Polycarbonate versus Cuprophan Dialyzers: Effect on Platelet Function

Abstract

Despite the use of various modalities of heparinization, bleeding episodes constitute a treat during hemodialysis in high-risk patients. The bleeding tendency may not only be due to the effect of heparin per se, but also reflect platelet injury elicited by interaction between platelets and foreign surfaces in the extracorporeal circuit. Accordingly, decline in platelet count, extraction of platelets in the dialyzer, decrease in platelet aggregation and increase in plasma levels of beta-thromboglobulin and antithrombin III (AT III) attend hemodialysis. In the present study, 12 patients were studied during two successive dialyses using membranes based on cuprophan (CP) and polycarbonate (PC). Indicating extraction of platelets in the dialyzer, hemodialysis with CP membranes induced a decline in platelet count during the 1 st h of treatment. The platelet count was, however, unchanged during dialysis with PC membranes. Irrespective of the membrane material, hemodialysis was associated with platelet injury as reflected by intradialytic deterioration of platelet aggregation and rise in plasma beta-thromboglobulin. Both immunological AT III and AT III activity were unchanged during dialysis. The results stress the need for continued search for biologically inert dialyzer membrane materials.

Dialysis Membranes and Coagulation System

“…RIA as described previously [45] was in the range reported by other authors [44]. The percent rise of (3-thromboglobuIin with time, if anything, was somewhat higher with poly carbonate although the difference was not significant.…”

“…As further evidence for less thrombogenicity of polycarbonate versus cuprophane mem branes they noted diminished platelet adhe sion onto the membrane when studied by scanning electron microscopy. More recently, this observation was confirmed by Knudsen and Nielsen [44] who saw a transient mild early fall of thrombocytes from 171,000 to 153,000/pl with cuprophane but not with polycarbonate dialyzers.…”

“…Two groups compared cuprophane and polycarbonate dialyzers and found no differ ence in the rise of (3-thromboglobulin as indi cator of platelet release reaction [43,44], However, Sreeharan et al [43] noted a fall of thrombocytes with cuprophane membranes but not with polycarbonate membranes. As further evidence for less thrombogenicity of polycarbonate versus cuprophane mem branes they noted diminished platelet adhe sion onto the membrane when studied by scanning electron microscopy.…”

Biocompatibility of a New Polycarbonate Dialysis Membrane

“…Complement and leuko cyte function was investigated by specific de termination of plasma concentrations of C3d and C5a, and release of granulocyte-derived elastase was followed as changes in plasma concentration of elastase bound to a (-pro teinase inhibitor (E-ct|Pl). The results have previously been reported in detail [5,6],…”

“…ADP-induced platelet aggregation was studied ac cording to Born and Cross [7] as previously described [5]. Aggregation was induced with ADP in final con centration of 5 pmmol/l and assessed as rate of aggre gation and degree of aggregation after 2 min.…”