End-stage renal disease patients needs a functional vascular access to receive hemodialysis and prolong their lives. Arteriovenous fistula (AVF) is priority consideration for hemodialysis, which is a connecting a superficial vein to a nearby artery and allowing this vein to enlarge and increase in internal diameter under arterial circulation. Unfortunately, 30-50% of fistulae fail to mature. Vascular calcification and stenosis were considered for early failure. The perivascular fat of artery can be predicted successful AVF maturation. However, Few previous studies have compared AVF maturation between perivascular the fat of cephalic vein or removal during the AVF surgery. This study evaluated whether the effect of AVF inflammation and preexisting vascular fibrosis is associated to perivascular the fat of cephalic vein. Investigators will also verify inflammation by analysis of blood and tissue samples, the association of pre-existing fibrosis, and the clinical correlation with AVF early failure. This study will enroll patients with chronic kidney disease stage 5 and stage 6 who will need maintenance-hemodialysis (HD) from Nov 2021 to Dec 2022. Investigators will use the preoperative ultrasound assessment tool to confirm the feasibility of the arm vessels for the creation of a native AVF. As a prospective randomized controlled trial of perivascular fat preservation or removal during the AVF surgery, a study assistant will help the randomization and explain the informed consent to the patient . The subjects are randomly split into two groups: the experimental group will have the perivascular fat of the target cephalic vein preserved the control group will have the fat removed before the AVF anastomosis. The survey will enroll 100 adult patients and categorize them into groups according to each AVF maturation, JAS, or FTM (see definition below) by 3 - 12 after the surgery.