ACTIVATED CLOTTING TIME IS NOT A SENSITIVE PARAMETER TO MONITOR ANTICOAGULATION WITH LOW-MOLECULAR-WEIGHT HEPARIN IN HEMODIALYSIS

To study whether the activated clotting time (ACT) is a sensitive para meter to monitor anticoagulation with low molecular weight heparin (LM WH) during hemodialysis, ACT, polymorphonuclear granulocyte-elastase, and anti-factor Xa activity were studied during 30 dialysis treatments with LMWH (35 IU/kg body weight bolus; 10 IU/h/kg). Twenty treatments were performed with Hemophan, ten with polysulfone dialyzers. No clin ically relevant clotting of dialyzers was observed, but minimal fibrin deposition was found more often in the Hemophan group (50 vs. 30%). D espite continuously elevated antifactor Xa levels (Hemophan 0.49 +/- 0 .03, polysulfone 0.62 +/- 0.01 IU/ml), a significant increase of ACT w as only demonstrated 10 min after bolus application in the Hemophan gr oup. Elevated polymorphonuclear granulocyte-elastase levels were demon strated in the Hemophan group but were linked to the presence of minim al fibrin deposits and not to the dialyzer material. We conclude that ACT is not a sensitive parameter to monitor anticoagulation with stand ard doses of LMWH.