Platelet activation and aggregation during normothermic cardiopulmonary bypass.

OBJECTIVE

The usefulness of heparin-bonded circuits under normothermic cardiopulmonary bypass has not been elucidated. We studied platelet activation and aggregation differences between heparin-bonded and nonheparin-bonded circuits in patients undergoing surgery involving normothermic cardiopulmonary bypass.

METHODS

Eight patients underwent coronary artery bypass grafting with non heparin-bonded circuits (controls) and 7 the same with heparin-bonded circuits (heparin group). Heparin bonding was applied to the blood contact surface of our system, including the oxygenator and connecting tubes. Patient body temperature was kept between 36 and 37 degrees C. Beta-thromboglobulin and platelet factor 4 were measured before, during, and after cardiopulmonary bypass, and platelet aggregation was evaluated by laser-light scattering.

RESULTS

Changes in beta-thromboglobulin and platelet factor 4 during and after cardiopulmonary bypass were similar in both groups. Small particle formation was the primary aggregate induced during and after cardiopulmonary bypass in both groups, and serial changes in particle formation up to 24 hours after cardiopulmonary bypass were similar in both groups.

CONCLUSIONS

Our results indicate that in 2-3 hours of normothermic cardiopulmonary bypass, heparin-bonded circuits are similar to nonheparin-bonded ones in platelet compatibility.