Collaborative Study on Outcome of Antioxidant Vitamines, Microinflammation Parameters and Middle-high Toxins in ESRD Patients Treated With Online HDF, HFR and SUPRA-HFR

Today, as the research work of EUTOX group highlights, large cytokines and protein-bound solutes are gaining a relevant attention because of their emerging role as mortality predictors.

Online hemodiafiltration (online HDF) has demonstrated to offer a significant depuration for small and middle toxins, but removal of protein-bound solutes is scarce. Synthetic high-flux membranes do not allow infact significant removal of molecules heavier than 15-20 KDa. Super-flux membranes may enhance online HDF convective transport but it would surely expose the patient to unacceptable losses of albumin, vitamines and aminoacids because of the non selectivity of the convective transport.

HFR is a renal replacement therapy that utilizes convection, diffusion and adsorption. It uses a double-stage filter that consists of a high-flux polyethersulfone hemofilter in the first convective stage and a low-flux polyethersulfone filter in the second diffusive stage. The stages of the filter allow complete separation of convection from diffusion. The convective part of the first stage allows pure ultrafiltrate (UF) to pass through a sorbent resin cartridge. The first convective/adsorption stage has no net fluid removal. The blood and reinfused clean UF then undergo traditional dialysis. The second stage works by classicaHD and in this final stage the weight loss occurs. HFR has demonstrated in various clinical trials to reduce the microinflammatory state with no albumin loss and minimal aminoacids losses, thanks to the high selectivity of the resin sorbent.

SUPRA-HFR is a newly developed HDF therapy based on the HFR concept scheme, which includes a super-flux membrane in the first section, coupled with an empowered resin sorbent. This should significantly enhance large solutes depuration, overcoming online HDF flaws.

Therefore we proposed a prospective, multicenter, randomized study comparing online HDF, standard HFR and SUPRA-HFR. After a wash-out stabilization period of 4 months in post-dilution online HDF, an expected number of 50 patients will be randomized either in standard HFR (25) or in SUPRA-HFR (25) and followed for 6 months. Primary end points focus on the the removal of protein-bound solutes, inflammation and nutritional state. In addition, ESAs doses and hemoglobin levels will be assessed and compared between treatment groups.