The general objective assigned to the European DIALysis (EUDIAL) Working Group by the European Renal Association – European Dialysis and Transplant Association (ERA-EDTA) was to enhance the quality of dialysis therapies in Europe in the broadest possible sense. Given the increasing interest in convective therapies, the Working Group has started by focusing on hemodiafiltration (HDF) therapies. A EUDIAL consensus conference was held in Paris on 13 October 2011 to discuss definitions, safety standards, clinical outcome and educational issues. Recently, the first report of the EUDIAL group was published, revisiting the definition, dose quantification, and safety of HDF. Since the meeting in Paris, new evidence has become available regarding the clinical benefits of HDF. This is the second report of the expert group in which the relation between HDF and clinical outcomes is systematically reviewed and analyzed, with emphasis on the relation between achieved convection volume and treatment effect.

In post-dilution online haemodiafiltration (ol-HDF), a relationship has been demonstrated between the magnitude of the convection volume and survival. However, to achieve high convection volumes (>22 L per session) detailed notion of its determining factors is highly desirable. This manuscript summarizes practical problems and pitfalls that were encountered during the quest for high convection volumes. Specifically, it addresses issues such as type of vascular access, needles, blood flow rate, recirculation, filtration fraction, anticoagulation and dialysers. Finally, five of the main HDF systems in Europe are briefly described as far as HDF prescription and optimization of the convection volume is concerned.

Background/Aims: Sub-analyses of three large trials showed that hemodiafiltration (HDF) patients who achieved the highest convection volumes had the lowest mortality risk. The aims of this study were (1) to identify determinants of convection volume and (2) to assess whether differences exist between patients achieving high and low volumes. Methods: HDF patients from the CONvective TRAnsport STudy (CONTRAST) with a complete dataset at 6 months (314 out of a total of 358) were included in this post hoc analysis. Determinants of convection volume were identified by regression analysis. Results: Treatment time, blood flow rate, dialysis vintage, serum albumin and hematocrit were independently related. Neither vascular access nor dialyzer characteristics showed any relation with convection volume. Except for some variation in body size, patient characteristics did not differ across tertiles of convection volume. Conclusion: Treatment time and blood flow rate are major determinants of convection volume. Hence, its magnitude depends on center policy rather than individualized patient prescription.

Background and objective Increased left ventricular mass (LVM), low ventricular ejection fraction (EF), and high pulse-wave velocity (PWV) relate to overall and cardiovascular mortality in patients with ESRD. The aim of this study was to determine the effect of online hemodiafiltration (HDF) versus low-flux hemodialysis (HD) on LVM, EF, and PWV.Design, setting, participants, & measurements Echocardiography was used to assess LVM and EF in 342 patients in the CONvective TRAnsport STudy followed for up to 4 years. PWV was measured in 189 patients for up to 3 years. Effect of HDF versus HD on LVM, EF, and PWV was evaluated using linear mixed models.Results Patients had a mean age of 63 years, and 61% were male. At baseline, median LVM was 227 g (interquartile range [IQR], 183-279 g), and median EF was 65% (IQR, 55%-72%). Median PWV was 9.8 m/s (IQR, 7.5-12.0 m/s). There was no significant difference between the HDF and HD treatment groups in rate of change in LVM (HDF: change, 20.9 g/yr [95% confidence interval (95% CI), 28.9 to 7.7 g]; HD: change, 12.5 g/yr [95% CI, 23.0 to 27.5 g]; P for difference=0. Conclusions Treatment with online HDF did not affect changes in LVM, EF, or PWV over time compared with HD.

Background and ObjectivesLeft ventricular mass (LVM) is known to be related to overall and cardiovascular mortality in end stage kidney disease (ESKD) patients. The aims of the present study are 1) to determine whether LVM is associated with mortality and various cardiovascular events and 2) to identify determinants of LVM including biomarkers of inflammation and fibrosis.Design, Setting, Participants, & MeasurementsAnalysis was performed with data of 327 ESKD patients, a subset from the CONvective TRAnsport STudy (CONTRAST). Echocardiography was performed at baseline. Cox regression analysis was used to assess the relation of LVM tertiles with clinical events. Multivariable linear regression models were used to identify factors associated with LVM.ResultsMedian age was 65 (IQR: 54–73) years, 203 (61%) were male and median LVM was 227 (IQR: 183–279) grams. The risk of all-cause mortality (hazard ratio (HR) = 1.73, 95% CI: 1.11–2.99), cardiovascular death (HR = 3.66, 95% CI: 1.35–10.05) and sudden death (HR = 13.06; 95% CI: 6.60–107) was increased in the highest tertile (>260grams) of LVM. In the multivariable analysis positive relations with LVM were found for male gender (B = 38.8±10.3), residual renal function (B = 17.9±8.0), phosphate binder therapy (B = 16.9±8.5), and an inverse relation for a previous kidney transplantation (B = −41.1±7.6) and albumin (B = −2.9±1.1). Interleukin-6 (Il-6), high-sensitivity C-reactive protein (hsCRP), hepcidin-25 and connective tissue growth factor (CTGF) were not related to LVM.ConclusionWe confirm the relation between a high LVM and outcome and expand the evidence for increased risk of sudden death. No relationship was found between LVM and markers of inflammation and fibrosis.Trial RegistrationControlled-Trials.com ISRCTN38365125

Increasing evidence suggests that treatment with online post-dilution haemodiafiltration (HDF) improves clinical outcome in patients with end-stage kidney disease, if compared with haemodialysis (HD). Although the primary analyses of three large randomized controlled trials (RCTs) showed inconclusive results, post hoc analyses of these and previous observational studies comparing online post-dilution HDF with HD showed that the risk of overall and cardiovascular mortality is lowest in patients who are treated with high-volume HDF. As such, the magnitude of the convection volume seems crucial and can be considered as the ‘dose’ of HDF. In this narrative review, the relevance of high convection volume in online post-dilution HDF is discussed. In addition, we briefly touch upon some safety and cost issues.

The CONvective TRAnsport STudy (CONTRAST) is a large randomized controlled trial which compared on-line postdilution hemodiafiltration and low-flux hemodialysis in terms of mortality and cardiovascular events. This review summarizes and discusses currently available knowledge acquired by CONTRAST, including the main outcome, comparisons of hemodiafiltration to hemodialysis as well as studies performed in subgroups of CONTRAST.

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