Introduction: Characteristics of hemodynamics strongly affect the patency of arteriovenous fistula (AVF) in hemodialysis patients. Because of pressure balance changes among arteries after AVF construction, regurgitating flow occurs in some patients. Methods: Based on phase-contrast MRI measurements, flow types around the anastomotic site are classified to the three different types of splitting, merging, and one-way, where merging type incorporates regurgitating flow. We have performed computational simulations to analyze characteristic differences among these types. Results: In the merging type, a characteristic spiral flow is observed in AVF causing strong wall shear stress and large pressure drop, whereas the splitting type shows a smooth flow and gives a smaller pressure drop. The one-way case is intermediate between splitting and merging types. Conclusion: Regurgitation brings about high wall shear stress near the anastomotic site because of instabilities induced by merging phenomena, for which type careful follow-up examinations are regarded as necessary.

翻译：引言：血流动力学特征对维持性血液透析患者动静脉瘘的通畅性有重要影响。由于动静脉瘘构建后动脉间压力平衡改变，部分患者出现返流。方法：基于相位对比磁共振成像测量，将吻合口周围的血流类型分为三种：分流型、汇合型和单向型，其中汇合型包含返流。通过计算模拟分析这些类型之间的特征差异。结果：汇合型在动静脉瘘中观察到特征性螺旋流，引起高壁面剪切应力和大压降，而分流型血流平稳、压降较小。单向型介于分流型与汇合型之间。结论：返流因汇合现象引发的不稳定性导致吻合口附近出现高壁面剪切应力，对此类患者认为有必要进行仔细的随访检查。