172 Early Hemodynamic Effect of Patent Ductus Arteriosus in Preterm Infants with Intra-Uterine Growth Restriction of Placental Origin

Abstract

Background: Significance of patent ductus arteriosus (PDA) is low during the first hours of life because of high pulmonary vascular resistance (PVR). However, clinical symptoms of significant PDA such as systemic hypotension, oliguria, hyperpulsatile pulses… are described early after birth in preterm infants with intra-uterine growth restriction (IUGR) of placental origin. We therefore hypothesized that significant ductal shunting can occur early after birth in IUGR. We compared the hemodynamic effects of PDA between 6 and 10 hours of life in IUGR versus eutrophic preterm infants. Methods: Infants from 24 to 32 weeks of gestational age (GA) admitted to our unit were prospectively studied. Exclusion criteria were: DA closure between 6 and 10 hours of life, premature rupture of membranes > 1 week, malformations, severe respiratory disease (FiO2 30 % and/or need for high frequency oscillatory ventilation), no antenatal corticosteroids, materno-fetal infection, need for vasoactive drugs, non-placental IUGR. The following parameters were assessed using bidimensional and Doppler echocardiography: left atrial aortic root ratio (LA:Ao), mean (mLPA) and telediastolic (tLPA) velocities in the left pulmonary artery, left ventricle shortening fraction (SF), DA diameter, mesenteric resistance index (MRI). Mean arterial blood pressure (MABP) and blood lactate level were also recorded. Results: 30 eutrophic and 19 IUGR infants were included (GA: 28.9±0.4 vs 28.9±0.5 weeks, NS; BW: 1300±60 vs 800±40 g, p<0.05, respectively). MABP, mLPA and SF were similar in both groups. The other parameters were significantly increased in IUGR infants: DA diameter (2.7±0.1 vs 2.1±0.1 mm, p<0.05), LA:Ao (1.5±0.08 vs 1.2±0.06, p<0.05), tLPA (0.23±0.02 vs 0.16±0.01 m/s, p<0.05), MRI (0.86±0.04 vs 0.7±0.02, p<0.05), lactate level (4.7±0.6 vs 3.1±0.3 mmol/l, p<0.05). Conclusion: Our results indicate that significant PDA may occur during the first 10 hrs of life in preterm infants with IUGR of placental origin. The hemodynamic consequences of PDA are higher in IUGR than in eutrophic preterm infants. The data suggest also that poor tolerance of PDA in IUGR infants is not due to an altered ventricular contractility but to a higher shunt flow through the DA. The significance of PDA should be assessed early after birth in IUGR.