Inflammatory cytokine response and cardiac troponin I changes in cardiopulmonary bypass using two cardioplegia solutions; del Nido and modified St. Thomas’: a randomized controlled trial

BACKGROUND: Long intervals of del Nido (DN) solution administration, 90 minutes, may result in rewarming of the myocardial tissue and elevate metabolic demand and hypoxia. This will potentially increase inflammatory response due to ischemia-reperfusion injury. We conducted this study to compare the inflammatory response between patients receiving DN and multi-dose St Thomas' cardioplegia solution (MST) in cardiopulmonary bypass (CPB) surgery for the correction of tetralogy of Fallot (TF). METHODS: Fifty-nine pediatric patients undergoing TF total correction surgery were randomly assigned into two groups: DN and MST. The patients' demographic data, blood chemistry parameters, hemodynamics and other clinical variables were recorded. TNF-a, IL-6, IL-8, IL-10 and cTnI were measured after anesthesia induction (before skin incision), immediately after cross-clamp removal and 24 hours after admission to the intensive care unit (ICU). RESULTS: Thirty-two patients of a mean age of 28.0±16.4 months received DN and 27 patients of a mean age of 24.2±15.9 months received MST. Perioperative clinical parameters were not significantly different between the two groups. Cytokine levels for all patients were significantly increased after surgery. Inter-group comparisons of cytokine levels demonstrated no significant differences in TNF-α, IL-6 and IL-8 cytokines levels. IL-10 level showed a moderately significant increase in the MST group compared to the DN group after surgery (2.94±0.9 vs. 2.46±0.61 log10 pg/mL, respectively; p=0.039). Postoperative lactate level was significantly different between two groups (2.475±1.29 vs 1.63±0.82 mg/dL in DN and MST groups, respectively; p=0.007). CTnI levels increased after surgery and remained constant until 24 hours after surgery. Significant differences between the MST and DN groups, at all times, were not detected. CONCLUSIONS: The anti-inflammatory cytokine response in the MST group is significantly better than in the DN group. This may be due to shorter intervals of the MST cardioplegia solution administration, which prevents rewarming of the myocardium, increased metabolic demand and hypoxia. Decreasing the intervals of DN administration may improve its cardioprotective properties.