Stenosis of Arteria-Venous Fistula in Maintenance Hemodialysis Patients: Early Intervention Trial

Inclusion Criteria: 1. Patients with long-term maintenance hemodialysis with AVF as the vascular access; 2. Positive clinical examination signs of AVF stenosis （not all required） : (1) the visual examination: edema, prolonged bleeding time, hematoma, aneurysm or constriction of the fistula .(2) the palpation examination: a narrowing of the outflow vein or aneurysm formation. (3) the auscultation examination: high pitch and/or discontinuous murmur; 3. Doppler ultrasound /DSA/MRA show the diameter of AVF fistula is \>50% narrow than the adjacent segment of the fistula lumen; 4. Blood flow of the AVF is \<500ml/min or monthly declines of the blood flow\>25%; 5. Patient signed the informed consent. Exclusion Criteria: 1. allergic to the iodine contrast or gadolinium contrast agent; 2. local infection; 3. the presence of severe coagulation dysfunction (or long-term history of taking warfarin or ticlopidine); 4. the presence of severe artery steal syndrome; 5. stenosis of immature fistula or fistula \<2 month after vascular anastomosis; 6. severe central venous stenosis; 7. discontinue hemodialysis treatment (such as to transfer to peritoneal dialysis or kidney transplant); 8. severe cardiac dysfunction (New York Heart Association cardiac functional classification III or worse), unstable angina pectoris, myocardial infarction, severe left ventricular hypertrophy, or severe vascular embolic disease; 9. participated in other clinical trials within 12 weeks; 10. alcohol and/or drug abusers, mental disorders; 11. patients not suitable as the subjects of this trial under the consideration of researchers.