Clinical efficacy and biocompatibility of three different leukocyte and fat removal filters during cardiac surgery.

Activated leukocytes and fat particles are associated with organ injury after a cardiac surgery. Filters are currently used to remove either leukocytes or fat particles. A novel approach with a filter that combines leukocyte and fat removal might be clinically useful. As it is not known which type of filter has a good and safe performance in both leukocyte and fat removal, we measured in this study the leukocyte and fat removal properties and the biocompatibility of three different filters. We used six Pall RS1 (Pall, Portsmouth, England) leukocyte removal filters, six Pall LipiGuard fat removal filters, and six Fresenius Biofil 02 (Fresenius, Emmer-Compascuum, The Netherlands) leukocyte removal filters and measured the passage times of 500 and 1000 mL of residual heart-lung machine blood. We determined the circulating leukocyte and platelet counts, and total hemoglobin, triglyceride, and free fatty acid concentration after the filters. In addition, we measured free hemoglobin, plasma elastase (Merck, Darmstadt, Germany), and complement C5-9 (Quidel, San Diego, CA, U.S.A.) to assess the biocompatibility of the filters. The circulating fat particles were calculated with an automated hematology analyzer. The passage time for the blood was shortest for the Biofil filter (P = 0.02, analysis of variance). The total leukocyte counts (P = 0.04) and fat particles (P = 0.02) were higher after the LipiGuard filter. This filter also had a higher increase in free hemoglobin concentration (P = 0.03). We conclude that the leukocyte removal filters were superior to the fat removal filter both in leukocyte and fat removal.