Comparison of two low-molecular weight heparins (LMWHs), tinzaparin and bemiparin, during hemodialysis

Abstract

The anticoagulant effects of two LMWHs, tinzaparin sodium and bemiparin sodium, were compared during two study dialysis (SD) sessions (SD1 with tinzaparin and SD2 with bemiparin) in ten chronic hemodialysis patients. Prior to SD1, patients had received 3,500 IU of tinzaparin in each dialysis session for two weeks. After SD1, they were switched to 3,500 IU of bemiparin for two weeks and the second study dialysis session (SD2) was carried out. Patients used the same dialyzers during the whole study period and no changes were made in any of the other hemodialysis parameters. Blood samples for the measurement of PT, aPTT and anti-Xa activity were taken before the study dialysis sessions (sample 0), and again at two and four hours after the initiation of dialysis (samples 2-h and 4-h, respectively). PT values showed no change between the SD1 and SD2 sessions, but aPTT values were significantly higher in the 2-h and 4-h samples of the SD1 session compared to corresponding values in SD2 samples (p < 0.005). Anti-Xa activity was higher in the 2-h and 4-h samples of the SD2 session compared to the SD 1 session (p = 0.005 and p = 0.012, respectively). At four hours, only patients receiving bemiparin had a mean anti-Xa activity higher than 0.40 IU/mg (mean 0.51 +/- 0.76). However, fibrin/clot formation in the extracorporeal circuit during each study period as assessed by visual inspection, did not differ significantly between sessions. It is concluded that the anticoagulant profile of bemiparin sodium during hemodialysis treatment is superior to that of tinzaparin.