Institute of Turbomachinery, University of Rostock, Rostock, Germany.
Int J Artif Organs. 2024 Aug;47(8):624-632. doi: 10.1177/03913988241268067. Epub 2024 Sep 5.
Medical advancements, particularly in ventricular assist devices (VADs), have notably advanced heart failure (HF) treatment, improving patient outcomes. However, challenges such as adverse events (strokes, bleeding and thrombosis) persist. Computational fluid dynamics (CFD) simulations are instrumental in understanding VAD flow dynamics and the associated flow-induced adverse events resulting from non-physiological flow conditions in the VAD.This study aims to validate critical CFD simulation parameters for accurate VAD simulations interacting with the cardiovascular system, building upon the groundwork laid by Hahne et al. A bidirectional coupling technique was used to model dynamic (pulsatile) flow conditions of the VAD CFD interacting with the cardiovascular system. Mesh size, time steps and simulation method (URANS, LES) were systematically varied to evaluate their impact on the dynamic pump performance (dynamic curve) of the HeartMate 3, aiming to find the optimal simulation configuration for accurately reproduce the dynamic curve. The new Overlapping Ratio (OR) method was developed and applied to quantify dynamic curves.In particular, mesh and time step sizes were found to have the greatest influence on the calculated pump performance. Therefore, small time steps and large mesh sizes are recommended to obtain accurate dynamic curves. On the other hand, the influence of the simulation method was not significant in this study. This study contributes to advancing VAD simulations, ultimately enhancing clinical efficacy and patient outcomes.
医学的进步，尤其是心室辅助装置（VAD）的进步，显著改善了心力衰竭（HF）的治疗效果，提高了患者的预后。然而，一些挑战如不良事件（中风、出血和血栓）仍然存在。计算流体动力学（CFD）模拟在理解 VAD 流动动力学和 VAD 中因非生理流动条件而产生的相关流动诱导不良事件方面具有重要作用。本研究旨在验证与心血管系统相互作用的关键 CFD 模拟参数，为准确模拟 VAD 提供依据，这是在 Hahne 等人的研究基础上进行的。使用双向耦合技术对 VAD CFD 与心血管系统相互作用的动态（脉动）流动条件进行建模。系统地改变网格大小、时间步长和模拟方法（URANS、LES），以评估它们对 HeartMate 3 动态泵性能（动态曲线）的影响，旨在找到最佳的模拟配置以准确再现动态曲线。本研究还开发并应用了新的重叠比（OR）方法来量化动态曲线。特别是，网格和时间步长对计算泵性能的影响最大。因此，建议采用较小的时间步长和较大的网格尺寸来获得准确的动态曲线。另一方面，在本研究中，模拟方法的影响并不显著。本研究有助于推进 VAD 模拟，最终提高临床疗效和患者预后。
