Heparin-free hemodialysis with a polyacrylonitrile membrane

The low in vitro thrombogenicity of polyacrylonitrile (AN-69) membrane may offer the possibility of performing hemodialysis (HD) with little or no heparin. The authors sought to reduce heparin dosage using AN-69 dialyzers at blood flows of 400 to 600 ml/min. Over a 90 day period, 2228 HDs were performed: 1531 (69%) with AN-69, 528 (24%) with regenerated cellulose (RC), and 169 (8%) with cellulose acetate (CA) dialyzers. Two hundred and eighty-three HDs were performed without systemic heparin; blood compartments were prerinsed with 2,000 U heparin in 1,000 ml of 0.9% saline. Saline flushes were used in cases of rising venous drip chamber pressures or visible clotting. Incidence of clotting overall in AN-69 HDs was 0.52% (8/1531), 2.8% (15/528) with RC, and 11.2% (19/169) with CA. In heparin-free HDs, incidence with AN-69 was 1.3% (3/230), 28.6% with RC (4/14), and 25.6% with CA (10/39). AN-69 remained less thrombogenic when HDs were stratified by blood flow rate and vascular access was used. Urea clearance was no different in conventional and heparin-free treatments. Blood flow rates of 400 ml/min or higher had an independent antithrombogenic effect. It was concluded that the combination of high blood flow with AN-69 membrane allows marked reduction of HD heparin dose and safe routine use of heparin-free HD.