Pulmonary Artery Pressure Changes in Neonates

Abstract

Directly after birth, major changes in the respiratory and cardiovascular systems are required for postnatal survival, a dramatic reduction in pulmonary arterial pressure and resistance occurs with an increase in oxygen tension and blood flow. Circulatory physiology of the newborn goes through complex transitions in order to shift the respiratory function from the placenta to the lungs, characterized by the closure of fetal shunts, expansion of the lungs, and removal of placental circulation. Pulmonary hypertension presenting in the neonatal period can be due to persistent pulmonary hypertension of the newborn (PPHN), high output cardiac failure from large arteriovenous malformations and congenital heart malformations. Persistent exposure of the pulmonary vasculature to increased blood flow and pressure in patients with congenital heart diseases with left- to- right (systemic -to- pulmonary) shunts may result in vascular remodelling and dysfunction. Estimates of pulmonary artery pressure obtained using transthoracic echocardiography (TTE) are most commonly performed using continuous-wave Doppler to measure the maximum velocity of tricuspid regurgitation (TRVmax). This technique of pulmonary artery pressure quantification has been widely adopted for clinical and research purposes because it provides a noninvasive, direct estimate of right ventricular (RV) systolic pressure (RVSP) that correlates closely with invasive hemodynamic measurement. The present study aimed to evaluate changes in pulmonary artery pressure during neonatal period in full term newborns with congenital heart diseases with left to right shunts (VSD, ASD, PDA, AVSD) in comparison to healthy newborns. The current prospective study was conducted on 104 full term neonates were either admitted to the Children’s Hospital, Ain Shams University or from out patients clinic at the same hospital over a period from March 2014 to January 2016. Neonates were classified into 2 groups: Group I which included 52 full term neonates (≥ 37 weeks) with left to right cardiac shunts (ASD, VSD, AVSD and PDA) as a patients group and Group II which included 52 full term healthy neonates as a control group. After obtaining consents from the parents for participating in this study, all neonates in the study were subjected to history taking (antenatal, natal, postnatal and family history), clinical examination (BSA, systemic blood pressure, HR, RR, CRT) and echocardiography. Echocardiography was done for group I and group II at the 1st week of life and was repeated weekly till the 4th week of life. Comparison between patients group (group I)