Background: There is little evidence in the literature on the benefits of cold blood cardioplegia in pediatric cardiac surgery. This study investigates the effects of cold crystalloid versus cold blood cardioplegia on myocardial metabolism, reperfusion injury, and clinical outcomes in patients undergoing ventricular septal defect (VSD) repair.
Methods: Patients were randomly assigned to receive antegrade cold (4 to 6 degrees C) St Thomas's I crystalloid (CCC) or blood (CBC) cardioplegia. Changes in myocardial adenine nucleotides and purine levels were monitored in right ventricular biopsies and postoperative serum troponin I (TnI) and lactate release were measured.
Results: Forty patients were randomly assigned to CCC (n = 21; age 21.1 +/- 40.8 months) or to CBC (n = 19; age 27.4 +/- 39.3 months). Patient characteristics were similar in the two groups and there was no mortality. After the ischemic period there was a significant drop in adenosine triphosphate levels compared with control values in the CCC (40.4 +/- 9.9 versus 27.5 +/- 12.5 nmol/mg protein, p = 0.01) but not in the CBC group (40.3 +/- 23.2 versus 37.3 +/- 18.9 nmol/mg protein). The fall was more marked in infants compared with children (40% versus 10%, respectively, p = 0.01). Mean total TnI release was 42% lower in the CBC than the CBC group (95% confidence interval 10% to 62%, p = 0.015). Total TnI release was significantly associated with age (p < 0.001) but as levels in infants in the CBC group were the same as for children, the reduction with age was seen almost entirely in the CCC group. There were no differences in the duration of inotropic support, ventilation time, intensive care unit, or hospital stay in the two groups.
Conclusion: The use of CBC is associated with less metabolic myocardial ischemic stress and reperfusion injury when compared with CCC in pediatric patients undergoing VSD repair.