Hyperamylasemia after cardiac surgery in infants and children

Objective: This study was conducted to clarify the incidence of hyperamylasemia after cardiac surgery in infants and children. Design and patients: 186 infants and children operated on at Children's Hospital, Helsinki, during an 11-month period were enrolled in the study. Serum samples were taken before and on 3 consecutive days after cardiac surgery at the intensive care unit and before discharge from the hospital. Measurements: We measured serum total amylase and serum pancreatic amylase with two different assays: (1) reduction of salivary amylase from total amylase activity and (2) measurement of mass concentration with monoclonal antibodies. Results: Preoperative values for both total amylase and pancreatic isoenzymes were strongly age-related. At least one of the three tests showed postoperative hyperamylasemia (> +2 SD above starting values of the age group and maximal value > 3 times the individual starting value) in 64/186 (34%) Patients. 22/186 (12%) patients had abnormal results in all assays. A more than tenfold rise in pancreatic amylase, suggesting pancreatitis, was found in 14 patients (8%). Mortality was 21% in this subgroup, but 5% in the rest of the patients, Hyperamylasemia was more common after 1 year of age, and after open-heart surgery, especially homograft implantation or cardiac transplantation. Conclusions: Hyperamylasemia is a common finding after cardiac surgery in pediatric patients. Amylase isoenzyme measurements are needed for clinical decision making. Age-group-related reference values are mandatory for the right interpretation of amylase values.