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A significant and increasing number of chronic kidney disease (CKD) patients are treated with online hemodiafiltration (OL-HDF), even in the absence of more conclusive survival data. OL-HDF affords several clinical benefits including control of anemia of CKD, a common affliction in dialysis patients. In efforts to understand the underlying mechanisms that contribute to the purported benefits of OL-HDF, we examined the potential role and impact of OL-HDF on key stages of anemia and its correction: erythropoiesis of bone marrow, circulating erythrocytes and on anemia therapy. We review evidence that indicates OL-HDF may modulate key processes of anemia and its therapy, including underlying conditions and responses of uremic toxicity and inflammation that aggravate anemia. Our assessment indicates that OL-HDF favorably impacts anemia by not only eliminating putative uremic inhibitors that suppress erythropoiesis, reducing red cell destruction and increasing iron availability, but also by mechanisms restricting underlying inflammation and endothelial dysfunction that are crucial to both CKD and anemia., (Copyright © 2011 S. Karger AG, Basel.)

The majority of patients with chronic kidney disease are currently treated with dialyzers containing synthetic membranes. Of all the dialysis membranes made from these polymers, 93% are from the parent polyarylsulfone family of which 71% are from polysulfone (PSu) and 22% from polyethersulfone. The preference of nephrologists for PSu dialyzers signifies their versatility in terms of meeting the solute and fluid removal demands for all treatment modalities (low-and high-flux dialysis, online hemodiafiltration, hemofiltration). The unprecedented success and widespread usage of PSu membranes is attributed, in addition to efficient removal of a broad spectrum of uremic toxins, to other criteria required of modern dialysis therapies. Namely, effective endotoxin retention capacity, pronounced intrinsic biocompatibility and low cytotoxicity are factors which all contribute to minimal adverse clinical sequelae. Furthermore, PSu by virtue of its high thermal stability can be sterilized with steam, the preferred mode of sterilization as it does not have the disadvantages associated with other sterilization methods. However, there are significant differences between membranes made from PSu due to differences in membrane polymer recipes and manufacturing technologies. Although PSu may be the main constituent, these membranes are blended with other polymers, e.g. hydrophilizing agents, such as polyvinylpyrrolidone to give each membrane its characteristic profile. The relative amounts of the two (or more) co-polymers as well as the spinning conditions provide a fingerprint of each membrane in terms of solute separation characteristics, biocompatibility, cytotoxicity or endotoxin retention capabilities. PSu membrane-based dialyzers thus fulfill the crucial therapy requirements of current treatment modalities to varying extents. Thereby, different effects towards patient outcomes and treatment safety are achieved., (Copyright © 2011 S. Karger AG, Basel.)

The aim of the study was to assess the biocompatibility profile of a newly developed high-flux polysulfone dialyzer type (FX-class dialyzer). The new class of dialyzers incorporates a number of novel design features (including a new membrane) that have been developed specifically in order to enhance the removal of small- and middle-size molecules. The new FX dialyzer series was compared with the classical routinely used high-flux polysulfone F series of dialyzers. In an open prospective, randomized, crossover clinical study, concentrations of the C5a complement component, and leukocyte count in blood and various thrombogenicity parameters were evaluated before, and at 15 and 60 min of hemodialysis at both dialyzer inlet and outlet in 9 long-term hemodialysis patients using the FX60S dialyzers and, after crossover, the classical F60S, while in another 9 patients, the evaluation was made with the dialyzers used in reverse order. The comparison of dialyzers based on evaluation of the group including all procedures with the FX60S and the group including procedures with the F60S did not reveal significant differences in platelet count, activated partial thromboplastin times, plasma heparin levels, platelet factor-4, D-dimer, C5a, and leukocyte count at any point of the collecting period. Both dialyzer types showed a significant increase in the plasma levels of the thrombin-antithrombin III complexes; however, the measured levels were only slightly elevated compared with the upper end of the normal range. Biocompatibility parameters reflecting the behavior of platelets, fibrinolysis, complement activation, and leukopenia do not differ during dialysis with either the FX60S or the F60S despite their large differences in design and geometry features. Although coagulation activation, as evaluated by one of the parameters used, was slightly higher with the FX60S, it was still within the range seen with other highly biocompatible dialyzers and therefore is not indicative of any appreciable activation of the coagulation system. Thus, the incorporation of various performance-enhancing design features into the new FX class of dialyzers does not result in a deterioration of their biocompatibility profile, which is comparable to that of the classical F series of dialyzers.

There is widespread recognition that the poor survival rates of dialysis patients, attributed predominantly to cardiovascular disease, need to be addressed and improved. In this paper, we relate diverse aspects of modern dialysis technology with factors that are considered to contribute towards increased mortality and morbidity in the dialysis population. Firstly, we assess the overall cardiovascular burden of the dialysis patient: it is the sum of uraemia-related risk factors (URRF), traditional risk factors and dialysis-therapy-related factors. Secondly, we describe how key components of the dialysis procedure may be directly related to the more common URRF: the dialyser and the membrane, microbiological quality of water and dialysate, treatment modality and online monitory equipment. The judicious selection and application of these components may collectively help improve patient outcomes in hemodialysis therapy.