A new generation of cellulose triacetate suitable for online haemodiafiltration

Online haemodiafiltration (OL-HDF) is currently the most effective dialysis technique that also improves survival. To date, high permeability membranes with low albumin loss, such as polysulfone, polyamide and polyacrylonitrile membranes have been the most widely used. However, the initially restricted use of cellulose triacetate (CTA) membranes in OL-HDF has expanded. The aim of the study was to ascertain whether the latest generation asymmetric CTA membranes are more effective in obtaining high convective transport.

A total of 16 patients (10 males and 6 females) undergoing OL-HDF were studied. Each patient underwent 4 different sessions, with haemodialysis or OL-HDF, and/or with CTA or asymmetric CTA 1.9 m² membranes. Each session was assigned in a randomised order. Serum levels of urea, creatinine, β₂-microglobulin, myoglobin, prolactin, α₁-microglobulin, α₁-acid glycoprotein and albumin where measured at the beginning and end of each session to obtain the reduction rate. The loss of solutes and albumin was quantified from the dialysate.

A significantly greater replacement volume in OL-HDF (32.1±3.1 vs. 19.7±4.5 l, P<.001) was obtained by using asymmetrical CTA membranes compared to conventional CTA membranes. Regarding uraemic toxin removal, both membranes obtained similar results for small molecules, whereas asymmetric CTA membranes achieved better results for large molecules, increasing the reduction ratio by 29% for β₂-microglobulin, 27.7% for myoglobin, 19.5% for prolactin, 49% for α₁-microglobulin and double for α₁-acid glycoprotein (P<0.001 in all situations). The loss of albumin was less than 2g for all treatment sessions.

Latest-generation asymmetric CTA have proven to be effective in attaining OL-HDF objectives without increased albumin loss.