Randomized Cross‐Over Study to Examine Associations Between Dialyzer Clotting, Uremic Toxin Removal, and Hemocompatibility During Post‐Dilution Hemodiafiltration With Reduced Anticoagulation

To date, it remains unclear to what extent dialyzer performance is affected by clotting, and which hemocompatibility parameters can reliably predict this phenomenon. This study investigated the relationship between dialyzer clotting, performance, and hemocompatibility in four commercially available dialyzers under conditions of intentionally reduced anticoagulation. This crossover study included 10 chronic hemodialysis patients, who were randomized over four dialyzers: FX CorAL800, FX CorDiax800, xevonta Hi20 (all polysulfone-based), and Solacea-19H (cellulose-based). Patients received a single bolus of one-quarter of their standard Low-Molecular-Weight Heparin (LMWH) dose. Dialysis efficiency was assessed from toxin clearance of urea, β2-microglobulin, and myoglobin. Fiber patency was evaluated through visual scoring and μCT imaging. Hemocompatibility markers, including platelet counts, leukocyte counts, anti-Xa activity, thrombin-antithrombin complex (TAT), beta-thromboglobulin (β-TG), and neutrophil-activating peptide (NAP-2), were also analyzed. μCT analysis showed that Solacea dialyzer demonstrated superior fiber patency compared to the other dialyzers. However, fiber blockage did not compromise dialysis performance, as all dialyzers maintained effective toxin removal. Platelet and leukocyte counts remained stable with FX CorAL and Solacea, while declines were found in FX CorDiax and xevonta. No significant correlations were found between clotting parameters and fiber blockage. Hence, under reduced anticoagulation, the cellulose-based Solacea dialyzer exhibited superior fiber patency, but this did not result in higher middle molecule clearance. Since no correlation was found between fiber patency, dialysis performance, or clotting parameters, the underlying cause of the observed differences in dialyzer blockage remains unclear.