Effective anticoagulation by a low molecular weight heparin (Fragmin) in hemodialysis with a highly permeable polysulfone membrane.

The efficacy and kinetics of a low molecular weight heparin fragment (LMWH-fragment, Fragmin) were studied during one hemodialysis session with a highly permeable polysulfone membrane and compared to a second dialysis session using a conventional cuprophane membrane. All patients received 5000 U of Fragmin given as an injection into the arterial line at start of dialysis. The anticoagulative efficacy was evaluated by measuring plasma fibrinopeptide A concentrations. LMWH-fragment concentrations in plasma and ultrafiltrate were determined by an amidolytic activity assay and by a radioimmunoassay using a monoclonal antibody. During hemodialysis with cuprophane and polysulfone membranes the fibrinopeptide A concentrations were low indicating adequate anticoagulation. LMWH concentrations in plasma did not differ in the two membranes at any time. The LMWH-fragment in the ultrafiltrate could neither be detected with the amidolytic assay nor with the radioimmunoassay. We conclude that a single injection of Fragmin effectively prevents clotting during hemodialysis with a highly polysulfone membrane. No significant amounts of the anticoagulant are lost over the dialysis membrane.