SIroliMus Coated angioPlasty Versus Plain Balloon Angioplasty in the tREatment of dialySis acceSs dysfunctION (IMPRESSION): Study Protocol for a Randomized Controlled Trial
Authors: Pang Suh Chien , Tan Ru Yu , Choke Edward , Ho Jackie , Hiong Tay Kiang , Gogna Apoorva , Arani Farah Gillan , Zhuang Kun Da , Toh Luke , Chan Shaun , Krishnan Pradesh , Lee Kristen Alexa , Leong Sum , Lo Richard , Patel Ankur , Tan Bien Soo , Too Chow Wei , Chua Jasmine , Tng Alvin , Tang Tjun Yip , Chng Siew Ping , Chong Tze Tec , Tay Hsien Tsung , Yap Hao Yun , Wong Julian , Dharmaraj Rajesh Babu , Ng Jun Jie , Gopinathan Anil , Loh Stanley , Ong Shao Jin , Yoong Gary , Tay Jia Sheng , Chong Kay Yuan , Tan Chieh Suai 
Published: August 2021

Abstract
BackgroundPercutaneous transluminal angioplasty is the current standard treatment for arteriovenous fistula (AVF) stenosis. The mid- and long-term patency with plain old balloon angioplasty (POBA) is however far from satisfactory. While paclitaxel-coated balloon angioplasty has been shown to be superior to POBA, concern over its safety profile has recently arisen after reported possible increased mortality risk with a meta-analysis of large lower limb studies. An angioplasty balloon with a new type of drug coating, the sirolimus coated balloon (SCB) has been proven to improve patency in the coronary arteries. However, its effect on AV access has yet to be studied. Methods/DesignThis is an investigator-initiated, prospective, multicenter, doubled blinded, randomized controlled clinical trial to assess the effectiveness of SCB compared to POBA in improving the patency of AVF after angioplasty. A total of 170 patients with mature AVF that requires PTA due to AVF dysfunction will be randomly assigned to treatment with a SCB or POBA at a 1:1 ratio, stratified by location of AVF and followed-up for up to 1 year. Inclusion criteria includes (1) adult patient aged 21 to 85 years who requires balloon angioplasty for dysfunctional arteriovenous fistula, (2) matured AVF, defined as being in use for at least 1 month prior to the angioplasty, (3) successful angioplasty of the underlying stenosis with POBA, defined as less than 30% residual stenosis on Digital Subtraction Angiography (DSA) and restoration of thrill in the AVF on clinical examination. Exclusion criteria include thrombosed or partially thrombosed access circuit at the time of treatment, presence of symptomatic or angiographically significant central vein stenosis that require treatment with more than 30% residual stenosis post angioplasty, and existing stent placement within the AVF circuit. The primary end point of the study is access circuit primary patency at 6 months. The secondary end points are target lesion primary patency, circuit assisted primary patency, circuit secondary patency at 3,6 and 12 months, target lesion restenosis rate at 6 months, total number of interventions, complication rate and cost effectiveness. The trial is supported by Concept Medical. DiscussionThis study will evaluate the clinical efficacy and safety of SCB compared to POBA in the treatment of AVF stenosis in hemodialysis patients.Trial registration: ClinicalTrials.gov Identifier: NCT04409912 on 1 June 2020https://clinicaltrials.gov/ct2/show/NCT04409912Protocol Version: 4