SP416LARGE MIDDLE-MOLECULE REMOVAL DURING HEMODIALYSIS USING A NOVEL MEDIUM CUTOFF DIALYZER

Abstract

Introduction and Aims: In vitro data suggest that medium cutoff (MCO) dialyzers allow for a higher removal of medium‐sized molecules, while limiting albumin loss. The present study examined for the first time the effect of MCO dialyzers in comparison to a lastgeneration high‐flux dialyzer on large middle molecule removal during hemodialysis. Methods: During 4 consecutive mid‐week dialysis sessions, 19 ESRD patients (mean age 55.4 +/‐ 13.44 years; 7 females, 12 males; mean dialysis vintage 4.9 +/‐ 4.65 years) were treated with each of three MCO‐HD dialyzer prototypes (MCO AA, BB, or CC [Gambro Dialysatoren GmbH, Germany]) and a last‐generation high‐flux dialyzer (Fx CorDiax 80 [Fresenius Medical Care, Bad Homburg, Germany] in random order. During treatments (blood flow rate 312 +/‐ 24 mL/min), arterial and venous blood samples and spent dialysate were collected to determine removal of lambda and kappa free Ig light chain (FLC), alpha1‐ microglobulin, complement factor D, myoglobin, beta2‐microglobulin and small solutes. The primary endpoint was overall clearance of lambdaFLC. The secondary outcomes were the removal of other medium‐sized and small molecules and the safety of these prototype MCO dialyzers. Comparative analyses were conducted with a mixed model appropriate for a cross‐over design. Data are given as LSmean +/‐ SE. Results: HD treatment with the MCO dialyzer prototypes provided significantly higher overall clearance of lambdaFLC (MCO AA, BB, and CC vs. FX CorDiax 80; 8.5+/‐0.54, 11.3+/‐0.51, and 15.0+/‐0.53 vs. 3.6+/‐0.51 mL/min, respectively; p<0.001 for each) and of kappaFLC (26.2 +/‐1.24, 31.8+/‐1.17, and 37.3+/‐1.24 vs. 3.3+/‐1.17 mL/min, respectively; p<0.001 for each) compared to HD treatment with last generation high‐flux dialyzer. Accordingly, reduction ratios of lambdaFLC and kappaFLC by 4 hours of dialysis were also significantly higher with each MCO dialyzer compared to the high‐flux dialyzer, respectively (p<0.001 for each). Also, removal of other medium‐sized solutes, (alpha1‐microglobulin, complement factor D, myoglobin and beta2‐microglobulin) was significantly greater (p<0.001), as was overall clearance of phosphate (p<0.001) and of urea (p<0.05). Total mass of albumin removed with theMCO AA, BB, and CC dialyzers was significantly larger compared to the high‐flux dialyzer (medians [range]: 2.9 g [1.5‐3.9], 4.8 g [2.2‐6.7], and 7.3 g [1.9‐9.7] vs. <0.3 g [<0.3‐<0.3], respectively). Conclusions: The MCO dialyzer prototypes studied achieved significantly higher removal of all medium‐sized solutes studied compared to a last‐generation high‐flux dialyzer with moderate albumin removal and are safe to use during routine HD treatments. Potentially improved outcomes due to better middle molecule removal in ESRD patients during HD should be assessed in prospective studies.