Reduction of pro-inflammatory cytokine levels and cellular adhesion in CABG procedures with separated pulmonary and systemic extracorporeal circulation without an oxygenator

Objective: We have recently shown that a considerable amount of pro-inflammatory cytokines is released during pulmonary passage after aortic declamping in patients undergoing coronary artery bypass grafting. The present study was performed to investigate whether bilateral extracorporeal circulation with the lungs as oxygenators can reduce the inflammatory responses of the lungs. Methods: Eighteen consecutive patients undergoing coronary artery bypass grafting were randomly assigned to routine extracorporeal circulation with cannulation of right atrium and aorta (routine circulation, ten patients) or to a bilateral extracorporeal circulation with additional cannulation of left atrium and pulmonary artery (bilateral circulation, eight patients). Blood was simultaneously drawn from right atrium and pulmonary vein at 1, 10 and 20 min reperfusion. The levels of interleukin (IL)-6 and IL-8 and the adhesion molecules CD41 and CD62 on platelets and CD11b and CD41 on leukocytes were determined. Because of considerable interindividual scatter, the pulmonary venous levels are normalized to percent of the respective right atrial value at each time point. Results: At 1 min reperfusion pulmonary venous levels of IL-6 and IL-8 in routine circulation were +44±15% and +43±28% of the respective right atrial values. The respective values in bilateral circulation were ?3±4% and ?6±7% (P=0.02 and P=0.05 vs. respective right atrium). Similar increments were found after 10 and 20 min. Platelet–monocyte coaggregates were retained during pulmonary passage at 1 min reperfusion in routine circulation (?21±6%), but washed out in bilateral circulation (+5±8%, P=0.007). At 20 min reperfusion, activated polymorphonuclear neutrophils (PMN) were retained in routine circulation (?16±9%) but washed out in bilateral circulation (+19±29%, P=0.05; all data given as mean±SEM). Conclusions: Bilateral extracorporeal circulation without an artificial oxygenator significantly reduces the inflammatory responses during pulmonary passage after aortic declamping.