We observed a comparable inflammatory response in both groups, as Cefuroxime sodium reflected by a comparable perioperative time course of IL-6. This is according to previous studies which demonstrated the surgical trauma itself to represent the main reason for the proinflammatory response after both kinds of cardiac surgery. Previous findings in on-pump cardiac surgical patients indicate a higher level of oxidative stress when compared to patients undergoing OPCAB-surgery. In fact, the inevitable use of cardioplegic arrest during conventional on-pump surgery exposes patients to a significant longer duration of myocardial ischaemia and hence more pronounced reperfusion injury when compared to OPCAB-patients where myocardial I/R is minimized by the use of intracoronary shunts during performance of the distal UNC-2025 anastomoses. Furthermore, activation of immune cells after contact with the artificial surfaces of the extracorporeal circuit and the use of mild hypothermia might also contribute to the increased oxidative stress after CPB. Our findings of a comparable level of oxidative stress in both groups do however not support these considerations and do not allow to distinguish the effects of inflammation from those of oxidative stress. Interestingly, haemodilution and blood loss represent further possible causes for a decrease of circulating selenium levels. Of note, the intraoperative fluid balance differed significantly between our two study groups, most likely due to priming of the extracorporeal circuit with 1500 ml crystalloid fluid. However, postoperative haemoglobin concentration and the transfusion of packed red blood cells were comparable in both groups, suggesting that blood loss and haemodilution contributed only marginally to the observed selenium decreases. We acknowledge that the present trial suffers from several limitations, including a small sample size, which only allows an adequately analysis of the primary outcome parameter with sufficient statistical power. Analyses of the various secondary outcome parameters have to be considered to be purely explorative and hypothesis-generating.