β-Thromboglobulin and platelet factor-4 levels during hemodialysis with polyacrilonitrile

The release of the platelet-specific proteins β-thromboglobulin (BTG) and Platelet Factor-4 (PF-4) was assessed in patients undergoing hemodialysis with standard cuprophane or regenerated cellulose membranes and then reassessed while the same patients were dialyzed with the polyacrilonitrile AN-69 membrane. Both cuprophane and regenerated cellulose produced significant increases in BTG levels above predialysis concentrations within the first hour of the procedure (median: 25.5 ng/ml; range: 9 to 53 ng/ml; P<0.05), whereas the AN-69 membrane did not (median: -2 ng/ml; range: -1 to -33 ng/ml; P not significant). Moreover, following six weeks of hemodialysis with the AN-69 dialyzer, predialysis BTG concentrations were significantly lower than during treatment with cuprophane or regenerated cellulose (120.0 mg/ml; range: 100 to 141 ng/ml vs. 163.5 ng/ml; range: 132 to 233 ng/ml P<0.05). The effect on PF-4, however, was identical with all membranes, with significant increases occurring within the first hour of hemodialysis and no changes in the predialysis levels. The dissociation between PF-4 and BTG is likely due to heparin-induced release of bound PF-4 from endothelial cells at the beginning of hemodialysis. The author's observations suggest that extracorporeal circulation of blood through a polyacrilonitrile membrane results in less platelet aggregation than a similar procedure with cuprophane or regenerated cellulose.