Arterial line versus venous line administration of low molecular weight heparin, enoxaparin for prevention of thrombosis in the extracorporeal blood circuit of patients on haemodialysis or haemodiafiltration: A randomized cross-over trial.

Abstract

The objective of the study is to compare the anti-factor Xa (AXa) level in the blood, after arterial and venous line administration of equivalent doses of enoxaparin for prevention of thrombosis in the extracorporeal blood circuit. The design of the study is a dual centre, prospective, open-labelled randomized crossover, 7 weeks trial. The setting of the study is on a patient on long-term haemodialysis (HD) or haemodiafiltration (HDF) using high-flux membrane. There were eight patients on HD and eight on HDF. Participants were randomly assigned to receive enoxaparin either through the arterial line or venous line of extracorporeal blood circuit for an initial study interval of 2 weeks, followed by 2 weeks of alternate route administration. During the run-in period of 1 week and the follow-up period of 2 weeks, enoxaparin was administered through the arterial line. The primary outcome measure was to compare AXa blood level 4 h after enoxaparin administration. The secondary outcome measures were manual compression time to stop bleeding from arteriovenous fistula, extracorporeal circuit clotting and systemic bleeding episodes. The mean AXa blood level, 4 h after venous circuit administration (0.58 ± 0.21 (HD), 0.82 ± 0.29 (HDF)) of enoxaparin, was significantly greater than that after arterial administration of enoxaparin (0.39 ± 0.25 (HD), 0.39 ± 0.14 (HDF) U/mL), (P < 0.001). In patients on HD or HDF, venous line administration of enoxaparin achieves greater 4 h blood AXa level compared with arterial line administration of equivalent dose. Based on this, we suggest a 25% or 50% reduction in the dose of venous line enoxaparin, compared with the dose administered through arterial line in patients receiving either HD or HDF, respectively.