Correlation of Patent Ductus Arteriosus Shunting with Plasma Atrial Natriuretic Factor Concentration in Preterm Infants with Respiratory Distress Syndrome

Abstract

ABSTRACT. The concentration of plasma atrial natriuretic factor (ANF) and the mechanism for its secretion were investigated in 17 preterm infants with respiratory distress. Their mean gestational age was 29 wk and wt 1250 g. The infants were followed during the first week of life by sequential Doppler ultrasound studies. Ductal openness versus closure and amount of ductal flow were correlated with plasma ANF concentrations. In a subset of 10 infants, sequential Doppler color flow mapping was used to quantify the ductal flow. During the first 72 h, plasma ANF was high, 361 pg/mL; it decreased to 96 pg/mL by the end of the 1st wk. (4, 5). In neonates with RDS (6) plasma concentration of ANF is increased compared to normal newborns. In these patients the peak plasma ANF concentration coincides with the diuretic phase found between 18 to 43 h of age (7).To clarify the association of ANF secretion and hemodynamic changes in preterm infants with RDS, we determined the Qp/Qs ratio and ductal closure by CFM with a method we developed previously (8). The focus of this study was the effect of ductal flow on plasma ANF concentration in preterm infants with RDS. MATERIALS AND METHODSSeventeen preterm infants (26-33 wk gestation) with birth wt of 0.66 to 1.95 kg (mean 1.25 kg) developed clinical signs and radiographic features consistent with RDS. Nine infants were delivered by caesarean section, and Apgar scores ranged from 3 to 8 at 1 min (mean 6) and from 6 to 9 at 5 min (mean 8). In 15 infants, analysis of amniotic fluid obtained within 24 h before birth revealed lecithin/sphingomyelin ratios less than 2.0 with absence of phosphatidylglycerol, and in two remaining infants tracheal aspirates obtained at birth contained no phosphatidylglycerol. These findings and the clinical course were consistent with severe RDS. This was further substantiated by calculating the arteriolar/alveolar oxygen tension ratio (9) at 6 h of age (0.17 5 0.08: mean + SD), which confirmed the disturbance in gas ANF, atrial natriuretic factor exchange and the requirement for supplemental oxygen and CFM, color flow mapping mechanical ventilation. Infants included in this study had no LA/Ao ratio, left atrial to aortic root diameter evidence of chorioamnionitis, congenital infection, or major PDA, patent ductus arteriosus malformations.Qp/Qs, pulmonic to systemic blood flow ratio Blood samples of 0.5 mL were drawn through umbilical artery catheters into ice-cold EDTA-containing tubes that were rapidly RDS, respiratory distress syndrome centrifuged at 300 x n. Plasma was sevarated for immediate freezingand stored at -3 0 "~ for up to 3 mo before ANF analysis. From each patient during the 1st wk of life, one to four samples were taken within 3 h of a CFM study. RIA was camed out as ANF is a secreted from the atria of the heart (1). In term previously described (10). Sensitivity of the method is 5 pg/mL. newborns plasma concentration of ANF is increased during the The intra-and interassay coefficients of variation are 10.6 and first 2 to 4 d of life (2,...

Role of atrial natriuretic factor in lung physiology and pathology.

“…In preterm infants with respiratory distress syndrome, the ductus arteriosus frequently remains patent during the first few days of life. A highly significant correlation has been reported between ANF secretion and the magnitude of left-to-right shunt through the patent ductus arteriosus (201). In addition, hypoxia and pulmonary hypertension probably also contribute to the elevation of plasma ANF levels in newborns with respiratory distress syndrome.…”

Atrial natriuretic peptide in the preterm infant. Lack of correlation with natriuresis and diuresis

“…Although plasma ANP was consistently higher in group 1 than in group 2, the postnatal change followed the same pattern in both groups. Earlier studies in preterm and fullterm neonates indicate a similar pattern postnatally with the highest values during the second day of life and very much lower levels in fullterm than in preterm infants (4,6,8). The weak negative correlation between plasma ANP and gestational age indicates a multifactorial influence on the plasma ANP concentration postnatally, e.g.…”

“…The capacity to release ANP is well developed already in the fetus (3) and preterm infants may have extremely high plasma ANP concentrations postnatally (4)(5)(6). The stimuli for ANP release are thought to be related to the postnatal circulatory changes associated with increased atrial pressure (4,7,8). Present knowledge of the renal effects of high plasma ANP levels in the neonate is scanty (4,6, The aim of this study was to evaluate the relation of plasma ANP concentration to renal function in preterm infants during the first few days of life.…”

Atrial natriuretic factor in amniotic fluid and in maternal venous blood of pregnancies with fetal cardiac malformations and chromosomal abnormalities

“…As has been well demonstrated, adult heart failure is associated with an enhancement of cardiac gene expression 14,15 , ventricular protein amount 16 Newborns affected with patent ductus arteriosus, leftto-right foramen ovale shunting and ventricular septal defect show higher ANF circulating values than do healthy subjects [18][19][20][21] . In patent ductus arteriosus, ANF levels become drastically lowered after medical or surgical therapy causing the duct closure and the restoring of atrial size 18 .…”