Effect of anticoagulation on blood membrane interactions during hemodialysis

Background. Adequate anticoagulation is a precondition to prevent extracorp oreal blood clotting and to improve biocompatibility during hemodialysis. I n this study, we performed a morphologic analysis by using scanning electro n microscopy to compare three modes of anticoagulation-conventional unfract ionated heparin (UFH), low molecular weight heparin (LMWH; dalteparin sodiu m), or sodium citrate during hemodialysis-on membrane-associated coagulatio n activation. Methods. Fifteen patients on regular hemodialysis therapy were investigated . Five patients received UFH, five patients LMWH, and five patients sodium citrate as an anticoagulant during a standardized hemodialysis protocol usi ng a single-use polysulfone capillary dialyzer. Membrane-associated clottin g was evaluated using a scanning electron microscope. A dialyzer clotting s core was used for quantitative description of coagulation activation on mem brane segments. Results. Using UFH as an anticoagulant revealed the most pronounced cell ad hesion and thrombus formation and the highest dialyzer clotting score (11.5 +/- 1.3 of a maximal 20 points). LMWH had a lower dialyzer clotting score than UFH (10.4 +/- 1.2 of 20 points). During the use of sodium citrate, a n egligible thrombus formation and the lowest dialyzer clotting score (1.6 +/ - 0.6 of 20 points, P < 0.05) were observed. Conclusion. The results of this investigation indicate that using sodium ci trate as an anticoagulant during hemodialysis induces a lower activation of coagulation than both conventional and fractionated heparin, which might c ontribute to an improvement of biocompatibility of hemodialysis extracorpor eal circulation.