Synthetic protein treated versus heparin coated cardiopulmonary bypass surfaces: similar clinical results and minor biochemical differences

Objective: Complications associated with cardiopulmonary bypass (CPB) have gained more attention due to increased interest in coronary artery bypass g rafting without CPB. The impact of heparin coating of CPB circuits has been discussed controversially. The present study examines if the treatment of the oxygenator surface with a synthetic protein may serve as an alternative to a completely heparin coated circuit. Methods: Fifty-eight patients unde rgoing coronary artery bypass grafting with CPB were randomly assigned to c ompletely heparin coated circuits or synthetic protein treated oxygenators in a double blind protocol, focussing on the inflammatory reaction resultin g in membrane damage, coagulation changes and markers of cerebral injury or dysfunction. Treatment groups did not differ as to preoperative demographi cs, and intraoperative clinical data. Patients with any neurologic disease or risk factors for cerebral dysfunction were not included in the study. Re sults: Postoperative clinical data did not differ between groups. Both surf ace treatments resulted in similar coagulation activation, hyperfibrinolysi s and disseminated intravascular coagulation. Platelet count displayed a di fference in favour of the heparin coated group (P = 0.029), Increased leuko cyte activation reflected by rising myeloperoxidase concentrations on CPB w as present in both synthetic protein and heparin coating groups. Interleuki ns 6 and 8 reacted similarly, but interleukin 8 increased significantly mor e (P = 0.0061) at the end of surgery in patients treated with protein treat ed oxygenators. The same pattern was observed for complement activation as determined by total complement complex (P = 0.006). Both surface changes re sulted in moderately increased S-100B protein and neuron specific enolase, without difference between groups. Both markers did not reach concentration s associated with clinical manifestation of cerebral injury. Conclusions: T hese results in routine patients with short bypass time, imply that protein treated oxygenators are associated with a limited increase of biochemical markers similar to heparin coating. However, significantly lower interleuki n 8 release and complement activation can be achieved by heparin coating. T he protein treatment is a standard feature of the oxygenator examined in bo th groups. it is not associated with additional cost and therefore appropri ate for use in routine patients. (C) 1999 Elsevier Science B.V. All rights reserved.