In the Cochrane Library’s Database of Systematic Reviews, a team of investigators recently analyzed the current research on blood flow and omega‐3 fatty acid supplementation in patients with end-stage chronic kidney disease (CKD) undergoing hemodialysis.* No significant effect was found.

Omega-3 Fats and Dialysis

Patients with chronic kidney disease (CKD) gradually lose kidney function and, by the final disease stage, may require hemodialysis to purify the blood. Patients requiring hemodialysis need effective blood circulation between their bodies and the hemodialysis machine. High blood flow rates are maintained when blood vessels are healthy; yet, blood clots can block blood flow in thrombosis, or slow blood flow by a narrowing of the vein called stenosis.

Omega‐3 fatty acids have many beneficial properties, including improvement of blood vessel function. Supplementation of food with omega‐3 fatty acids in the form of fish oil may help to reduce the risk of thrombosis and stenosis by increasing the blood’s fluidity. The blood should also flow smoothly through the artificial connections between a patient’s vessels and the hemodialysis machine. Different types of connections may be used. Some patients may have arteriovenous grafts (AVGs), while others may have arteriovenous fistulas (AVFs).

An AVG is an artificial prosthetic segment used to connect an artery and vein for hemodialysis. The graft is usually used when the vessels are too small for a fistula, or when the vessels are blocked. AVGs can be placed in the upper and lower arm, and thigh regions. An AVF is a surgical connection made to increase flow and pressure and cause veins to enlarge. The enlarged veins are able to deliver a higher amount of blood required for hemodialysis.

The authors analyzed the effectiveness and safety of omega‐3 fatty acid fish oil supplements versus placebo in hemodialysis patients with end-stage CKD who had either AVGs or AVFs. 

What They Found

• Just five clinical studies with 833 total participants were found, with results measured over six months to a year.
• In AVG patients, four studies left the authors with strong certainty that omega‐3 fatty acids did not improve blood flow nor cause patient harm, except for possible mild gastrointestinal side effects (example, gas and bloating).
• In AVF patients, one study provided moderate certainty that fish oil had no effect on blood vessel blockage or cause patient harm.

The authors noted the lack of high quality data concerning omega-3 fats and blood vessel access in end-stage CKD. “All the evidence for preventing blockages comes from just one or two studies, so more and better quality studies are needed.”

Find the research article in the Cochrane Database of Systematic Reviews.

*Tam, K.W.; Wu, M.Y.; Siddiqui, F.J.; et al. (2018, November 18). Omega-3 fatty acids for dialysis vascular access outcomes in patients with chronic kidney disease. Cochrane Database of Systematic Reviews.