Less inflammation by off-pump surgery? A randomized comparison to minimized extracorporeal circulation and conventional coronary bypass grafting

Objectives: Cardiopulmonary bypass causes systemic inflammation. Off-pump techniques and minimized systems aim for reduction of this reaction. However a three-sided comparison of minimized extracorporeal circulation (MECC) and conventional extracorporeal circulation (ONCAB) to off-pump coronary bypass grafting (OPCAB) is missing and the results of two-sided studies are inconclusive.

Methods: 60 patients scheduled for non-emergency isolated coronary bypass grafting were randomly assigned into three different study groups (ONCAB, MECC, OPCAB). Blood samples were taken at seven different time points. Inflammation markers (differential blood count, CRP, TNFalpha, ICAM-1 and P-selectin) and clinical parameters were assessed.

Results: In the overall study population leucocytes and neutrophil granulocytes increased already during the operation before protamine administration (p < 0.001). TNF showed a significant peak at arrival on ICU (p < 0.001) and stayed elevated over 72 hours. Both CRP and ICAM-1 increased significantly within 12 h after ICU-arrival (p < 0.001) and peaked at 24 h (p < 0.001). P-selectin dropped during the operation (p < 0.001) and returned to baseline at arrival on ICU. Body temperature increased significantly within 6 h after the operation (p < 0.001) and stayed elevated. However, the three surgical techniques showed similar curves without any significant differences in any of the parameters.

Conclusions: In this preliminary study OPCAB and MECC did not show any advantage over conventional CPB regarding systemic inflammation. Thus, more patients and further parameters focusing also on coagulation and organ impairment are currently investigated looking for the best surgical strategy.