The purpose of this study is to compare the effect of DSA guided percutaneous balloon dilatation, ultrasound guided percutaneous balloon dilatation and surgical repair in the treatment of Stenosis of Arteria-Venous Fistula in Maintenance Hemodialysis Patients.

Eligibility 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/magnetic resonance angiography 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.

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.