PurposeCurrently, the foreign surfaces of various extracorporeal circulation devices are coated with a biocompatible polymer coating agent (BPA), which creates a hydrophilic blood-contacting layer to reduce thrombogenicity, while the membranes in hemodialyzers are not. We aimed to clarify other side effects of BPA-coated membranes by examining the diffusion performance in in vitro experiments.MethodsWe used a polyethersulfone membrane (sieving coefficient of albumin is ≤0.01) coated with BPA product, SEC-1™ (Toyobo), in a hemodialyzer. To estimate the diffusion rates of a wide range of molecules, 2 L of saline containing vancomycin, lysozyme, and albumin were recirculated in the circuit configured with a hemodialyzer, and dialyzed continuously using water. The concentrations of sodium, vancomycin, lysozyme, and albumin were measured every 5 minutes for 30 minutes and compared in experiments with BPA-coated (n = 4) and BPA-noncoated (n = 4) membranes.ResultsThe removal rates of sodium and vancomycin after 5 minutes of dialysis (n = 24) were significantly higher in BPA-coated than noncoated membranes, while those of lysozyme and albumin were not significantly different. The removal rates of sodium and vancomycin after 30 minutes of dialysis (n = 4) were significantly higher, and those of lysozyme were significantly lower in BPA-coated than noncoated membranes, while those of albumin were not significantly different.ConclusionsThe preliminary study suggests that BPA-coated membranes enhanced the diffusion rate of molecules with low and middle molecular weight without affecting the sieving coefficient of albumin. Thus, BPA coating can enhance the dialysis performance of membranes.

Objective:Extracorporeal circulation devices are coated with a biocompatible polymer coating agent (BPCA) that has a hydrophilic blood-contacting layer, but hemofilters are not. We aimed to investigate the antithrombotic properties of a BPCA-coated hemofilter.Methods:Four experiments using BPCA-coated circuits and non-coated hemofilters and four experiments using BPCA-coated circuits and BPCA-coated hemofilters were performed with whole human blood and compared by measuring the circuit pressure every 5 min, antithrombin activity every 40 min, and thrombin–antithrombin complex every 40 min, for a total of 240 min of recirculation.Results:The mean time required for the pressure at the inlet of the hemofilter to increase sharply was longer in BPCA-coated than in non-coated hemofilters (66 ± 11 min vs 25 ± 9 min, p < 0.01). The mean antithrombin activity value at 200 and 240 min of recirculation was significantly higher in the experiments with BPCA-coated versus non-coated hemofilters (43.3 ± 2.87 vs 33.3 ± 5.74, p = 0.04; 42.8 ± 3.59 vs 31.0 ± 5.35, p = 0.01, respectively); the antithrombin activity values at the other time points were not significantly different. Furthermore, all thrombin–antithrombin complex values in experiments with the BPCA-coated hemofilters achieved overrange at 80 min of recirculation, whereas those with the non-coated hemofilter achieved overrange at 40 min.Conclusion:This study suggests that BPCA-coated hemofilters can inhibit antithrombin consumption, contributing to antithrombotic effects in extracorporeal circulation circuits.