Effects of aprotinin on heparin activities and heparin neutralization with protamine

In order to investigate the new situation in which aprotinin is proposed as a novel approach to reducing post operative bleeding, specially in cardiopulmonary bypass (CPB) surgery during which heparin and protamine are commonly used, preliminary in vitro and in vivo studies have been performed. Aprotinin increases the anticoagulant heparin effects in vitro, and the hemorrhage time in vivo. But in addition to protamine, there are no statistically significant differences with heparin-protamine situation, indicating aprotinin does not disturb the neutralizing activities of protamine on heparin.