Trisodium citrate: an alternative to unfractionated heparin for hemodialysis catheter dwells

The use of tunneled hemodialysis catheters, or permcaths, either for temporary dialysis access before arteriovenous fistula or arteriovenous graft maturation or for long-term dialysis access, is associated with increased risk of catheter clotting and infection. Catheter locking solutions are routinely used to maintain patency in these catheters between dialysis sessions. Unfractionated heparin has traditionally been used for this purpose; however, trisodium citrate (also known as sodium citrate or citrate) has recently been shown to be an efficacious alternative to heparin as a locking solution. Citrate exerts both its anticoagulant and antimicrobial properties by chelating calcium to disrupt the normal coagulation pathway and by interfering with the formation of biofilm and the bacterial cell wall. Citrate is at least equivalent to heparin as an anticoagulant and antimicrobial agent for catheter locking, and in some clinical studies citrate was shown to be superior. Two different concentrations of sodium citrate were previously available; however, concerns of safety led to the removal of citrate 46.7% from the United States and Canadian markets in 2000, leaving only citrate 4% available for use as a catheter locking solution. The systemic hypocalcemic effects that were reported with citrate 46.7% have not been observed with citrate 4% in clinical trials, and the risk of systemic anticoagulation and bleeding was shown to be lower than that with unfractionated heparin. In addition, most comparative cost data indicate that citrate is a more cost-effective alternative than heparin; however, costs can vary by institution. Despite inconclusive evidence of clinical superiority, citrate 4% appears to provide a safe and at least equivocal alternative to heparin as a catheter locking agent.