（TA）是一种难以应对的疾病，因为既没有可靠的临床体征、实验室生物标志物，也没有单一的非侵入性成像技术可用于早期诊断和疾病活动监测。目前缺乏关于TA患者主动脉血流动力学的认识。本研究旨在通过基于图像的计算流体动力学（CFD）模拟评估TA患者的血流动力学，以填补这一空白。
本研究纳入了11例TA患者。根据临床主动脉计算机断层血管造影或磁共振血管造影研究重建患者特异性几何模型，并结合生理边界条件进行CFD模拟。将关键的解剖学和血流动力学参数与由18名年龄和性别匹配、无TA且主动脉健康的成年人组成的对照组进行比较。
与对照组相比，TA患者的主动脉速度显著更高（0.9 m/s [0.7, 1.1 m/s] 对 0.6 m/s [0.5, 0.7 m/s]；P = 0.002），最大时间平均壁面剪应力显著更高（14.2 Pa [9.8, 20.9 Pa] 对 8.0 Pa [6.2, 10.3 Pa]；P = 0.004），升主动脉和降主动脉之间的最大压力降显著更高（36.9 mmHg [29.0, 49.3 mmHg] 对 28.5 mmHg [25.8, 31.5 mmHg]；P = 0.004）。TA患者这些显著的血流动力学改变可能是由异常的解剖特征导致的，包括较小的主动脉弓直径（20.0 mm [13.8, 23.3 mm] 对 25.2 mm [23.3, 26.8 mm]；P = 0.003）、主动脉弓上分支直径（21.9 mm [18.5, 24.6 mm] 对 25.7 mm [24.3, 28.3 mm]；P = 0.003）和降主动脉直径（14.7 mm [12.2, 16.8 mm] 对 22.5 mm [19.8, 24.0 mm]；P < 0.001）。
CFD分析揭示了TA患者主动脉的血流动力学变化。未来的研究将探索CFD技术与标准成像评估相结合在预测此类患者疾病进展中的适用性。未来还需要进行有结果相关性的大型队列研究。
基于患者特异性计算流体动力学模拟，本回顾性研究揭示了有和没有高安动脉炎（TA）患者之间主动脉血流动力学的显著差异。据我们所知，本研究是首次评估TA患者的血流动力学状况，证明了计算流体动力学建模在捕捉由不规则形态变化导致的异常血流动力学力（如高壁面剪应力）方面的潜力。未来，在狭窄前期评估TA患者的血流动力学参数，以及进行纵向计算流体动力学研究，可能有助于更好地监测和管理TA。
