The Interface Group, Institute of Physiology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
Product Development Group Zurich, Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland.
Ann Biomed Eng. 2018 Mar;46(3):417-428. doi: 10.1007/s10439-017-1951-0. Epub 2017 Nov 1.
Patients with ventricular assist devices still suffer from high rates of adverse events. Since many of these complications are linked to the flow field within the pump, optimization of the device geometry is essential. To investigate design aspects that influence the flow field, we developed a centrifugal blood pump using industrial guidelines. We then systematically varied selected design parameters and investigated their effects on hemodynamics and hydraulic performance using computational fluid dynamics. We analysed the flow fields based on Eulerian and Lagrangian features, shear stress histograms and six indicators of hemocompatibility. Within the investigated range of clearance gaps (50-500 µm), number of impeller blades (4-7), and semi-open versus closed shroud design, we found association of potentially damaging shear stress conditions with larger gap size and more blades. The extent of stagnation and recirculation zones was reduced with lower numbers of blades and a semi-open impeller, but it was increased with smaller clearance. The Lagrangian hemolysis index, a metric commonly applied to estimate blood damage, showed a negative correlation with hydraulic efficiency and no correlation with the Eulerian threshold-based metric.
心室辅助设备的患者仍然面临高不良事件发生率。由于这些并发症中的许多都与泵内的流场有关，因此优化设备的几何形状是至关重要的。为了研究影响流场的设计方面，我们使用工业指南开发了一种离心式血泵。然后，我们系统地改变了选定的设计参数，并使用计算流体动力学研究了它们对血液动力学和水力性能的影响。我们根据欧拉和拉格朗日特征、剪切应力直方图以及六个血液相容性指标对流场进行了分析。在所研究的间隙（50-500μm）、叶轮叶片数量（4-7）和半开式与闭式叶轮罩设计范围内，我们发现潜在破坏性剪切应力条件与较大的间隙尺寸和更多叶片有关。随着叶片数量的减少和半开式叶轮，停滞和回流区的程度降低，但随着间隙的减小而增加。拉格朗日溶血指数是一种常用于估计血液损伤的指标，它与水力效率呈负相关，与基于欧拉的阈值指标无关。
