Metabolic Differences between Pediatric and Adult Hearts: Implications for Cardiac Surgery
Recent evidence suggests that during open heart surgery, pediatric hearts are more vulnerable to reperfusion injury compared to adult hearts. Metabolic differences between pediatric and adult myocardium may, in part, be responsible for the reported increased vulnerability of pediatric hearts. The aim of this work was to compare the metabolic state of both pediatric and adult hearts prior to open heart surgery. Ventricular biopsies were collected at the beginning of crossclamp time from hearts of 42 pediatric and 41 adult patients. Adenine nucleotides (ATP, ADP, AMP), purines (inosine, adenosine), amino acids (glutamate and alanine) and lactate were determined in all biopsies. There were no differences in the myocardial concentration of ATP, ADP, AMP, inosine and adenosine between pediatric and adult hearts. However, pediatric hearts had significantly higher lactate levels and lower levels of amino acids compared to adult hearts. These metabolic differences may offer an explanation for why pediatric hearts show more reperfusion injury than adult hearts during open heart surgery.
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