Use of low-dose low molecular weight heparin in hemodialysis

We investigated the lowest effective dosage of low molecular weight (LMW) heparin for hemodialysis in comparison to unfractionated (UF) heparin. Initial hemodialysis sessions were undertaken in 10 uremic patients with UF heparin of the dose habitually required for each patient. Four-hour hemodialysis sessions were then undertaken with LMW heparin (nadroparin) in a single bolus (200 anti-Xa unit Institut Choay/kg [aXaU IC/kg], 175 aXaU IC/kg, 150 aXaU IC/kg, or 125 aXaU IC/kg; two sessions for each dosage). Anti-Xa levels and activated partial thromboplastin time (APTT) were monitored hourly during dialysis. Fiber bundle volume of dialyzer was measured before and after dialysis. Urea clearance was determined at the onset and completion of dialysis. There were no episodes of excessive bleeding, clotting of dialyzers, or clots in air traps with UF heparin or LMW heparin. A 35% increase in APTT above baseline was observed in all dialysis sessions 1 hour after LMW heparin bolus, but the APTT decreased rapidly thereafter. The anti-Xa levels exceeded 0.5 U/mL for all sessions using LMW heparin irrespective of the dosage. No significant reduction of urea clearance was found in dialysis with either UF or LMW heparin. No reduction of fiber bundle volume of dialyzer was observed in dialysis with either UF or LMW heparin, although a small reduction (3%) was observed in dialysis with LMW heparin at 125 aXaU IC/kg. We concluded that the use of LMW heparin for hemodialysis is safe and effective as compared with UF heparin. The lowest effective dosage can be reduced to 125 aXaU IC/kg in high-risk patients to reduce hemorrhagic complications.