Evaluation of the anticoagulant effect of low-molecular-weight heparins based on the anti-Xa level during haemodialysis.

Abstract

Evaluate the relationship between anti-Xa activity and anticoagulant effect, and ascertain whether accumulation of low-molecular-weight heparins (LMWH) occurs during haemodialysis. There was an observational, single-centre study among participants who received the LMWH dalteparin, enoxaparin or nadroparin. A standard haemodialysis session lasted 4 hours. All included participants had anti-Xa activity measures at 0.5 and 4 hours. Extracorporeal circuit (ECC) clotting was evaluated by visual inspection of the haemodialyser and bubble trap after each haemodialysis session. The same person was tested at three consecutive haemodialysis sessions. Overall, 90 participants were enrolled and 259 haemodialysis sessions assessed. There was no significant difference in the mean anti-Xa activity at 0.5 and 4 hours for three consecutive sessions, so LMWH accumulation did not occur. There were 69 (26.6%) sessions in which, ECC clotting was visible. Compared with the group where circuit clotting did not occur, the LMWH dose and anti-Xa activity in the group where circuit clotting occurred were significantly lower. At 0.5 hour, anti-Xa <0.88 IU/mL had significantly higher odds of ECC clotting than that at ≥0.88 IU/mL. At 4 hours, anti-Xa <0.35 IU/mL had significantly higher odds of ECC clotting than that at ≥0.35 IU/mL. We found that over three haemodialysis sessions, no significant accumulation of LMWH was evident in subjects receiving a LMWH dose of between 2000 and 5000 IU for regular. Anti-Xa activity measurement can be used to adjust the dosage of LMWH and predict the anticoagulant effect during haemodialysis.