Low molecular weight heparin versus standard heparin. A long-term study in hemodialysis and hemofiltration patients.

The influence of low molecular weight (LMW) heparin (Braun 21-23, Mulsungen, West Germany) and unfractionated standard heparin (SH) on blood clotting and other routine laboratory parameters was investigated in a 30 week cross-over study in 30 hemodialysis patients. The LMW heparin dose necessary (anti FXa-activity) for effective anticoagulation was two thirds of the standard heparin dose. Using these doses, both substances displayed identical antithrombotic effects. Complications were not seen in either group. PTT and thrombin time were only marginally effected by LMW heparin, whereas they were markedly prolonged by SH heparin. Factor VIII activity was significantly lower in the LMW heparin group as compared to the standard heparin group after 18, 24, and 30 weeks. Antithrombin III, fibrinogen, fibrin monomers, plasminogen, and alpha 2-antiplasmin were comparable in both groups. Creatinine, urea, hemoglobin, and hematocrit were also unchanged, excluding differences in dialysis efficacy or occult blood loss. Equal numbers of blood transfusions were necessary, but bleeding complications did not occur in either group. In conclusion, safe and effective dialysis can be performed using this low molecular weight heparin for anticoagulation in hemodialysis and hemofiltration. The possible benefits of LMW heparin (reduced frequency of bleeding, alleviation of hypertriglyceridemia) were not, however, apparent, possibly because of the short observation period and the low incidence of hemorrhagic complications in routine dialyses.