Stenosis is the most frequent vascular access complication and is responsible for access thrombosis and thus long-term patency limitation. Regular arteriovenous graft (AVG) examination by ultrasonography and preemptive balloon angioplasty prolong AVG cumulative patency according to some, but by far not all trials. This was why the routine use of ultrasound surveillance is not recommended recently.In this review we show huge differences in the definition of stenosis significance among the trials and other probable factors, which may have caused the contradiction of the results. Without precise definition of stenosis significance, many AVGs have been undergoing unnecessary balloon interventions with high morbidity, high cost and low benefit.