Objective The intervention of non-maturing and failing arteriovenous fistulas (AVF) is predominantly completed via the use of fluoroscopy-guided fistulaplasty. However, there is a risk to the patient as it requires the use of nephrotoxic contrast agents and radiation. The proposed study will determine the feasibility of using ultrasound-guided fistulaplasty as a viable intervention instead of conventional fluoroscopy-guided fistulaplasty. This project will determine if ultrasound can identify a stenosis within a fistula and guide the balloon catheter into the correct position. The project will assess diameter reduction and peak systolic velocity measurements at the site of stenosis pre- and post-intervention to determine the successfulness of ultrasound-guided fistulaplasty. The project will also assess changes in volume flow pre- and post-intervention volume flow measurements within the brachial artery and fistula to assess suitability for haemodialysis post-intervention. Method The project will aim to recruit at least 12 AVF patients with a simple stenosis, excluding central venous stenoses, between November 2018 and February 2019. Patients will undergo normal fluoroscopy intervention but will also have the addition of ultrasound measurements. A diagram drawn from the pre-intervention ultrasound measurements will be compared to the fluoroscopy images to compare areas which require intervention. The radiologist will also rate their confidence of correct balloon positioning and whether the intervention has been successful via the use of diameter reduction and peak systolic velocity measurements in comparison to fluoroscopy images. In addition, data will be collected to see if patients have had successful haemodialysis post-intervention.