Multipotentials of new asymmetric cellulose triacetate membrane for on-line hemodiafiltration both in postdilution and predilution

Abstract

Background: On-line hemodiafiltration (OL-HDF) has been generally provided mainly by the postdilution method in Europe and the rest of the world; however, in Japan, it has been provided mostly by the predilution method in order to ameliorate dialysis-related symptoms of dialysis patients by removing larger low molecular weight proteins. This study aimed to elucidate the removal properties of a newly launched asymmetric triacetate (ATA) membrane in OL-HDF both in the postdilution and predilution comparison with other synthetic polymer membranes. Methods: Six patients treated by OL-HDF at the Kawashima Hospital Group were randomly chosen for each membrane study. The removal properties of low molecular weight proteins were evaluated by β 2-microglobulin (β 2-MG), α 1microglobulin (α 1-MG), albumin leakage, selective removal index of α 1-MG for albumin, and transmembrane pressure for each treatment group. Two types of ATA membrane were evaluated in the study: FIX-S with mild protein permeability and FIX-U with higher protein permeability in the comparisons with other three types of synthetic polymer membranes. Results: The removal rate of β 2-MG showed almost no significant differences between the postdilution and predilution methods in most membrane groups at around 75-80% without relations to the membrane material and the substitution volume. The removal rates of α 1-MG were markedly different depending on the dilution method of HDF, the membranes, and the substitution volume. Generally, the removal rates of α 1-MG were better in the postdilution than the predilution but the selective removals of α 1-MG were better in the predilution. The high volume OL-HDF had the risk of excessive albumin leakage in a certain membrane choice. In the FIX series, the removal rates of α 1-MG were sufficient both in the postdilution and predilution with the increase of the substitution volume with suppressing the albumin leakage during the dialysis session. Especially, FIX-U showed higher removal of α 1-MG with suppressing the albumin leakage. Conclusions: The newly launched ATA membrane could remove α 1-MG, selectively suppressing the excessive albumin leakage and increasing the substitution volume safely even in high-volume postdilution.

Removal performance of pre- and post-dilution online hemodiafiltration using identical hemodiafilters in the same patients

“…The removal performance of the middle molecules increases as the substitution volume increases in the same dilution mode, and comparing the dilution modes, post-OHDF is superior to pre-OHDF. This result resonates with that of previous studies [20].…”

“…Therefore, β 2 -MG, with a molecular weight of 11,800, was thought to be removed mainly by diffusion rather than by filtration. This is consistent with the findings of previous reports that compared the removal performance of pre-and post-OHDF [5,20]. As β 2 -MG is removed mainly by diffusion, it would be insufficient to attribute the improvement in mortality resulting from OHDF to β 2 -MG removal only.…”

“…To assess the selectivity of the α 1 -MG removal for albumin leakage, the selective removal index of α 1 -MG (SRIA) was calculated [20]. The SRIA was calculated as the amount of α 1 -MG removed divided by the amount of albumin leakage in a single session using the following formula:…”

“…*p < 0.05 compared to the minimum substitution volume of the same dilution method **p < 0.01 compared to the minimum substitution volume of the same dilution method1 All values are indicated, excluding that of one patient whose sample could not be measured (n = 7)2 Selective removal index of alpha-1-microglobulin[20] …”

Effects of on-line hemodiafiltration regimens and dialysate composition on serum concentrations of magnesium and calcium ions

“…Furthermore, the albumin leakage in the membrane we employed was well defined. Given that the membrane used in this study did not cause excessive transmembrane pressure or significant albumin leakage [18], our results indicated that post-dilution OL-HDF does not significantly impact the concentration of ionized magnesium and calcium when albumin leakage is limited to approximately 5 g/session.…”