Clinical/biochemical aspects of myocardium protection efficiency during major surgery of congenital heart diseases in infants

Clinical/biochemical characteristics of myocardial protection efficiency in infants with congenital heart disease (CHD) operated under extracorporeal circulation (ECC) were studied by using various methods for protection of the myocardium. Clinical criteria were evaluated in 154 patients, with 42 of them subjected to crystalloid chemical/ hypothermic cardioplegia (CCHC), 26 - to blood cardioplegia and 86 - to Custodiol cardioplegic solution. Full assessment of ECG parameters was carried out progressively during the early postoperative period and 1 - 5 days after operation. Also assessed were ECG parameters of diastolic dysfunction (DD) of the left ventricle and the time course of specific markers of myocardial injury 1-5 days after operation: CK - MB activity and troponin I level. It was found out that in a number of patients some ECG signs of subepicardial and subendocardial ischemia were observed in the early postoperative period. The ischemia was of a transitory nature, with a share of patients who had the signs of subepicardial disorders remaining the same by the 1st postoperative day and that of patients with subendocardial disorders reducing by half during the same time. By the 3rd postoperative day there was a considerable decrease in the share of patients with the signs of subepicardial ischemia, while the number of patients with subendocardial ischemia remained the same, which correlated with the severity of cardiac insufficiency. The area of subepicardial ischemia was mainly localized in the lower and lateral wall. While comparing the methods of myocardial protection, it was found out that in the early postoperative period subepicardial ischemia was mostly observed in the crystalloid chemical/hypo-thermic cardioplegia group and the hematic cardioplegia group as compared with the Custodial group. It was also noted that by the 1st postoperative day the Custodiol group had the least number of patients with the signs of subepicardial ischemic disorders. After performing open-heart surgery in infants we managed to determine a «surgical stress-norm» of specific markers, CK-MB and troponin I, which might serve as a diagnostic criterion to identify the signs of perioperative injury of neonatal myocardium that underwent a surgical trauma and extracorporeal circulation at the background of its chemical/hypothermic protection.