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07-05-2012 | Cardiology | Article

Daily fish oil intake benefits patients with hemodialysis grafts

MedWire News: Daily fish oil supplementation may benefit patients with a new hemodialysis graft, show study findings.

Although daily fish oil ingestion did not decrease the proportion of grafts with patency loss, it did have beneficial effects on graft patency and rates of thrombosis and also reduced the number of corrective interventions required following placement of the grafts. Fish oil intake also demonstrated potential cardiovascular (CV) benefits.

"Thrombosis occurs in 50% of all ateriovenous grafts within 1 year after placement, necessitating a salvage procedure in more than 75%," explain Charmaine Lok (Toronto General Hospital, Ontario, Canada) and colleagues. "To date, multiple interventions have failed to convincingly or consistently reduce thrombosis rates."

The omega-3 fatty acids found in fish oils have theoretical appeal for preventing the development of arteriovenous graft stenosis and thrombosis, says the team. "The EPA [eicosapentaenoic acid] and DHA [docosahexaenoic acid] components of fish oils have been shown to have antiproliferative, antioxidant, and vasodilatory effects that may affect the pathogenesis of arteriovenous graft stenosis."

The team therefore conducted the Fish Oil Inhibition of Stenosis in Hemodialysis Grafts (FISH) study, a multicenter, randomized, placebo-controlled trial including 201 patients with end-stage renal disease who required a new arteriovenous graft for chronic hemodialysis.

Patients were randomly assigned to receive treatment with either fish oil capsules (4 g/day) or matching placebo for the 12 months following the creation of their graft. The fish oil contained 48% EPA and 25% DHA.

Patients were followed up biweekly for arteriovenous grafts with loss of native patency, defined as the graft having a primary event of thrombosis or requiring radiologic or surgical intervention to maintain patency following its creation.

As reported in JAMA, the proportion of patients with graft thrombosis or a radiologic or surgical intervention to maintain graft patency did not significantly differ between fish oil and placebo recipients.

However, the rate of patency loss was significantly lower in the fish oil compared with placebo group, at 3.43 versus 5.95 per 1000 access-days (days where there was sufficient vascular access for hemodialysis).

In addition, the frequency of thrombosis events was reduced by half in the fish oil group and the rate of corrective interventions was also significantly lower, at 1.71 versus 3.41 and 2.89 versus 4.92 per 1000 access-days, respectively.

Further analysis revealed that, compared with the placebo recipients, there was a significantly reduced risk for cardiovascular events in the fish oil recipients, at a hazard ratio of 0.43. And the fish oil recipients also had significantly greater reductions in mean systolic blood pressure.

"Although the risk of the primary end point was not significantly lower among fish oil recipients, this should be considered in the context of the apparent consistent clinical benefit observed for the secondary outcomes," say Lok et al.

"The use of fish oil to prevent cardiovascular events in the dialysis population merits further study," they add.

By Sally Robertson

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