A microdomain-structured synthetic high-flux hollow-fiber membrane for renal replacement therapy

A prospective crossover clinical study evaluated solute removal and biocompatibility of a tailored, hydrophobic-hydrophilic microdomain structure produced from a blend of polyamide, polyarylethersulfone, and polyvinylpyrrolidone (Polyflux) compared with Fresenius Polysulfone in dialyzers of similar surface area. The clearance of small molecules (urea, creatinine, and phosphate) for both membranes was comparable. Plasma levels of beta2 microglobulin were reduced at the end of treatment with both membranes (49.8% of pretreatment values for Polyflux; 45.9%, Fresenius Polysulfone) and was associated with the recovery of 207 +/- 84 mg of beta2 microglobulin from the dialyzing fluid for Polyflux compared with 147 +/- 29 for Fresenius Polysulfone (p = 0.12). The dialyzing fluid also contained 7,758 mg of protein when using Polyflux compared with 7,793 mg using Fresenius Polysulfone (standard error of difference for any pair was 511 mg). No albumin was present in the dialysis fluid for either membrane. Neutropenia, platelet adhesion to the membrane, and complement activation characterized by C3a, C5a, and SC5b-9 generation were slight and independent of membrane type. Membrane thrombus generating potential measured by thrombin:antithrombin III were also similar. These results indicate that the tailored, hydrophobic-hydrophilic microdomain structure of the membrane results in a favorable biocompatibility profile and clinically acceptable solute removal similar to the widely used Fresenius Polysulfone membrane.