Splanchnic organ injury during coronary surgery with or without cardiopulmonary bypass: a randomized, controlled trial

Background We investigated the efficacy of coronary surgery with or without cardiopulmonary bypass in protecting the function of the small intestine, liver, and pancreas. Methods Patients were randomized to off-pump coronary artery bypass grafting (OPCAB) or coronary artery bypass grafting with cardiopulmonary bypass (CABG-CPB). Small intestine function was assessed by differential four sugars (O = methyl-D-glucose, D-xylose, L-rhamnose, and lactulose) permeability and absorption tests. Liver function was assessed by monoethylglycinexylidide/lidocaine ratios and by serial measurements of transaminases (aspartate transaminase and alanine-amino transferase), bilirubin, and alkaline phosphatase. Pancreatic function was assessed by serial measurements of insulin/glucagon ratio, amylase, and glucose. Forty patients were recruited (20 per group). Results Permeability and absorption were more impaired in the OPCAB group immediately after surgery, but returned to baseline levels in both groups by postoperative day 5 (interaction of surgery type and time; p = 0.05 and p = 0.02, respectively). Monoethylglycinexylidide/lidocaine ratios were not different in the two groups. Aspartate transaminase and alanine-amino transferase levels were higher in the CABG-CPB group for the first postoperative day, but levels converged by day 3 (interaction of surgery type and time; p <0.0001 and p = 0.04, respectively). The bilirubin level for the OPCAB group overshot the CABG-CPB group at 36 hours before returning to a similar level 60 hours postoperatively. Amylase levels were higher in the CABG-CPB group than in the OPCAB group (1.17 times; p = 0.03); other markers of pancreatic function showed no differences between the groups. Conclusions Early small intestine function is worse with OPCAB; all functions recover to similar levels in both groups by day 5. Conversely, pancreatic function is worse with the CABG-CPB group than with the OPCAB group. Hepatic metabolic function does not differ by type of surgery to the end of the operation. Postoperative hepatocellular injury was worse with the CABG-CPB group.