Online Hemodiafiltration Versus Acetate‐Free Biofiltration: A Prospective Crossover Study

Abstract

Online hemodiafiltration (online HDF) and acetate-free biofiltration (AFB) are 2 innovative renal replacement therapies. Convincing evidence has shown that both techniques are superior to conventional hemodialysis in many aspects. The aim of the present investigation was to compare online HDF and AFB in 12 stable maintenance hemodialysis patients in a prospective, randomized crossover trial. Twelve stable dialysis patients, age 49.7 +/- 11.3 years and on dialysis for 83.5 +/- 76.7 months, were treated prospectively and randomly by either AFB, predilution HDF (pre-HDF), or postdilution HDF (post-HDF) for a total of 36 weeks using exclusively F60S high-flux dialyzers. Routine blood biochemical tests, bone metabolism parameters, and clearance for both small and larger molecular weight substances were measured at defined intervals. During the trial period inter- and intradialysis symptoms, e.g., hypotensive episodes and intradialysis arterial blood gas analyses, were recorded. Both online HDF and AFB were well accepted by the overwhelming majority of patients and also by the dialysis staff. Pretreatment sodium, total and ionized calcium, chloride, bicarbonate, and urea did not differ within or between the 3 treatment groups. Potassium increased slightly in HDF patients while phosphate and beta2-microglobulin (beta2-M) decreased in all groups. After dialysis, AFB patients exhibited a significantly higher bicarbonate concentration and lower potassium level when identical potassium concentrations in dialysate were used. Patients receiving AFB manifested less intradialysis partial pressure of oxygen drop and partial pressure of carbon dioxide rise than those on HDF treatments. HDF treatments could afford higher single-pool and double-pool Kt/V, higher effective urea and beta2M clearance, and lower total interdialysis symptom scores than the AFB treatment method. While bone metabolism parameters did not differ between the 3 dialysis modalities, some parameters such as deoxypyridinoline in HDF and osteocalcin, pyridinoline, and deoxypyridinoline in AFB deteriorated at the end of the crossover study. Aluminum concentration decreased progressively to about one-third of prestudy values at the end of the study with all 3 treatments. AFB was associated with a lower predialysis mean arterial pressure (MAP), a smaller drop in MAP during treatment, and similar hypotension episodes compared with the 2 HDF treatments. Albumin concentration showed a trend to decrease during the first 2 months of the trial period followed by a slight increase thereafter but still significantly lower than initial value at the end of crossover. Both online HDF and AFB share most of the features of optimal renal replacement therapy. Online HDF is superior to AFB in such aspects as increased delivered dialysis dose both for small and larger molecular weight toxins and less interdialysis symptoms. On the other hand, AFB is associated with a smaller effect on arterial blood gas values and improved intradialysis hemodynamic tolerance. Some dialysis-related s...

Influence of Online Hemodiafiltration on Hemoglobin Level, ESA-Dosage and Serum Albumin – A Retrospective, Multicenter Analysis

“…In low flux dialysis protein removal only occurs with adsorptive membranes (PMMA, polyacrilonitrile) with decreasing dialysis efficacy for water soluble toxins (Parzer et al, 1993). This removal of albumin can be compensated after a time of about 12 weeks in the absence of relevant inflammation (Ding et al, 2002;Kaysen et al, 1997). In chronic ambulant peritoneal dialysis protein losses are in-between 6 to 10 g/d and albumin losses up to 5 g/d over the peritoneal membrane (Kaysen et al, 1984).…”

“…It is shown that in olHDF the ESA dosage needed to reach the hemoglobin goal is reduced (Vaslaki et al, 2006;Bonforte et al, 2002;Eiselt et al, 2000). The efficacy of dialysis measured by single pool Kt/V could be improved (Ahrenholz et al, 1997;Ding et al, 2002). There is evidence of longer survival of patients treated by olHDF versus hemodialysis (HD) independently of dialysis dosage (Canaud et al, 2008;Panicchi et al, 2008).…”

Controversies and Issues in Hemodiafiltration Therapy

“…In a prospective long-term cross-over study comparing on-line 180 ml/min pre-dilution and 60-80 ml/min post-dilution hemodiafiltration to acetate-free biofiltration with infusion of 20-30 ml/min isotonic bicarbonate solution, the differences in biochemistry parameters among the three modalities of treatment were not remarkable and the reduction rate of ß 2 -microglobulin is not statistically different [29]. These data open the debate of the optimal volume of ultrafiltration and substitution fluid.…”

Increasing Haemodialytic Clearances as Residual Renal Function Declines: An Incremental Approach

“…Although most dialysates now contain 3-5 mEq/L of acetate, this has been suggested to have a clinical effect when infused as part of a large volume replacement fluid [59]. Implementation of acetate-free HDF potentially reduces the risk of intra-dialytic hypotension [60] after the long inter-dialytic interval, although this technique typically leads to a greater positive sodium balance, and has not been shown to provide greater cardiovascular stability compared to high-volume online HDF [61]. …”