In Vitro Thrombogenicity Evaluation of Hemodialyzers

Investigation of dialyzer thrombogenicity is a critical step during the development of a new dialyzer. Novel dialyzer membranes aim to reduce the inherent thrombogenic potential of artificial surfaces by, e.g., increasing membrane hydrophilicity. Reliable in vitro testing is fundamental during dialyzer development and must be in line with the current standards. Using the novel FX CorAL dialyzer with its increased membrane hydrophilicity as an example, this study characterizes dialyzer thrombogenicity in an in vitro test setup in line with ISO 10993-4 and identifies factors which influence dialyzer thrombogenicity. In a recirculation setup with human blood, platelet activation (platelet counts, β-thromboglobulin, platelet adsorption), coagulation (thrombin-antithrombin III complex) and complement activation (sC5b-9) were investigated among polysulfone- (FX CorAL, FX CorDiax, Optiflux, xevonta), polyethersulfone- (ELISIO, Revaclear, Theranova) and AN69 ST-based (Nephral) dialyzers. Additionally, the impact of dialysate and electrolyte composition on thrombogenicity was investigated. The FX CorAL showed the lowest platelet activation compared to all poly(ether)sulfone-based dialyzers and lower complement activation compared to most poly(ether)sulfone-based dialyzers and to the Nephral dialyzer. No significant differences were observed between the investigated dialyzers with regard to plasmatic coagulation. Among the tested parameters, the dialyzer showed the strongest impact on the thrombogenicity results. This study proposes guidance on in vitro testing of dialyzer thrombogenicity in line with current standards and may contribute to reducing the current heterogeneity among in vitro hemocompatibility testing.