Comparison of Solute Removal Properties Between High-Efficient Dialysis Modalities in Low Blood Flow Rate.

Blood flow (Qb) is one of the dialysis parameters most strongly influencing the performance of dialysis modalities. However, few studies have compared different dialysis modalities in patients with low Qb. We conducted a prospective, single-center study in 21 patients. Each patient underwent four dialysis sessions with routine dialysis parameters: high-flux hemodialysis (HD), predilution hemodiafiltration (pre-HDF), expanded HD (HDx), and postdilution HDF (post-HDF). The removal ratios (RR) of urea, creatinine, ß2 -microglobulin, myoglobin, prolactin, α1 -microglobulin, free kappa and lambda immunoglobulin light chains (ķFLC and λFLC), α1 -acid glycoprotein, and albumin were compared intraindividually. A proportional part of the dialysate was collected to quantify albumin loss. There were no differences in urea and creatinine RRs. The β2 -microglobulin RR was higher in pre-HDF and post-HDF. Myoglobin and prolactin RRs were higher with HDx and post-HDF. The α1 -microglobulin and α1 -acid glycoprotein RRs were significantly higher with post-HDF than with other treatments, and RRs obtained with HDx were higher than obtained with HD and pre-HDF. Free ķFLC and λFLC RRs showed the following results in ascending order: HD, pre-HDF, HDx, and post-HDF, most of them with statistical significance. Albumin loss varied from 0.45 g with HD to 3.5 g with post-HDF. The global removal score values were 41.0 ± 4.8% with HD, 44.0 ± 5.2% with pre-HDF, 49.5 ± 4.6% with HDx, and 54.8 ± 5.3% with post-HDF, with significant differences between all treatment modalities. In conclusion, this study confirms the superiority of post-HDF over high-flux HD, pre-HDF, and HDx in patients with low Qb. HDx was the closest alternative to post-HDF and was clearly superior to HD and pre-HDF. Finally, pre-HDF was also superior to HD. With this Qb, there was a higher risk of underdialysis, both diffusive and convective, especially in patients with a session duration of less than 5 h.