Hemodiafiltration: Technical and Medical Insights

Abstract

Despite the significant medical and technical improvements in the field of dialytic renal replacement modalities, morbidity and mortality are excessively high among patients with end-stage kidney disease, and most interventional studies yielded disappointing results. Hemodiafiltration, a dialysis method that was implemented in clinics many years ago and that combines the two main principles of hemodialysis and hemofiltration—diffusion and convection—has had a positive impact on mortality rates, especially when delivered in a high-volume mode as a surrogate for a high convective dose. The achievement of high substitution volumes during dialysis treatments does not only depend on patient characteristics but also on the dialyzer (membrane) and the adequately equipped hemodiafiltration machine. The present review article summarizes the technical aspects of online hemodiafiltration and discusses present and ongoing clinical studies with regards to hard clinical and patient-reported outcomes.

Advances in Human-Centered Care to Address Contemporary Unmet Needs in Chronic Dialysis

“… 105 Despite these promising findings, concerns about participant attrition during follow-up in these trails may have hindered widespread HDF adoption outside of Europe and Japan. 106 This is despite an individual-participant meta-analysis of four randomised controlled trials showing a reduction in all-cause mortality and cardiovascular mortality with high-dose HDF compared to HD. 107 Recently, the landmark CONVINCE study, a randomised-controlled trial of 1360 patients randomised to high-dose HDF and HD, demonstrated an absolute risk reduction in mortality of 4.6% (HR 0.77, 95% CI: 0.65–0.93).…”

On the total albumin losses during haemocatharsis

“…This deposit layer, whose significance has been recognised long ago [ 13 , 17 ], is often referred to as “secondary membrane” or fouling/’gel’ layer [ 17 ]. As noted below, the physico-chemical protein/polymeric-material interactions, also significantly affect albumin leaking to dialysate, due to the reduced membrane porosity and permeability caused by the adsorbed/deposited proteins [ 3 , 15 , 18 ]. In addition, it should be stressed that protein adsorption and fouling-layer/gel formation, is related to other complicated phenomena, including albumin unfolding/denaturation and ‘competitive adsorption’ among the most abundant proteins (i.e.…”

“…Many studies (e.g. [ 1 – 3 ]), show that, in particular OL-post-HDF (online, post-dilution haemodiafiltration), involving large transmembrane/ultrafiltration rate (and the concomitant large substitution volume), is quite beneficial leading to reduced mortality [ 1 , 3 ]. However, there is concern that, under such conditions (involving relatively high-permeability membranes), excessive albumin losses may occur, which are possibly associated with hypoalbuminemia, at least for some ESRD-patient categories [ 4 ].…”

Hydrophilic Modification of Dialysis Membranes Sustains Middle Molecule Removal and Filtration Characteristics

“…To achieve the treatment targets that were shown during the CONVINCE trial to impact patient outcomes, the dialysis session must be performed with a dialyzer that enables high ultrafiltration volumes and high middle molecule removal [11]. Dialyzer performance is mainly determined by the dialyzer membrane, which may differ in material composition, geometry, or structure, including the pore size and properties of the blood-facing surface [12][13][14][15][16][17][18][19].…”

“…The novel FX CorAL dialyzer contains such a hydrophilic membrane with increased PVP content on the blood-side surface and was shown in clinical and experimental studies to induce lower protein adsorption than other commonly used dialyzers in clinical practice [12,[36][37][38]. Moreover, the FX CorAL dialyzer was previously compared to other polysulfone-, polyethersulfone-, and cellulose-based dialyzers with regard to performance and hemocompatibility [11,12,19,[36][37][38][39][40][41]. Experimental studies showed a strong correlation between the low protein adsorption by the FX CorAL and the good hemocompatibility profile as well as low sieving coefficient changes over time [19,38].…”