Background: This prospective randomized study compared the inflammatory response in patients undergoing elective on-pump and off-pump coronary artery bypass grafting.
Patients and methods: Forty-four patients undergoing elective coronary artery bypass grafting were recruited with 22 patients randomized to on-pump heart surgery and 22 patients to off-pump coronary bypass surgery. Plasma levels of C3bc, the terminal SC5b-9 complement complex, myeloperoxidase, beta-thromboglobulin and prothrombin fragment F1 + 2 were measured before the operation, intraoperatively, at termination of the operation, and two hours post-operatively.
Results: Complement was markedly activated in the on-pump group as indicated by a significant increase in C3bc and SC5b-9 (p < 0.001 for both), whereas no complement activation was seen in the off-pump group (p = 0.001 between the groups). In contrast, both groups showed significant activation of neutrophils, platelets and coagulation, as indicated by an early increase in myeloperoxidase and a post-operative increase in beta-thromboglobulin and F1 + 2, respectively. Notably, there were no intergroup differences with regard to neutrophil and platelet activation, whereas coagulation activation was more pronounced in the off-pump group (p < 0.01).
Conclusions: Off-pump surgery completely eliminated the heart-lung machine-induced complement activation. Neutrophils and platelets were equally activated in both groups, whereas coagulation was enhanced post-operatively in the off-pump group.