Low molecular weight heparin in hemodialysis patients with a bleeding tendency

Efficacy and safety of a low-molecular-weight heparin (LMWH) were studied i n 33 stable maintenance hemodialysis patients who had a bleeding tendency o n unfractionated heparin. The optimal dose of LMWH for each patient was tit rated before the study; the mean total LMWH dosage was 1,152 +/- 574 IU. No major bleeding or clot formation was noted in a total of 2,470 hemodialysi s sessions during 6 months of LMWH administration. The mean value of plasma anti-factor Xa (anti-Xa) activity increased from 0.05 +/- 0.03 IU/ml befor e dialysis to 0.34 +/- 0.28 IU/ml after 2 h of dialysis and returned to 0.1 5 +/- 0.09 IU/ml after 4 h of dialysis; the mean activated partial thrombop lastin time was 26.1 +/- 4.4 s before dialysis, 30.7 +/- 9.5 s (an 18% incr ease) after 2 h of dialysis, and 26.2 +/- 4.4 s after 4 h of dialysis. No s ignificant change in serum antithrombin levels was noted throughout the who le study period. We conclude that a low dosage of LMWH is safe and effectiv e in hemodialysis patients who have a risk of bleeding with unfractionated heparin. Serum anti-Xa activity is better than activated partial thrombopla stin time and antithrombin in assessing the optimal dose of LMWH. A plasma anti-Xa activity of 0.37 IU/ml after 2h of hemodialysis may represent an op timal dosage of LMWH for most patients. Copyright (C) 2000 S. Karger AG, Ba sel.