The Creation Of A Canine Arteriovenous Fistula Model And Preliminary Experimental Study

Background and ObjectiveVascular access is the line of life for long-term maintenance dialysis patients. Native arteriovenous fistula (AVF),artificial vascular fistula,central venous catheters(CVC) are the most common vascular access for MHD patients. And the native fistula is the best maintenance of vascular access because of its longest life and least morbidity. National Kidney Foundation Disease Outcomes Quality Initiative recommended native arteriovenous fistula should be the first choice for MHD patients. The life and function of AVF is closely related to the outcome of dialysis and to the life of MHD patients. Vascular access dysfunction continues to remain a major cause of morbidity and hospitalization, vascular access dysfunction caused great pain for the MHD patients, at the same time brought heavy economic burden, even threaten the life of the patients. Many factors could cause fistula fail to maturation and late dysfunction,recent research were focus in vascular neointima hyperplasia and abnormal vascular remodeling. Vascular neointima hyperplasia will lead to vascular stenosis and thrombosis formation, and then lead to vascular access malfunction. There have been few studies regarding effective therapeutic interventions for HD vascular dysfunction at the present time, despite the magnitude of the clinical problem. This study anastomosed femoral artery and vein of domestic dogs to creat arteriovenous fistula animal model and validated this is an ideal model in which to test out novel interventions for the prevention and treatment of clinical hemodialysis vascular access dysfunction. At the same time we carried out preliminary experiments about the changes after the creation of femoral artery and vein fistula of domestic dogs. Materials and Method:12dogs were created arteriovenous fistula though anastomosed femoral artery and vein. All of the subjects were on the day of surgery, postoperative3days, one week, two weeks, four weeks early morning fasting blood samples, the Elisa method were used to test the serum endothelin-1and nitric oxide concentrations, using two-dimensional color Doppler examination clearly show anastomotic arterial and venous side of its main vessels, measuring its diameter, anastomotic diameter by ultrasound built-in software automatically calculates blood flow. Record peak blood flow.6dogs were sacrificed7days after the operation, the others were sacrificed28days after the operation. The femoral vein were harvested after canine were sacrificed and the change of the neointima were observed by microscope.Application of SPSS17.0statistical package for statistical analysis of all data, P<0.05was considered statistically significant.Results:(1) All the operation were succeed and all the arteriovenous fistula matured well.(2) The circumference of the femoral artery and femoral vein were marked enlarged3days after the operation,and tended to Progress gradually with time.(3) Blood flow volume were marked increased3days after the operation and tended to Progress gradually with time, tended to be stable at21days.(4) NO increased obviously3days after the operation, and were significantly higher than other groups (P<0.05). Intercomparison in other groups no significant difference were observed (P>0.05) The concentration of ET-1achieved peak. Compared with the day of surgery, ET-I increased significantly1,14,,21days after the surgery (P<0.05). Intercomparison in other groups no significant difference were observed (P>0.05).(5) Neointima hyperplasia were observed7days after the operation and its’thickness were25.32±3.96um. Neointima hyperplasia tended to Progress gradually with time and neointima thickness achieved195.77±27.51um at day28after the operation.Conclusion:(1) We have developed and validated a canine model of venous neointimal hyperplasia that is very similar to the human lesion. We believe that this is an ideal model in which to test out novel interventions for the prevention and treatment of clinical hemodialysis vascular access dysfunction.(2) In the early stage after the surgery the concentration of NO increased obviously,it benefits vascular remodeling and benefits arteriovenous fistula mature.7days after the surgery neointimal hyperplasia began to happen, the concentration of ET-1also increased,maybe it has a close relationship with the neointimal hyperplasia.(3) After the surgery the concentration of NO、ET-1changed and this may provided theoretical foundation for future research.