Background Computational fluid dynamics (CFD) simulations model blood flow in aortic pathologies. The aim of our study was to understand the local hemodynamic environment at the site of rupture in distal stent graft–induced new entry (dSINE) after frozen elephant trunk with a clinically time efficient steady-flow simulation versus transient simulations.

Methods Steady-state simulations were performed for dSINE, prior and after its development and prior to aortic rupture. To account for potential turbulences due geometric changes at the dSINE location, Reynolds-averaged Navier–Stokes equations with the realizable k-ε model for turbulences were applied. Transient simulations were performed for comparison. Hemodynamic parameters were assessed at various locations of the aorta.

Results Post-dSINE, jet-like flow due to luminal narrowing was observed which increased prior to rupture and resulted in focal neighbored regions of high and low wall shear stress (WSS). Prior to rupture, aortic diameter at the rupture site increased lowering WSS at the entire aortic circumference. Concurrently, WSS and turbulence increased locally above the entry tear at the inner aortic curvature. Turbulent kinetic energy and WSS elevation in the downstream aorta demonstrated enhanced stress on the native aorta. Results of steady-state simulations were in good qualitative agreement with transient simulations.

Conclusion Steady-flow CFD simulations feasible at clinical time scales prior to aortic rupture reveal a hostile hemodynamic environment at the dSINE rupture site in agreement with lengthy transient simulations. Consequently, our developed approach may be of value in treatment planning where a fast assessment of the local hemodynamic environment is essential.

背景 计算流体动力学 (CFD) 模拟可模拟主动脉病变中的血流。我们研究的目的是通过临床时间高效的稳定流模拟与瞬态模拟来了解冷冻象鼻后远端支架移植物诱导新进入 (dSINE) 破裂部位的局部血流动力学环境。

方法 在 dSINE 开发之前和之后以及主动脉破裂之前进行稳态模拟。为了解释 dSINE 位置几何变化引起的潜在湍流，应用了具有可实现k -ε 湍流模型的雷诺平均纳维-斯托克斯方程。进行瞬态模拟以进行比较。在主动脉的不同位置评估血流动力学参数。

结果 dSINE 后，观察到由于管腔变窄而导致的喷射状流动，该流动在破裂之前增加，并导致高和低壁剪切应力 (WSS) 的局部相邻区域。破裂前，破裂部位的主动脉直径增加，整个主动脉周围的 WSS 降低。同时，主动脉内曲率入口撕裂上方的 WSS 和湍流局部增加。下游主动脉的湍流动能和 WSS 升高表明对原生主动脉的压力增强。稳态模拟的结果与瞬态模拟具有良好的定性一致性。

结论 在主动脉破裂前的临床时间尺度上，稳流 CFD 模拟是可行的，揭示了 dSINE 破裂部位的不良血流动力学环境，与长时间的瞬态模拟一致。因此，我们开发的方法可能在治疗计划中有价值，其中快速评估局部血流动力学环境至关重要。