Effect of membrane permeability on inflammation and arterial stiffness: a randomized trial.

BACKGROUND AND OBJECTIVES Both larger molecule removal and dialyzer biocompatibility have been implicated in the high-flux hemodialysis (HD)-associated favorable outcome. In an attempt to delineate the effect of membrane permeability, we performed a randomized, crossover study to compare the inflammatory biomarkers, lipid profile, and aortic pulse wave velocity (PWV) of two dialyzers that are composed of identical membranes but with different flux characteristics. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Stable patients who had anuria and were on low-flux polysulfone membrane were randomly allocated either to HD with high-flux polyamide membrane (group A; 22 patients) or to HD with low-flux polyamide membrane (group B; 24 patients) for 24 weeks, then they were started on 24 weeks of the alternative HD treatment. Apart from the dialyzer, the dialysis prescription remained unchanged. RESULTS Nineteen patients from group A and 23 patients from group B completed the study. Predialysis beta(2)-microglobulin levels decreased significantly when using the high-flux polyamide membrane. No difference between membranes was observed for serum albumin, high-sensitivity C-reactive protein, fibrinogen, IL-6, triglycerides, HDL cholesterol, LDL cholesterol, and lipoprotein(a) during the study. A significant increase in aortic PWV, a marker of aortic stiffness, was noted after patients switched from high-flux to low-flux polyamide membranes. Similarly, the rate of change in aortic PWV was significantly decreased with the use of the high-flux polyamide membrane. CONCLUSIONS Our findings suggest that dialysis with polyamide membranes with different flux characteristics did not modify the inflammatory indices and lipid profile in stable HD patients; however, a seemingly beneficial effect on aortic stiffness was noted for patients who were maintained on high-flux polyamide membrane.