Clinical data , myocardial damage assessed by myocard specific creatine kinase isoenzyme ( CK-MB ) , circulating whole blood levels of selenium , oxidative stress assessed by asymmetric dimethylarginine ( ADMA ) levels , antioxidant capacity determined by glutathionperoxidase ( GPx ) levels and perioperative inflammation represented by interleukin-6 ( IL-6 ) levels were measured at predefined perioperative time points .