Cardiac hypertrophy and altered hemodynamic adaptation in growth-restricted preterm infants

The objective was to elucidate hemodynamic adaptation in very low birth weight (<1500 g) infants after intrauterine growth retardation. 31 growth-retarded (SGA, birth weight <-2 SD) and 32 appropriate for gestational age (AGA, birth weight within +/- 1 SD range) infants were enrolled. In SGA infants, the diastolic diameters of the interventricular septum and the left ventricle were increased, and serum brain natriuretic peptide (BNP) was elevated. Left ventricular output (LVO) of the AGA infants increased from 150 +/- 28 to 283 +/- 82 mL/kg/min during the study (p < 0.01). The SGA infants had a higher initial LVO than the AGA infants (243 +/- 47 versus 150 +/- 28 mL/kg/min, p < 0.05), but did not show further LVO increase during the study period. Red cell (RCV) and blood (BV) volume were assessed by Hb subtype analysis, when packed donor red cells were transfused. RCV and BV did not differ between the groups initially, but RCV increased by 18% and BV by 29% in the AGA group during the first 3 d. On day 3, AGA infants had larger BV than the SGA infants (88 +/- 5 versus 73 +/- 12 mL/kg, p < 0.05). In conclusion, cardiac hypertrophy, elevated initial LVO and BNP of the SGA infants suggest increased cardiac workload after intrauterine growth retardation. Based on the BV and RCV data, blood volume regulation may also be impaired. The data suggest that SGA preterm infants may be exposed to an increased risk of circulatory failure during early adaptation.