Evaluation of coagulation and anti-Xa factor when using a heparin-coated AN69ST® dialyser.

Background: Hemodialysis systems are potentially thrombogenic, so it is routinely used anticoagulation. Its prescription is with risks though which the recommendations regarding the scheduled dose are still based on very different criteria.

Methods: We performed a randomized, crossover pilot study. Six patients underwent six sessions of post-dilution hemodiafiltration with polysulfone HF80® dialyzer and standard anticoagulation with nadroparin, and six sessions with heparin-coated poliacrylonitrile AN69ST® membrane without using systemic anticoagulation. Dialyser and the extracorporeal circuit clotting grade was evaluated through visual scale every hour and coagulation parameters like anti-Xa factor. Our endpoint was to assess anti-Xa activity without differences in the rate of massive clotting between the two groups.

Results: No complete or grade 4 dialyzer clotting occurred in any of 36 sessions with each dialyzer. A partial lower 25% (grade 1-2) dialyzer clotting was in 32 (89.7%) AN69ST® sessions and 35 (97.2%) with the usual dialyzer and upper 25% (grade 3-4) in 4 (11.1%) AN69ST® sessions and 1 (2.8%) dialysis session with heparin. Arterial chamber blood coagulation was not greater than 25% (grade 3 and 4) in any of the studied sessions and the venous chamber in only 1 (2.8%) session with the usual dialyzer and 3 (8.4%) with no differences AN69ST® between the two dialyzers. The activated partial thromboplastin time at two hours showed differences between techniques related to administration of low molecular weight heparin (33.3 ± 2.7s with polysulfone and 27.5 ± 2.3s in AN69ST®; P < 0.05) which remained significant at the end of the session (29.8 ± 2.1s with polysulfone and 27.2 ± 1.8s with AN69ST®; P < 0.05). Anti-Xa factor activity was maximal two hours after administration of nadroparin, with differences between the two dialyzers (0.46 ± 0.13 IU / ml in dialysis with polysulfone and 0.04 ± 0.04 IU / ml with AN69ST®p<0.005) and went down after 4 hours (0.17 ± 0.12 IU / ml in dialysis with polysulfone and 0.02 ± 0.03 IU / ml in AN69ST®; p<0.05). One patient in dialysis AN69ST®; had an adverse reaction characterized by generalized pruritus and was excluded from the study, by withdrawing the consent in the first session.

Conclusion: We demonstrate the low thrombogenicity of the AN69ST®; dialyzer that allows post-dilution hemodiafiltration sessions without systemic anticoagulation, and without increasing the frequency of severe clotting events compared to HF80®; dialyzer with nadroparin and with less risk of bleeding by not modifying the anti-Xa factor activity.