The goal of this clinical trial is to study effectiveness of ultrasound-guided fistuloplasty in comparison to conventional fistuloplasty in patients with arteriovenous access flow dysfunction. The main question it aims to answer is:

To investigate patencies in patients with arteriovenous access flow dysfunction receiving ultrasound-guided fistuloplasty versus fluoroscopy-guided fistuloplasty at 6 months

Participants will:

• be randomized equally to ultrasound-guided fistuloplasty group and fluoroscopy-guided fistuloplasty group.
• visit clinic at one month, three month & six months for checkups and tests.

This is an experimental study employing a prospective randomized controlled trial to determine the efficacy of ultrasound-guided fistuloplasty compared to fluoroscopy-guided fistuloplasty in patients with arteriovenous access flow dysfunction.

After assessing for eligibility, patients will be randomized equally with a ratio 1:1 to ultrasound-guided fistuloplasty group and fluoroscopy-guided fistuloplasty group.

Both interventions will be done in operation theatre to maintain sterility. After cleaning and draping the area of interest, local anaesthesia is given to the puncture site. A puncture needle is used to gain access to the arteriovenous fistula followed by a guide wire. Then, a sheath with an appropriate size is placed and a balloon catheter of adequate size is inserted over the guide wire and inflated for 2 minutes. Ultrasound is used in the subject group to monitor technical success. On table visualization of continuous segment of dilated vein to 5-6mm and continuous flow rate of more than 500ml/min signifies the end points of the procedure. Fluoroscopy is used in the control group to assess for technical success. On table fistulogram visualization of less than 30% recoil of the target lesion signifies technical success. After a satisfactory result, a figure of 8 suture is placed with manual inflow occlusion. Post procedure, patients will be observed for any signs of haematoma or bleeding. If there are no immediate complications, patients will be discharged on the same day.

Inclusion Criteria:

1. Patient able to comprehend English or Malay language.
2. Patient aged ⩾18 years and ⩽80 years.
3. Patient is willing to comply with protocol.
4. Native AVF that is able to provide prescribed dialysis consistently with 2 needles for >2/3 of dialysis sessions within 4 consecutive weeks.
5. Patient has a reasonable expectation of remaining on haemodialysis for 6 months.
6. Dampened thrill or pulsatile flow.
7. Volume flow (VF) <500 ml/min.
8. Severe stenosis (>50%) of arteriovenous (AV) access measured on color image and confirmed by peak systolic velocity (PSV) ratio of ≥3 in the inflow artery, anastomosis, or in the outflow vein.

Exclusion Criteria:

1. Prior history of fistuloplasty.
2. Thrombosed or completely occluded fistula or outflow vein.
3. Non-mature AVF.
4. Arteriovenous grafts.
5. Suspected central vein stenosis/ cephalic arch stenosis - arm edema or Doppler detected suspicion of the same.
6. Non consenting patient.
7. Metastatic cancer or terminal medical condition.
8. Limited life expectancy (<6 months).
9. Blood coagulation disorders (haemophilia/ Von Willebrand disease/ clotting factor deficiencies/ liver disease).
10. Connective tissue disease (rheumatoid arthritis/ lupus).
11. Sepsis or active infection.
12. Planned access abandonment within 6 months (eg, peritoneal dialysis or transplant).
13. Pregnant women or women of childbearing potential who are not following an effective method of contraception.
14. Allergy or other known contraindication to iodinated media contrast.
15. Patient enrolled in another access maintenance trial.

No individual participant data will be shared. Results will be published by the investigators in academic journals. Sharing of generated study data will be carried out in several different ways. We plan to make our results available to researchers and potential collaborators interested in ultrasound guided fistuloplasty.