Complement activation during major surgery: The effect of extracorporeal circuits and high-dose aprotinin

Abstract

Objective: To assess the in vivo contribution to complement activation of an extracorporeal circuit and the use of high-dose aprotinin during major surgery. Design: Sequential samples were obtained from 8 patients undergoing thoracic surgery, 20 patients undergoing orthotopic liver transplantation (OLT) using venovenous bypass, and 19 patients undergoing cardiac surgery using cardiopulmonary bypass (CPB). Intervention: The latter two groups were part of a randomized controlled trial of high-dose aprotinin. Measurements: Total complement activation was measured with the hemolytic complement activity and the C3 activation-specific marker, C3d antigen. Main Results: Complement activation did not occur during thoracic surgery. During OLT, C3d antigen levels, expressed as mean ± standard deviation (SD), were elevated from baseline at skin closure (8.6 ± 2.5 v 13.0 ± 5.2 mg/L; p = 0.0082). During cardiac surgery, C3d antigen levels increased 10 minutes after the start of CPB (pre-CPB, 8.0 ± 1.9 v 14.2 ± 3.1 mg/L; p = 0.0001) and remained at greater than baseline values postoperatively (8.0 ± 1.9 v 11.8 ± 2.3 mg/L; p = 0.002). There was no difference in complement activation in those receiving high-dose aprotinin during OLT or cardiac surgery. Complement activation during cardiac surgery using extracorporeal circulation occurred to a greater extent than during OLT and thoracic surgery. Complement activation during cardiac surgery or OLT was not attenuated by the use of high-dose aprotinin.