c-peptide and Heart-Defects--Congenital

The aim of the study was to reveal differences in carbohydrate metabolism in children with cyanotic congenital heart diseases (CHD). Thirteen children with diseases of these kinds were investigated with regard to glucose tolerance and insulin secretion and comparisons were made with healthy controls of the same age. Investigations included an intravenous glucose tolerance test, insulin response to the glucose load in plasma and insulin secretion rate. The results reveal lower fasting glucose levels and signs of a higher insulin secretion rate in the relatively few patients in the CHD group where C-peptide measurements were performed, but no differences in glucose tolerance. The reasons for the differences are unclear, but the chronic increases in circulating catecholamines in combination with the impaired nutritional status of these children with CHD are probably the most important factors. We conclude that these divergences in carbohydrate metabolism should be emphasized in the care of children with CHD.

Topics: C-Peptide; Glucose; Heart Defects, Congenital; Humans; Infant; Insulin; Nutritional Status; Transposition of Great Vessels

Authors examined levels of glucose, insulin, and C-peptide in the plasma of 6 infants and small children with the isolated transposition of the great arteries (3 pts) and ventricular septal defect (3 pts) in the course of open-heart surgery in deep hypothermia. The mean age of the patients was 7.2 months (6 to 15) and weight 5.6 kg (5.2-7.5). Exogenous intake of glucose during the operation was excluded. Methods of anaesthesia, operation technique, and conduction of extracorporeal circulation (ECC) were constant in all patients. Fresh ACD blood diluted with Hartman solution approximately 1:1 was used for the prime of ECC circuit (content 800 ml) to get the hematocrit 0.27 +/- 0.2 after mixing the prime with the patient's blood volume. Glycemia was determined by Beckman ERA 2001 analyzor, and levels of insulin and C-peptide by radioimmunoassay kits MJ-96 (Poland) and Novo (Denmark). Significant hyperglycemia was found in all patients during the period of hypothermia, and was overlasting to the rewarming period until the end of the operation and 1 hour postoperatively. Then level of glycemia was decreasing to the normal values which were found in the last sample (17 hours post-op). The raise of glycemia was not a stimulus to the proportional increase of insulin and C-peptide levels in plasma. It proved transitional suppress of insulin secretion in the beta cells of the pancreas in the cooling period. Levels of insulin and C-peptide significantly and concordantly increased after 20 min. of rewarming (r = 0.83). However, hyperglycemia overlasted during the course of rewarming, too.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Blood Glucose; C-Peptide; Cardiac Surgical Procedures; Child, Preschool; Extracorporeal Circulation; Heart Defects, Congenital; Humans; Hypothermia, Induced; Insulin

Radioimmunoassays of plasma C-peptide, and plasma and erythrocyte insulin were made in mixed venous-arterial blood specimens of normal children and those with congenital heart diseases. In all cases, insulin level was higher in erythrocytes, as compared to plasma specimens, obviously due to active insulin deposition by erythrocytes. Venous-arterial difference in insulin may be indicative of tissue insulin uptake. Respiratory and circulatory hypoxia is associated with decreased erythrocyte capacity for insulin deposition and tissue insulin uptake. It is suggested that plasma C-peptide content may be an indicator of pancreatic function.

Topics: Biological Transport; C-Peptide; Child; Child, Preschool; Erythrocytes; Heart Defects, Congenital; Humans; Hydrocortisone; Hypoxia; Insulin; Insulin Secretion; Pancreas; Tissue Distribution