Scoring Balloon and High Pressure Balloon in the Treatment of Arteriovenous Graft Stenosis

Inclusion Criteria: 1. Hemodialysis patients aged ≥18 and ≤80 years old, (Note: Hemodialysis patients in Singapore aged ≥ 21 and ≤80 years old); 2. AVG is mature and has successfully completed at least one hemodialysis treatment; 3. The target lesion is located in the AVG return vein and the venous side anastomosis; 4. The degree of stenosis of the target lesion is ≥50% (DSA visual inspection), and one of the following clinical indicators exists at the same time: Physical examination abnormalities include: open collateral veins, ipsilateral limb edema, changes in pulse characteristics, abnormal tremors, abnormal murmurs, etc.; Dialysis abnormalities include: increased venous pressure, new puncture difficulties, aspiration of thrombi, inability to reach target dialysis blood flow, prolonged haemostasis time after needle removal for 3 consecutive times, unexplained decrease in dialysis dose Kt/V (\>0.2 units), decrease in brachial artery blood flow (brachial artery blood flow \<650ml/min or decreased by 20% compared with the previous follow-up visit), etc. 5. The target lesion is primary or restenotic, consisting of one or more series of lesions, and the reference blood vessel diameter of the target lesion is between 4.0-8.0mm, and the total length of the target lesion is ≤80mm ; 6. The patient voluntarily signs the informed consent form. Exclusion Criteria: 1. The target lesion is located in the feeding artery, arterial anastomosis, artificial blood vessel puncture site, cephalic venous arch, thoracic outlet or central vein; 2. A stent has been implanted in any part of the access or there is ipsilateral central vein stenosis or occlusion that affects the function of the access; 3. Severely calcified lesions that are not expected to be dilatable with balloons; 4. Acute thrombosis or chronic total occlusion of AVG occurred at the time of enrolment; 5. The target lesion or any part of the vascular access has received PTA treatment within the last month; 6. There are thicker branch veins in the vein opening of the end-to-side anastomosis; 7. Patients who have undergone major surgical treatment within 30 days before inclusion in the study; 8. Patients known to be allergic to or intolerant to contrast media; 9. Patients receiving glucocorticoids or immunosuppressants; 10. The patient's life expectancy is less than 1 year; 11. Patients planning kidney transplantation or switching to peritoneal dialysis; 12. The degree of stenosis in the puncture point area is \>50%； 13. Patients with infection or other medical conditions that make the investigator think they are not suitable to participate in this study; 14. Those who have participated in clinical trials of other drugs or devices but have not completed them.