Background: In coronary artery bypass grafting (CABG), the patency of venous sequential graft remains controversial. Hemodynamic factors have been proved to be the important factors influencing graft patency. The objective of this study is to compare the patency of sequential grafts and normal grafts by hemodynamic environment. Methods: This study used a patient’s clinical data to construct a 0D/3D coupled multi-scale model, and used this model to calculate graft’s hemodynamics under two grafting methods. Meanwhile, CABG ideal models were constructed based on grafts’ flow data of 60 patients (63 normal grafts, 19 sequential grafts) to calculate grafts’ hemodynamics. Results: Based on the multi-scale model, it was found that the sequential graft flow and time average wall shear stress (TAWSS) were higher than normal graft, which was good for graft patency. But there were a flow separation region, some regions of high oscillatory shear index (OSI) and relative residence time (RRT) in sequential graft, which could lead to intimal hyperplasia. Based on ideal CABG models, it was known that failure rate of sequential and normal grafts were 36.8% and 36.5%, and there were significant differences between them in flow rate, TAWSS and OSI (sequential versus normal: flow rate (ml/min): [Formula: see text] versus [Formula: see text], TAWSS (Pa): [Formula: see text] versus [Formula: see text], OSI: 0.[Formula: see text] versus [Formula: see text]). Conclusion: For saphenous venous graft (SVG), although the normal graft has similar patency with the sequential graft, the hemodynamic mechanism behind it is different. In flow rate and WSS, sequential grafts have an advantage over normal grafts. But there are high OSI and RRT regions in sequential grafts.

中文翻译：

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基于血流动力学的静脉序贯与正常移植物通畅率比较

背景：在冠状动脉旁路移植术（CABG）中，静脉序贯移植物的通畅性仍存在争议。血流动力学因素已被证明是影响移植物通畅的重要因素。本研究的目的是通过血流动力学环境比较顺序移植物和正常移植物的通畅性。方法：本研究利用患者的临床资料，构建了一个0D/3D耦合的多尺度模型，并用该模型计算了两种移植方法下移植物的血流动力学。同时，基于60例患者（63例正常移植物，19例序贯移植物）的移植物血流数据构建CABG理想模型，计算移植物血流动力学。结果：基于多尺度模型，发现序贯接枝流动和时间平均壁剪应力（TAWSS）高于正常接枝，这有利于移植物通畅。但在序贯移植中存在流动分离区、一些高振荡剪切指数（OSI）和相对停留时间（RRT）的区域，可能导致内膜增生。基于理想的CABG模型，已知序贯和正常移植物的失败率分别为36.8%和36.5%，在流速、TAWSS和OSI（序贯与正常：流速（ml/min） : [公式：见正文] 与 [公式：见正文]，TAWSS (Pa)：[公式：见正文] 与 [公式：见正文]，OSI：0.[公式：见正文] 与 [公式：见正文]）。结论：对于大隐静脉移植物（SVG），虽然正常移植物与序贯移植物的通畅性相似，但其背后的血流动力学机制不同。在流量和 WSS 中，顺序移植比正常移植具有优势。但在连续移植物中存在高 OSI 和 RRT 区域。