Department of Biomedical Engineering, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands.
Eindhoven University of Technology, Department of Biomedical Engineering, Eindhoven, Netherlands.
Int J Numer Method Biomed Eng. 2021 Feb;37(2):e3423. doi: 10.1002/cnm.3423. Epub 2020 Dec 9.
Disturbed flow and the resulting non-physiological wall shear stress (WSS) at the graft-vein anastomosis play an important role in arteriovenous graft (AVG) patency loss. Modifying graft geometry with helical features is a popular approach to minimise the occurrence of detrimental haemodynamics and to potentially increase graft longevity. Haemodynamic optimisation of AVGs typically requires many computationally expensive computational fluid dynamics (CFD) simulations to evaluate haemodynamic performance of different graft designs. In this study, we aimed to develop a haemodynamically optimised AVG by using an efficient meta-modelling approach. A training dataset containing CFD evaluations of 103 graft designs with helical features was used to develop computationally low-cost meta-models for haemodynamic metrics related to graft dysfunction. During optimisation, the meta-models replaced CFD simulations that were otherwise needed to evaluate the haemodynamic performance of possible graft designs. After optimisation, haemodynamic performance of the optimised graft design was verified using a CFD simulation. The obtained optimised graft design contained both a helical graft centreline and helical ridge. Using the optimised design, the magnitude of flow disturbances and the size of the anastomotic areas exposed to non-physiological WSS was successfully reduced compared to a regular straight graft. Our meta-modelling approach allowed to reduce the total number of CFD model evaluations required for our design optimisation by approximately a factor 2000. The applied efficient meta-modelling technique was successful in identifying an optimal, helical graft design at relatively low computational costs. Future studies should evaluate the in vivo benefits of the developed graft design.
吻合口处的血流紊乱和由此产生的非生理壁切应力（WSS）在移植物-静脉吻合口通畅性丧失中起着重要作用。用螺旋特征来改变移植物的几何形状是一种减少有害血流动力学发生的常用方法，并有可能增加移植物的寿命。动静脉移植物的血流动力学优化通常需要进行许多计算成本高昂的计算流体动力学（CFD）模拟，以评估不同移植物设计的血流动力学性能。在这项研究中，我们旨在通过使用高效的元建模方法来开发血流动力学优化的动静脉移植物。使用包含 103 个具有螺旋特征的移植物设计的 CFD 评估的训练数据集，开发了与移植物功能障碍相关的血流动力学指标的计算成本低的元模型。在优化过程中，元模型取代了 CFD 模拟，否则需要使用 CFD 模拟来评估可能的移植物设计的血流动力学性能。优化后，使用 CFD 模拟验证了优化的移植物设计的血流动力学性能。优化的移植物设计既包含螺旋移植物中心线，也包含螺旋脊。与常规的直移植物相比，使用优化的设计成功地减少了流动干扰的幅度和暴露于非生理 WSS 的吻合区域的大小。我们的元建模方法使我们的设计优化所需的 CFD 模型评估总数减少了大约 2000 倍。所应用的高效元建模技术成功地以相对较低的计算成本确定了最佳的螺旋移植物设计。未来的研究应评估所开发的移植物设计的体内益处。
