Background: To investigate whether cardioplegia-related myocardial necrosis, lactate and glutathione release are predictive for early postoperative cardiac function after coronary artery bypass grafting (CABG).
Methods: Twelve patients with stabile angina scheduled for elective CABG were included. Myocardial release of troponin I (Tn I), creatine kinase MB isoenzyme mass (CK-MB), oxidized glutathione (GSSG) and lactate in blood were measured before cardioplegia, and up to 20 min thereafter. Cardiac function was assessed for 12 postoperative hours.
Results: Release of Tn I and CK-MB peaked at 20 min (-14.5+/-24.1 ng/ml and -23.9+/-30.6 ng/ml, respectively) and lactate at 1 min of reperfusion (-1.5+/-0.6 mmol/l). Significant GSSG release occurred at 5 min, with concomitant increase of glutathione redox ratio. The changes were not correlated to ischemic time. Cardiac index was increased after CPB and remained higher than preoperative value until the first postoperative morning. No correlations between postcardioplegic heart function and markers of tissue injury were found.
Conclusions: The extent of myocardial reversible and irreversible injury does not predict early postoperative contractile function of the heart.