Comparison of the efficacy of the cardiac hypothermia and normothermia to myocardial damage in coronary artery bypass graft surgery with systemic normothermic cardiopulmonary bypass

Aim. The aim of our research is to investigate the cardiac damage formed by either local cardiac hypothermia or cardiac normothermia technique in patients who undergone isolated coronary artery bypass graft (CABG) surgery. Methods. The total of 40 patients who underwent isolated CABG operation under normothermic cardiopulmonary bypass (CPB) were studied. Patients were randomly divided into two groups as cardiac hypothermia and cardiac normothermia. Myocardial temperature was measured from the interventricular septum before aortic cross-clamp (ACC) (baseline), the ACC 20th minutes (ischemia) and after 20 minutes removal of the ACC (reperfusion). The coronary sinus blood samples were simultaneously obtained from the retrograde cardioplegia cannula while myocardial temperature was being measured. Complement component 3 (C3), complement component 4 (C4), troponin I and tumor necrosis factor-alpha (TNF-alpha) was measured from the coronary sinus blood samples. Results. Myocardial temperature was between 18-28 degrees C (deep hypothermia) during ACC in group 1. Myocardial temperature was over 34 degrees C (normothermia) during ACC in group 2. TNF-alpha values of group 1 for ischemia and reperfusion were higher than group 2, and it was found statistically significant (P<0.05). Conclusion. Myocardial damage was less than in normothermia group according to hypothermia group. The results show that ice-cold blood cardioplegia and local ice treatment of the heart during CPB seems to harm the heart more than warm blood cardioplegia.