Effects of different membranes and dialysis technologies on patient treatment tolerance and nutritional parameters

Abstract

There is increasing evidence that the biochemical and cellular phenomena induced by blood/ membrane/dialysate interactions contribute to dialysis-related intradialytic and long-term complications. However, there is a lack of large, prospective, randomized trials comparing biocompatible and bioincompatible membranes, and convective and diffusive treatment modalities. The primary aim of this prospective, randomized trial was to evaluate whether the use of polysulfone membrane with bicarbonate dialysate offers any advantage (in terms of treatment tolerance, nutritional parameters and pre-treatment beta-microglobulin levels) over a traditional membrane (Cuprophan). A secondary aim was to assess whether the use of more sophisticated methods consisting of a biocompatible synthetic membrane with different hydraulic permeability at different ultrafiltration rate (high-flux hemodialysis and hemodiafiltration) offers any further advantages. Seventy-one Centers were involved and stratified according to the availability of only the first two or all four of the following techniques: Cuprophan hemodialysis (Cu-HD), low-flux polysulfone hemodialysis (LfPS-HD), high-flux polysulfone high-flux hemodialysis (HfPS-HD), and high-flux polysulfone hemodiafiltration (HfPS-HDF). The 380 eligible patients were randomized to one of the two or four treatments (132 to Cu-HD, 147 to LfPS-HD, 51 to HfPS-HD and 50 to HfPS-HDF). The follow-up was 24 months. No statistical difference was observed in the algebraic sum of the end points between bicarbonate dialysis with Cuprophan or with low-flux polysulfone, or among the four dialysis methods under evaluation. There was a significant decrease in pre-dialysis plasma beta 2-microglobulin levels in high-flux dialysis of 9.04 +/- 10.46 mg/liter (23%) and in hemodiafiltration of 6.35 +/- 12.28 mg/liter (16%), both using high-flux polysulfone membrane in comparison with Cuprophan and low-flux polysulfone membranes (P = 0.032). The significant decrease in pre-dialysis plasma beta 2-microglobulin levels could have a clinical impact when one considers that beta 2-microglobulin accumulation and amyloidosis are important long-term dialysis-related complications.

Role of Residual Kidney Function and Convective Volume on Change in β2-Microglobulin Levels in Hemodiafiltration Patients

“…However, in a preliminary analysis of CON-TRAST data, ␤2M levels at 12 mo seemed to be similar to those at 6 mo (31). Other studies indicate that a steady state is reached after 3 to 12 mo (10,12,13). Furthermore, only predialysis ␤2M levels were measured, so ␤2M clearance could not be calculated.…”

“…In addition, it has been shown that removal of ␤2M is further increased with online hemodiafiltration (HDF) by using excess ultrafiltration to provide increased convective transport. Actually, lower predialysis ␤2M levels have been reported after 3 to 12 mo treatment with HDF, as compared with low-flux or high-flux HD (10)(11)(12)(13)(14)(15). It has been proposed that the improved survival of HDF patients, as reported in few observational studies (16)(17)(18), can be partly attributed to increased removal of ␤2M and other MMW uremic toxins by convective transport.…”

Technical Breakthroughs in the Wearable Artificial Kidney (WAK)

“…We name this "pulsatile push-pull internal hemodiafiltration." An increase in convective mass transfer of middle molecular weight molecules in hemodiafiltration may be the preferable way of treating ESRD (28,29).…”

Effects of Hemodialysis Therapy Using Dialyzers with Medium Cut-Off Membranes on Middle Molecules

“…Despite the fact that high-flux membranes and hemodiafiltration (HDF) have enabled the clearance of the most widely studied middle molecule, β2-microglobulin (β2-M; molecular weight 12 kDa) [3,4] , there remain a number of larger middle molecules, such as κ and λ free light chains (FLC; molecular weights 23 and 45 kDa, respectively), which are still insufficiently removed. There is evidence that these larger middle molecules do exert toxic effects in concentrations that are encountered in uremic subjects and correlate with disease progression and mortality [5,6] .…”