Effects of aprotinin on plasma levels of neutrophil elastase and postoperative blood loss in cardiac surgery.

This study evaluated the effects of aprotinin on plasma levels of elastase, platelet count, fibrinogen levels and postoperative bleeding. Thirty cardiac surgery patients were randomly chosen for this study. The protease inhibitor aprotinin was given in high doses to 20 patients before and during cardiopulmonary bypass; 10 patients served as the control group. Mean patient age and body weight was similar in both groups. There were no significant inter-group differences in the total cardiopulmonary bypass and cross-clamp times. Mean (s.e.m.) elastase levels were significantly raised in the control group (161.9(2.57) micrograms/l) compared with the treated group (148.2(3.29) micrograms/l) at 30 min of cardiopulmonary bypass (P < 0.01) and rose even further at the end of cardiopulmonary bypass, after protamine infusion, and 24 h postoperatively (P < 0.001). Platelet counts decreased more in the control group (P < 0.001). Serum fibrinogen levels were significantly lower in the controls during and just after cardiopulmonary bypass (P < 0.01). Postoperative blood loss was significantly less in the aprotinin-treated patients (315(25) ml) compared with the controls (589(154) ml) (P < 0.05). Aprotinin appears to inhibit elastase release and decrease postoperative blood loss.