Off-Pump Coronary Surgery causes Immediate Release of Myocardial Damage Markers

Off-pump coronary surgery does not eliminate the risks of ischemia-reperfusion injury. The main objective of this study was to describe the extent and time course of changes in myocardial metabolism and development of myocardial injury associated with revascularization. Coronary sinus and arterial blood samples for measurement of troponin I, creatine kinase MB, lactate, glutathione, and interleukin-6 were taken from 23 patients prior to grafting, after completion of each anastomosis, and up to the 1st postoperative morning. The results were evaluated together with parameters of cardiac function. Release of lactate, creatinine kinase MB, and troponin I into the coronary sinus was evident after completion of the 1st graft, and increased over time. During the procedure, only trace amounts of oxidized and reduced glutathione were detected in coronary sinus and arterial blood. Significant increases in interleukin-6 were found in coronary sinus samples after 5 and 20min of reperfusion. Surgical trauma during off-pump coronary surgery is sufficient to activate an inflammatory response in the myocardium, together with unfavorable metabolic conditions to cause myocardial necrosis.