HEPARIN COATING REDUCES BLOOD-CELL ADHESION TO ARTERIAL FILTERS DURING CORONARY-BYPASS - A CLINICAL-STUDY

Deleterious effects of cardiopulmonary bypass (CPB) are partly sequelae of blood-foreign surface reactions. Coating the inner surfaces of CPB sets with heparin has been shown to decrease activation of humoral cascade systems. The aim of this study was to investigate whether the heparin-coated CPB sets influence adhesion of blood cells to surfaces of arterial filters during CPB. Thirty-one patients undergoing coronary artery bypass grafting were studied. In the control group (C) standard CPB sets and standard doses of heparin (300 IU/kg) were employed; in the HC (heparin-coated) group, heparin-coated CPB sets and reduced heparin doses (range, 150 to 225 IU/kg) were used. Two additional groups were also studied; group FC (coated filter), with standard CPB sets and heparin-coated arterial filters (heparin dose, 300 IU/kg), and group OC (uncoated filter), with heparin-coated CPB sets and standard arterial filters (heparin dose, 300 IU/kg). The inner surfaces of the arterial filters were examined after CPB with scanning electron microscopy. Scanning electron microscopy demonstrated almost clean surfaces in heparin-coated filters even when other parts of the circuit were uncoated. Using an arbitrary adhesion score, significant differences between the groups were noted in the adhesion grade; it was lowest in group HC (2.2 +/- 0.27 [mean +/- standard error of the mean]) versus group C (5.4 +/- 0.53; p < 0.001). In group FC it was marginally higher than in group HC but almost significantly lower than in group OC (2.6 +/- 0.68 versus 5.4 +/- 0.81; p = 0.05). We conclude that heparin coating of arterial filters diminishes cellular adhesion to the filter surface during CPB. This effect seems to be independent of surface characteristics in other parts of the circuit.