BACKGROUND: Arteriovenous grafts (AVG) are the predominant form of permanent vascular access used among hemodialysis (HD) patients in North America but suffer from high intervention and complication rates associated with vascular stenosis. The fish oil inhibition of stenosis in hemodialysis grafts (FISH) study evaluates the efficacy of fish oil in improving HD graft patency.

METHODS: This study is a multi-center, randomized, double blind placebo-controlled clinical trial of 232 chronic HD patients who require a new graft access. Participants are randomized to fish oil versus placebo post-operatively. The primary endpoint is the proportion of AVG with loss of native patency within 12 months of creation. Secondary endpoints are aimed to determine the effect of fish oil on factors that may promote stenosis and thrombosis. Cumulative patency rates, survival analysis, and analysis of inflammatory markers and adverse events will provide a better understanding of the potential effect of fish oil on a patient's vascular access and cardiovascular system. The FISH study is registered at current controlled trials ( ISRCTN: 15838383.

RESULTS: Details of the study protocol are described including mechanisms of reducing bias through randomization and double blinding, sample size determination, evaluation of patient adherence, access monitoring, and the safety of using fish oil. The main challenges of designing and implementing this study, including using a natural supplement as an intervention in modern medical practice and recruitment of graft recipients in the ;fistula first' environment are discussed.

CONCLUSION: This is the first large, multicenter, randomized controlled trial of a natural supplement in preventing HD graft stenosis and thrombosis.