Department of Cardiothoracic Surgery, Stanford University School of Medicine, California.
Department of Cardiothoracic Surgery, Stanford University School of Medicine, California.
Semin Thorac Cardiovasc Surg. 2022 Summer;34(2):443-448. doi: 10.1053/j.semtcvs.2021.05.012. Epub 2021 Jun 3.
We aim to use computational fluid dynamics to investigate the hemodynamic conditions that may predispose to false lumen enlargement in this patient population. Nine patients who received surgical repairs of their type-A aortic dissections between 2017-2018 were retrospectively identified. Multiple contrast-enhanced post-operative CT scans were used to construct 3D models of aortic geometries. Computational fluid dynamics simulations of the models were run on a high-performance computing cluster using SimVascular - an open-source simulation package. Physiological pulsatile flow conditions (4.9 L/min) were used at the aortic true lumen inlet, and physiological vascular resistances were applied at the distal vascular ends. Exploratory analyses showed no correlation between rate of false lumen growth and blood pressure, immediate post-op aortic diameter, or the number of fenestrations (p = 0.2). 1-year post-operative CT scans showed a median false lumen growth rate of 4.31 (3.66, 14.67) mm/year Median (Interquartile range) peak systolic, mid-diastolic, and late diastolic velocity magnitudes were 0.90 (1.40); 0.10 (0.16); and 0.06 (0.06) cm/s respectively. Spearman's ranked correlations between fenestration velocity and 1-year false lumen growth rates were found to be statistically significant: Velocity magnitude at peak systolic (p = 0.025; rho = 0.75), mid diastolic (p = 0.025; rho = 0.75) and late diastolic phases of the cardiac cycle (p = 0.006; rho = 0.85). We have shown that false lumen growth is strongly correlated to fenestration flow velocity, which has potential implications for post-operative surveillance and risk stratification.
我们旨在使用计算流体动力学来研究可能导致此类患者假腔扩大的血流动力学条件。回顾性地确定了 9 例在 2017-2018 年间接受主动脉夹层 A 型手术修复的患者。使用多个对比增强术后 CT 扫描构建主动脉几何形状的 3D 模型。使用 SimVascular（一个开源模拟软件包）在高性能计算集群上运行模型的计算流体动力学模拟。在主动脉真腔入口处使用生理脉动流条件（4.9 L/min），并在远端血管末端施加生理血管阻力。探索性分析表明，假腔生长率与血压、术后即刻主动脉直径或窗孔数量之间无相关性（p=0.2）。1 年术后 CT 扫描显示假腔生长率中位数为 4.31（3.66，14.67）mm/年中位数（四分位间距）最大收缩期、中期舒张期和晚期舒张期速度幅度分别为 0.90（1.40）、0.10（0.16）和 0.06（0.06）cm/s。窗孔速度与 1 年假腔生长率之间的斯皮尔曼等级相关分析显示具有统计学意义：峰值收缩期（p=0.025；rho=0.75）、中期舒张期（p=0.025；rho=0.75）和晚期舒张期心动周期（p=0.006；rho=0.85）的速度幅度。我们已经表明，假腔生长与窗孔血流速度密切相关，这对术后监测和风险分层具有潜在意义。
