Abstract: Objective   To reveal the rules of vascular intima and shear force changes in the autologous arteriovenous fistula failure.  Methods   C57BL/6 mice were divided into sham operation group (n=20) and surgical group (n=20). The operation group were subjected to a microsurgery to establish an internal arteriovenous fistula between carotid artery and jugular vein, while the sham group did not have the fistula. The examination indicators after the surgery included  ①hemodynamics: arterial pressure, heart rate, blood flow velocity and shear stress value; ②histopathology: thickness of the venous wall by HE staining, mucopolysaccharide in vascular wall by PAS staining, damage of reticular fibers in vascular wall by Gomori silver staining, damage of elastic fibers in vascular wall by aldehyde-fuchsin elastic fiber staining, and changes of vascular endothelial cells by CD31 and CD34 immunostaining.  Results   ①Hemodynamics: Compared with the sham group, the inner diameter of the carotid artery shrank, and the vascular shear stress increased significantly (t=-6.840, P<0.001) in the operation group. ②Histopathology: In the operation group, pathological findings included thickened wall and narrowed lumen of the vein by HE staining, increased neutral mucopolysaccharide by PAS staining, evident fibrosis by Gomori silver staining, proliferation and disarrangement of elastic fibers by aldehyde-fuchsin elastic fiber staining, and interrupted endothelial cell layer by proliferated fibrous tissues in CD31 and CD34 immunostaining.  Conclusion  After arteriovenous fistula surgery, the increased shear stress in the fistula, the intimal hyperplasia, the proliferation and disarrangement of fibrous tissues and the infiltration of inflammatory cells lead to the thickness of the vessel wall and the stenosis of the vessel lumen, which account for the failure of autologous arteriovenous fistula in maintenance hemodialysis patients.

Key words: Shear stress, Autogenous arteriovenous fistula, Intimal hyperplasia and stenosis, Failure of internal fistula