Pediatric Cardioplegia Strategy Results in Enhanced Calcium Metabolism and Lower Serum Troponin T

Background: Pediatric myocardium is unique from mature myocardium; thus, the use of adult cardioplegia for pediatric cardiac operations may provide suboptimal myocardial protection. We evaluated our standard adult cardioplegia (AC; modified Buckberg) and a pediatric cardioplegia (PC) solution (del Nido solution, Baxter) in vitro in rat cardiomyocytes and compared short-term outcomes in pediatric cardiac surgical patients. Methods: Contractions, intracellular calcium, and action potentials were recorded from isolated rat cardiomyocytes exposed to PC or AC, followed by reperfusion. Pediatric patients (n = 118) undergoing cardiac operations using PC (group PC, n = 59) or AC (group AC, n = 59) were matched 1:1 for age, diagnosis, and duration of cardiopulmonary bypass. Results: PC-perfused rat ventricular cardiomyocytes had lower diastolic calcium during cardioplegia and early reperfusion than AC-perfused cardiomyocytes. Cardiomyocytes remained excitable despite introduction of AC but not PC. The mean age in each pediatric group was 3.7 years (range, 3 days to 17 years; p = 0.95). Median serum troponin T levels at intensive care admission were significantly lower in group PC (0.83 ± 0.25 μg/L) than in group AC (13.8 ± 12.7 μg/L, p = 0.0001), which persisted at 24 hours postoperatively. There were no significant differences in duration of intubation or length of stay in intensive care or the hospital. Conclusions: Pediatric cardioplegia is associated with reduced intracellular diastolic calcium during arrest and reperfusion and more complete arrest during exposure in rat cardiomyocytes. Pediatric patients receiving pediatric cardioplegia had reduced troponin T release compared with those receiving adult cardioplegia.