Expanded Hemodialysis Enhancement in Middle Molecule Clearance for Patients With Low Blood Flow Rates of Tunneled Dialysis Catheters.

Introduction: Expanded hemodialysis (HDx), being based on medium cut-off (MCO) membranes, improves the removal of medium molecule uremic toxins. HDx efficacy has been proven with blood flow rates (Qb) of 350-400 ml/min, while low Qb have only been assessed in single sessions. We evaluated the effectiveness of HDx in patients with tunneled central venous catheters (CVCs) and low Qb over six months, comparing it with high-flux hemodialysis (HF-HD).

Methods: The study included 10 patients with a mean age of 79±12 years and mean Qb of 237 ± 12 ml/min. Reduction ratios (RRs) and predialysis serum levels were measured for β2-microglobulin (B2M), free κ and λ light chains (FLC), prolactin (PRL), interleukin-6 (IL-6), albumin, and urea after HF-HD and at one, three, and six months of HDx. Erythropoiesis-stimulating agent (ESA) resistance index (ERI) was also evaluated.

Results: B2M, κ-FLC, λ-FLC, and PRL RRs were significantly higher with HDx. IL-6, albumin, and urea RRs did not show a statistical difference between the two treatments. Predialysis B2M concentrations were significantly lower after three and six months of HDx, matching up to increased B2M clearance (spKt/V). A decrease in albumin concentrations was observed, with median levels significantly reduced at months seven and eight (35.3 and 35.5 g/L, respectively) but recovering afterwards. ERI was significantly lower during HDx, reaching a 30% reduction at month six.

Conclusions: HDx was feasible, safe, and superior to HF-HD in patients with low Qb rates of tunneled dialysis catheters. The present data expand options for HDx prescription, with particular regard for patients who cannot achieve high convective volumes due to inadequate vascular access.