Effect of the super-flux cellulose triacetate dialyser membrane on the removal of non-protein-bound and protein-bound uraemic solutes

Background. Uraemic solutes accumulate in haemodialysis (HD) patients and interfere with physiological functions. Low-flux (LF) HD does not efficiently remove all uraemic compounds. We investigated whether large pore super-flux (SF) cellulose triacetate membranes (CTA) result in a better removal of uraemic solutes. Methods. Eleven patients were dialysed consecutively with LF-CTA and SF-CTA during 3 weeks. Urea (UR), creatinine (CR), uric acid (UA), 3-carboxy-4methyl-5-propyl-2-furanpropionic acid (CMPF), indole-3-acetic acid (IAA), indoxyl sulfate (IS), hippuric acid (HA), pentosidine (PENT), low-molecular weight (MW) AGEs (AGEs) and albumin were determined in pre-HD, post-HD blood and in dialysate. Reduction rate (RR), dialytic clearance and mass transfer-area coefficient (KoA) were calculated. Results. SF-HD resulted in a higher RR than LF-HD for IS and AGEs. Urea RR correlated with HA (r = 0.59), IS (r = 0.68) and IAA (r = 0.67), (P < 0.05) for SF. Dialytic clearance ranged from 20 +/- 5 to 179 +/- 20ml/min for LF and from 24 +/- 6 to 191 +/- 24ml/min for SF; being higher with SF for UA, HA, IS and IAA (SF vs LF, P < 0.05). KoA was higher for most compounds with SF-HD. Albumin loss per SF session was 3.4 +/- 1.3 g. The retrieved amount of uraemic solutes in dialysate with LF and SF was comparable. Conclusions. In conventional HD, SF-CTA was superior to LF-CTA for removal of most protein-bound compounds, especially IS. Reduction rate, dialytic clearance and KoA were higher with SF. The SF-CTA membrane is albumin-leaking; however, this property could not completely explain the amount of retrieved protein-bound compounds in dialysate.