Study Evaluating the Safety and Efficacy of Tri-wire Balloon for Treatment of Dysfunctional AV Fistula

Inclusion Criteria: 1. Age≥18 years; 2. Able to understand the purpose of the study, willing to participate and sign the informed consent, able and willing to accept the follow-up; 3. Indications of percutaneous transluminal angioplasty for target lesion: target lesion shows \>50% narrowing relative to adjacent normal vein diameter by angiography or ultrasound with one of the indicators listed in KDOQI vascular access guideline 2019 update Table 13.2. 4. Reference vessel diameter of target lesion from 3.0 mm to 8.0 mm. 5. Target lesion located from proximal to the anastomosis to the reflux vein at the distal end of the subclavian vein. 6. De novo or restenosis lesion. 7. Single or tandem lesion, length of which ≤ 60mm. Exclusion Criteria: 1. Women who are pregnant, nursing, or planning to become pregnant during the study. 2. Patients who have accepted major surgeries within 30 days prior to the enrollment. (such as thoracic surgery, cranial surgery). 3. Patients who plan to accept major surgeries within 30 days after the enrollment. (such as thoracic surgery, cranial surgery). 4. Occlusion lesion or thrombosis. 5. Infected fistula or severe systemic infection. 6. Patients who suffer from central venous diseases. 7. Patients known to be allergic or contraindicated to contrast agents. 8. Patients who have participated in another clinical trial within 3 months prior to the study, or previous enrollment in this study. 9. Subject has another medical condition, which, in the opinion of the Investigator, may cause him/her to be noncompliant with the protocol or confound the data interpretation.