Enhanced Functional Performance Characteristics of a New Polysulfone Membrane for High-Flux Hemodialysis

Abstract

Elimination of uremic solutes with molecular weights up to 60 kD, without significant loss of albumin is an important therapeutic goal to optimize outcomes in chronic hemodialysis patients. To characterize a newly developed polysulfone dialyzer (APS-650) a comparative analysis was performed with a highly advanced polysulfone dialyzer (F-60S) including 22 stable chronic hemodialysis patients. Diffusive clearances were determined, and albumin loss was calculated. The elimination profile of uremic solutes up to 32.0 kD was assessed in vivo by sieving coefficients, clearances, and reduction ratios of β₂-microglobulin (11.8 kD), myoglobin (17.2 kD), prolactin (23.0 kD), and α₁-microglobulin (32.0 kD). Hemocompatibility was tested in serial measurements of total white blood cell count, platelet count, C3a, and neutrophil elastase. No significant albumin loss was detected. Significantly higher sieving coefficients, clearances, and reduction ratios for proteins with molecular weight up to 32.0 kD were demonstrated with the newly developed polysulfone membrane. Both polysulfone membranes were equal concerning hemocompatibility parameters. The APS-650 dialyzer allowed optimized hemodialysis treatment with respect to clearance of medium-sized uraemic solutes by high-flux dialysis.

In vivo Removal of High- and Low-Molecular-Weight Compounds in Hemodiafiltration with On-Line Regeneration of Ultrafiltrate

“…We demonstrate that with HFR on-line, the loss of RBP and α 1 -microglobulin and proteins with higher molecular weight was negligible. Despite the absence of formal comparison with the other hemodialysis techniques, data from literature confirms that with this new two-step integrated sorbent system, the solute removal index, over a wide molecular-weight spectrum is adequate, showing either superiority to conventional hemodialysis and at least similar results with hemodiafiltration techniques [16,23,24,25,26,27,28]. Interestingly, in our study we were unable to demonstrate any loss of pre-albumin and albumin in the regenerated ultrafiltrate.…”

Performance of polysulfone membrane dialyzers and dialysate flow pattern

“…The APS-S series shows significantly better sieving coefficients, improved clearance, and small percent reduction values for proteins with a molecular weight of up to 32 000 in comparison with standard polysulfone dialyzers, without any greater loss of albumin. 9 This type of dialyzer was also reported to be highly efficient at preventing the transfer of cytokineinducing bacterial products from contaminated dialysis fluid into the patient's blood. 10 In the present study, the clearance of low-molecular-weight urea nitrogen and the permeability for high-molecular-weight albumin were both significantly greater with the TS-UL than with the APS-S.…”

Intradialytic serum protein concentrations differ between nightly nocturnal and conventional haemodialysis

“…Although six NHD patients were converted to high flux membranes prior to the second set of blood collections, the proteins studied were of sufficient molecular weight to render transmembrane protein losses negligible and no higher than what might occur with low flux membranes 12 …”

“…Serum proteins are confined to the intravascular space, their high molecular weights preventing them from traversing capillary walls 11 and dialyser membranes. 12 Changes in protein concentration occurring during HD are therefore primarily due to fluxes in the intravascular fluid volume. An intradialytic increase in protein concentration can thus be considered a surrogate marker for intravascular volume contraction.…”