Effectiveness of Endoluminal Treatment of Autologous Arteriovenous Endovascular Fistula Failure

Inclusion Criteria: 1. Subjects aged between 18 and 75 years. 2. Subjects possess a mature upper limb autologous arteriovenous fistula (AVF) and have undergone at least one hemodialysis session. 3. Target lesion must be located in the venous segment of the upper limb AVF. 4. Doppler ultrasound confirms that the target lesion stenosis is ≥50%, accompanied by at least one of the following clinical manifestations: elevated venous pressure during dialysis, abnormal fistula signs, significant reduction in blood flow (\<200ml/min). 5. Guidewire and balloon successfully pass through the lesion and complete dilation. 6.Subjects or their legal representatives must understand the purpose of the trial, voluntarily participate in the clinical trial, and sign an informed consent form, while also being willing to adhere to the specific follow-up schedules set by this trial. Exclusion Criteria: 1. Target lesion located in the arterial segment or anastomosis of the AVF. 2. Target lesion located in the lower limb AVF. 3. Subjects with previous stent implantation in the AVF. 4. Patients diagnosed with symptomatic central venous occlusive disease: AVF flow reduction accompanied by swelling of the ipsilateral limb, chest, or facial area, with DSA confirmation of central venous occlusive disease. 5. Subjects with two or more target lesions in the AVF (when two stenoses are less than 3 cm apart, they are considered as one target lesion). 6. Subjects with acute thrombosis in the AVF or who have undergone AVF thrombolysis or thrombectomy within the past 30 days. 7. Subjects who have undergone or plan to undergo surgical intervention on the AVF within 30 days. 8. Subjects with AVF infection or concurrent systemic active infection. 9. Subjects planning renal transplantation or switching to peritoneal dialysis within the next 12 months. 10. Subjects with diseases causing coagulopathy, such as thrombocytopenic purpura. 11. Subjects undergoing immunotherapy or suspected/diagnosed with vasculitis. 12. Subjects with allergies or contraindications to heparin or contrast agents. 13. Subjects who are pregnant or breastfeeding. 14. Subjects with a life expectancy of less than 12 months.