Comparison of three strategies for myocardial protection during coronary artery bypass graft surgery based on markers of cardiac damage

Objectives: To evaluate myocardial damage during coronary artery bypass grafting using three different intermittent cardioplegia and then measuring cTnI and CKMBm release. Design and methods: Forty-two patients belonging to the hypothermic crystalloid (n = 16), hypothermic (n = 13), and normothermic blood (n = 13) groups were collected when removing the aortic cross-clamp (t = 0) and after 4, 12, 24 and 48 h. For each patient, cumulative cTnI and CKMBm release was calculated as the five measurement mean. There were no significant preoperative and operative differences in the three groups. Results: In the normothermic group, cTnI mean values at 4, 12, and 24 h were significantly lower than those in both hypothermic groups; moreover, CKMBm mean values were higher at 4, 12, and 24 h in the hypothermic crystalloid group and at 4 and 12 h in the hypothermic blood group than in the normothermic group. In the normothermic group, the area under the curve of the release of both markers was significantly lower than in the hypothermic groups. No significant difference was reported in the release of both markers in hypothermic groups. Conclusions: A strategy of normothermic cardioplegia seems to preserve myocardium better than hypothermic cardioplegia.