Oxidative stress during coronary artery bypass operations: Importance of surgical trauma and drug treatment

Objective. To investigate oxidative stress and myocardial injury at different stages of coronary artery bypass grafting (CABG). Design. Twenty patients underwent CABG with use of cardiopulmonary bypass (CPB) and with intermittent sampling of plasma and urine. Main markers were: 8-iso-PGF(2 alpha) (oxidative stress); troponin T (myocardial injury); and 15-keto-dihydro-PGF2 alpha and hsCRP (inflammation). Results. Plasma 8-iso-PGF2 alpha increased after start of surgery, but there was no further rise during CPB or after aortic cross-clamp release and no significant myocardial arterio-venous differences. An increase in troponin T was seen early after the operation, but no relationship was established between 8-iso-PGF2 alpha and troponin T. 8-iso-PGF2 alpha levels were elevated by preoperative withdrawal of acetylsalicylic acid (ASA) but reduced by intraoperative use of heparin. 15-keto-dihydro-PGF2 alpha was elevated during operation and hsCRP following operation. Conclusions. In the present study oxidative stress was multifactorial in origin with main impacts from surgical trauma, less from CPB and little if any from myocardial ischemia-reperfusion events. In addition, cardiovascular drugs in common use like ASA and heparin seemed to influence the pro- and antioxidant balance, a finding that has to be confirmed in future studies.