linoleic-acid and Heart-Defects--Congenital

Growth retardation is common in infants with congenital heart defects. The aim of this study was to investigate whether growth retardation or type of heart defect in infants with congenital heart defects is related to disturbances in lipid metabolism. Sixteen infants with ventricular septal defects and six infants with transposition of the great arteries were given an intravenous load of lipid emulsion (Intralipid 20 mg/ml) corresponding to 0.5 g fat/kg body weight for 5 min after fasting for 8 h. Blood samples were drawn immediately before the infusion and 3, 20, 60, 120 and 240 min after the infusion was completed. Plasma concentrations of triglycerides (TG), free fatty acids (FFA), ketones, lactate, pyruvate, alanine, glycerol and glucose were determined. The fatty acid patterns in the TG and FFA fractions were measured using gas chromatography. Severe growth retardation in infants with defects of these kinds was correlated to higher fasting and maximum levels of linoleic acid in plasma FFA. The maximum levels of linoleic acid in the TG fraction were positively correlated to weight SD score, and maximum glycerol levels were higher in the most growth-retarded infants, indicating faster intravascular lipolysis. Linoleic acid in the TG fraction was still elevated at 120 and 240 min after the lipid load. Some differences between the cyanotic and VSD groups could be noted. These indicate decreased metabolic capacity to utilize released FFA in the cyanotic group. Infants with cyanotic heart defects also had higher lactate and alanine levels compared to infants with VSD. Our results support the hypothesis that lipid metabolism is disturbed in infants with congenital heart defects.

Topics: Alanine; Blood Glucose; Chromatography, Gas; Chromatography, Thin Layer; Fat Emulsions, Intravenous; Fatty Acids, Nonesterified; Fluorometry; Glycerol; Growth Disorders; Heart Defects, Congenital; Humans; Infant; Infant, Newborn; Ketones; Lactates; Linoleic Acid; Lipolysis; Pyruvic Acid; Severity of Illness Index; Triglycerides

We describe the use of two in vitro tests to characterize plasma antioxidant capacity at the time of cardiac bypass in operations for congenital heart disease in 30 patients aged 3 days to 16 years (average 4.4 +/- 0.9 years [standard error]). Bypass and crossclamp time, circuit volume, and type of operation were recorded for each patient. First, a test of plasma radical antioxidant power measured chain breaking (secondary) antioxidant capacity of plasma to prevent oxidation of linoleic acid in vitro. Second, overall ability of plasma to prevent lipid peroxidation was assessed by a classic test of plasma inhibition of malondialdehyde formation in a beef brain homogenate. Plasma total radical antioxidant power level at baseline was 0.74 +/- 0.03 mumol/ml plasma, which decreased to 0.15 +/- 0.05 mumol/ml plasma after bypass (p < 0.001) and 0.26 +/- 0.08 mumol/ml plasma with recovery (n = 18, p < 0.001). Analysis of variance of postbypass total radical antioxidant power value showed age (p = 0.0002, r = 0.63) and bypass time (p = 0.009, r = 0.4677) to be significant factors. Pump prime volume in milliliters per kilogram and preoperative hemoglobin value were not significant factors. Beef brain malondialdehyde formation in vitro was limited 92% +/- 3% by normal plasma before operation versus 53% +/- 5% after operation (p < 0.001) and 51% +/- 5% at recovery after arrival in the pediatric intensive care unit (p < 0.001). Analysis of variance of the changes from before to after operation showed age p = 0.0015, r = 0.55) and bypass time (p = 0.033, r = 0.39) to be significant factors. Thus antioxidant capacity of plasma is significantly diminished after cardiopulmonary bypass in children. Young patient age and long duration of cardiopulmonary bypass are identified as factors that correlate positively with depletion of antioxidant capacity with bypass.

Topics: Adolescent; Analysis of Variance; Animals; Antioxidants; Brain; Cardiopulmonary Bypass; Cattle; Child; Child, Preschool; Heart Defects, Congenital; Humans; In Vitro Techniques; Infant; Infant, Newborn; Linoleic Acid; Linoleic Acids; Lipid Peroxidation; Malondialdehyde; Oxidation-Reduction; Oxygen Consumption; Postoperative Period; Reperfusion Injury