Recurrent stenosis in hemodialysis access graft (AVG) is difficult to treat. For recurrent stenosis in the anastomotic junction can be treated by stent graft to improve long-term patency. However, there is no data regarding treatment of stent graft restenosis in AVG. This randomized trial is designed to compare the efficacy and safety of drug-coated balloon (DCB) versus regular balloon in AVG stent graft restenosis.

Prosthetic arteriovenous hemodialysis access graft (AVG) has high incidences of venous anastomotic stenosis and access failure. A stent graft can be used in AVG with recurrent venous anastomotic stenosis to improve long-term patency rate. However, after stent graft implementation, the effective treatment for restenosis in a stent graft is still unknown. This randomized trial is designed to evaluate the efficacy and safety of drug-coated balloon versus regular balloon for in-stent restenosis in stent graft. The investigators plan to enroll 40 patients who presented with prosthetic AVG in-stent restenosis, and then to evaluate the restenosis lesions by intravascular ultrasound. Patients will be randomized into two groups of treatment: drug-coated balloon angioplasty or regular balloon angioplasty.

Inclusion Criteria:

• Age of 20 to 90 years on regular hemodialysis at least 3 months
• Had stent graft implemented at dialysis vascular access
• Angiographic evidence of stenosis within the stent graft or less than 2 cm from the stent graft edge
• Clinical evidence of a hemodynamically significant stenosis or thrombosis
• Patient is able to provide written informed consent

Exclusion Criteria:

• Elbow fracture or any disease involve the elbow joint that prohibits the flexion maneuver.
• Target lesion cannot be crossed by the guide wire.
• Known hypersensitivity to heparin or contrast medium.
• Bleeding diathesis.
• Patients participating in another clinical trial with interfering with this trial in the past three months.
• Untreatable bleeding diathesis.
• Other diseases, such as cancer, liver disease, or cardiac insufficiency, which may lead to protocol violations or markedly shorten a patient's life expectancy (less than 3 months).
• Patients unable or unwilling to participate this trial.
• Pregnancy, lactating woman, non-adult, criminals in sentence, psychiatric patients, research staffs or colleagues are prohibited.

The IVUS interpreter and follow-up evaluators are masked.