Depurative capacity toward medium molecules of the dialyzer Toray NV-U® Hydrolink™: A new hydrophilic membrane to perform online hemodiafiltration.

INTRODUCTION

New dialysis membranes with new properties are being developed to improve efficacy and tolerance. The hemocompatibility of a polymeric biomaterial is influenced by the layer of water at the blood membrane interface. The new dialyzer TORAY NV-U® has a membrane Hydrolink™, designed to suppress platelet adhesion and to improve the hemocompatibility. Until now, there is no experience in online hemodiafiltration (OL-HDF).The objective of the present study is to evaluate the efficacy of this new membrane in OL-HDF therapy compared to another membrane commonly used. Other objectives are to evaluate the inflammatory response, hemodynamic tolerance, and the anticoagulation regimes.

METHODS

This is a prospective pilot study performed in five anuric patients receiving OL-HDF. For 1 month patients were kept with their usual dialyzer FX1000® (FMC). Subsequently, the dialyzer was changed to TORAY NV-U® (Hydrolink®) for 1 month. In the last dialysis session of each dialyzer, blood tests were performed to evaluate inflammation and depurative capacity.

RESULTS

We did not find differences in medium size removal molecules and convective volume: FX1000®: 31 ± 9 l per session and Hydrolink™ 30 ± 8 l; p = 0.7); β2microglobulin reduction ratio (RR) FX1000® FMC 83 ± 3%; Hydrolink™ 79 ± 4; p = 0.14; Myoglobin RR FX1000® FMC 72 ± 7%; Hydrolink™ 76 ± 4; p = 0.28. We did not find differences in inflammation parameters: serum IL6 with FX1000® 6.0 ± 4.2 pg/mL; Hydrolink™ 7.6 ± 5.0 pg/mL; p = 0.3.During all sessions with the two dialyzers there was adequate plasmatic filling, reaching 85 % filling. All patients had "good" dialyzer status in all dialysis sessions with TORAY NV-U®, while the dialyzer status with FX1000® was "good" in 20% of the sessions, "medium" in 30%, and "dirty" in the remaining 50% dialysis sessions.

CONCLUSIONS

The new dialyzer Hydrolink™, TORAY NV-U® is not inferior to perform OL-HDF compared to dialyzers usually used for this therapy, and could allow decrease heparin doses. Further studies with a bigger sample size and longer follow-up will answer if Hydrolink improves inflammation and assess a better hemodynamic tolerance.