Objective: To evaluate whether off-pump surgery attenuates microalbuminuria and other markers of systemic inflammatory response to coronary artery bypass surgery as compared to surgery performed using cardiopulmonary bypass.
Design: Forty-three adult patients undergoing elective coronary artery bypass grafting surgery were operated on with or without cardiopulmonary bypass (CPB). Microalbuminuria, serum C-reactive protein, and oxygenation and lung function parameters were measured at several time points until the first postoperative morning.
Results: The urinary albumin/creatinine ratio was low in both groups before surgery, but reached a maximum level at the end of CPB or just after opening the last coronary artery clamp in the off-pump group (p<0.05). The urinary albumin/creatinine ratio remained slightly elevated in both groups until the morning after the operation (p<0.05). There were no statistical differences between groups. Serum C-reactive protein remained at the initial level the evening after the operation, but increased by the first postoperative morning in both groups (p<0.001). The alveolar-arterial gradient for oxygen partial pressure rose significantly after the operation in the intensive care unit in both groups (p<0.0001). The shunt fraction of the pulmonary circulation did not change in either group.
Conclusions: Off-pump coronary artery surgery did not prevent the acute phase inflammatory response measured in the present study. The acute phase inflammatory response after coronary artery bypass surgery is more likely a response to the surgical trauma itself rather than to CPB.