COMMENTARY

If Fish Oil Can't Lower AVF Risk in Dialysis, What Can?

Tejas P. Desai, MD

Disclosures

February 03, 2017

Effect of Fish Oil Supplementation and Aspirin Use on Arteriovenous Fistula Failure in Patients Requiring Hemodialysis: A Randomized Clinical Trial

Irish AB, Viecelli AK, Hawley CM, et al; Omega-3 Fatty Acids (Fish Oils) and Aspirin in Vascular Access Outcomes in Renal Disease (FAVOURED) Study Collaborative Group
JAMA Intern Med. 2017 Jan 3. [Epub ahead of print]

It is now clear that the nephrology community has reached a consensus regarding the arteriovenous fistula (AVF)—it is the preferred dialysis access for hemodialysis patients. Indeed, an increasingly growing body of scientific evidence shows the superiority of the AVF over the more easily obtained cuffed-tunneled catheter. Naturally, this superiority results in an increasing number of AVFs created for patients with end-stage renal disease (ESRD). Ultimately, providers and patients become increasingly dependent on the function of the AVF to perform adequate hemodialysis. So it is no surprise that scientists are searching for measures that can increase the reliability of these iatrogenically created vascular constructs. The current investigation analyzes the concomitant use of fish oil and aspirin to improve AVF function.

In various prior scientific investigations, fish oil has been considered to be an anti-inflammatory, antiplatelet, and/or vasodilatory agent.[1,2] Given these multiple therapeutic effects, the investigators studied whether fish oil administration would increase the functional life of AVFs. In this investigator-initiated randomized controlled trial, 12 weeks of fish oil therapy (with or without aspirin) was given to patients with a newly created AVF. The primary outcome was the rate of AVF thrombosis, cannulation failure, or AVF abandonment by the clinician within the first 12 months after fistula creation. Thirty-five hemodialysis centers across the United Kingdom, Malaysia, and Oceania participated with a total study population of 530 patients with either stage 4 or stage 5 chronic kidney disease. Patients studied had upper extremity AVFs only, and those randomly assigned to the fish oil arm received 2 g twice daily of four omega-3 acid ethyl esters (Omacor® capsules). It should be noted that this study was terminated early because of a lack of funding to continue patient recruitment.

Nearly half of the patients in both arms suffered a fistula failure (47%). In the presence of aspirin, concurrent use of fish oil yielded no difference in the rate of fistula thrombosis (22% vs 23% in placebo + aspirin), abandonment (19% vs 22%), or cannulation failure (40% vs 39%). Disappointingly, no differences were detected in the subsequent post-hoc analyses, including the time interval between fistula creation and dialysis initiation or the time to first cannulation.

The design and results of this investigation are relevant to our practice and should not be readily dismissed because of its early termination. Despite previous trials in non-ESRD patients that have touted the provascular effects of fish oil, none of these effects could stave off fistula failure in dialysis patients. These results strengthen the theory that common anti-inflammatory and antiplatelet agents used in the prevention of vascular disease in native blood vessels are ineffective in artificial vascular creations. Therefore, until newer pharmacotherapeutic agents are discovered that provide the same provascular benefits in fistulae as we have seen in native vessels, providers and patients must continue to use clinical surveillance as the primary method of identifying a failing fistula.

Figure. Fish oil use against AVF. AVF = arteriovenous fistula. Image courtesy of Tejas P. Desai, MD.

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