Comparison of three oxygenator-coated and one total-circuit-coated extracorporeal devices

The present study was designed to compare the biocompatibility of three cardiopulmonary bypass setups with different surface coatings, and to determine if coating of the whole circuit with one of the coatings was more beneficial than coating of the oxygenator only. Extracorporeal devices entirely coated with synthetic polymers (Avecor, n = 6) were compared to oxygenators coated with synthetic polymers (Avecor, n = 6), end-point, covalently attached heparin (CBAS, n = 6) or absorbed heparin (Duraflo 2, n = 6) in an in vitro model of a heart–lung machine. The circuits were primed with fresh human whole blood and Ringer’s acetate and recirculated at 4 l/min at 30°C for 2 h. Test samples were obtained at regular intervals and analysed for myeloperoxidase (MPO), platelet counts, b-thromboglobulin, heparin, prothrombin fragment 1+2, plasmin–anti-plasmin complexes, and complement activation products. The mean MPO concentrations increased in the Avecor-coated oxygenator group (AV) from 247 at the start to 671 m g/l at the termination of th