Changes in pulmonary artery pressure during early transitional circulation in healthy full-term newborns

Transitional circulation and hemodynamic monitoring in newborn infants

Transitional circulation is normally transient after birth but can vary markedly between infants. It is actually in a state of transition between fetal (in utero) and neonatal (postnatal) circulation. In the absence of definitive clinical trials, information from applied physiological studies can be used to facilitate clinical decision making in the presence of hemodynamic compromise. This review summarizes the peculiar physiological features of the circulation as it transitions from one phenotype into another in term and preterm infants. The common causes of hemodynamic compromise during transition, intact umbilical cord resuscitation, and advanced hemodynamic monitoring are discussed. IMPACT: Transitional circulation can vary markedly between infants. There are alterations in preload, contractility, and afterload during the transition of circulation after birth in term and preterm infants. Hemodynamic monitoring tools and technology during neonatal transition and utilization of bedside echocardiography during the neonatal transition are increasingly recognized. Understanding the cardiovascular physiology of transition can help clinicians in making better decisions while managing infants with hemodynamic compromise. The objective assessment of cardio-respiratory transition and understanding of physiology in normal and disease states have the potential of improving short- and long-term health outcomes.

Congenital diaphragmatic hernia-associated pulmonary hypertension

Congenital diaphragmatic hernia (CDH) is characterized by a developmental insult which compromises cardiopulmonary embryology and results in a diaphragmatic defect, allowing abdominal organs to herniate into the hemithorax. Among the significant pathophysiologic components of this condition is pulmonary hypertension (PH), alongside pulmonary hypoplasia and cardiac dysfunction. Fetal pulmonary vascular development coincides with lung development, with the pulmonary vasculature evolving alongside lung maturation. However, in CDH, this embryologic development is impaired which, in conjunction with external compression, stifle pulmonary vascular maturation, leading to reduced lung density, increased muscularization of the pulmonary vasculature, abnormal vascular responsiveness, and altered molecular signaling, all contributing to pulmonary arterial hypertension. Understanding CDH-associated PH (CDH-PH) is crucial for development of novel approaches and effective management due to its significant impact on morbidity and mortality. Antenatal and postnatal diagnostic methods aid in CDH risk stratification and, specifically, pulmonary hypertension, including fetal imaging and gas exchange assessments. Management strategies include lung protective ventilation, fluid optimization, pharmacotherapies including pulmonary vasodilators and hemodynamic support, and extracorporeal life support (ECLS) for refractory cases. Longitudinal re-evaluation is an important consideration due to the complexity and dynamic nature of CDH cardiopulmonary physiology. Emerging therapies such as fetal endoscopic tracheal occlusion and pharmacological interventions targeting key CDH pathophysiological mechanisms show promise but require further investigation. The complexity of CDH-PH underscores the importance of a multidisciplinary approach for optimal patient care and improved outcomes.

Interatrial Communications: Prevalence and Subtypes in 12,385 Newborns-a Copenhagen Baby Heart Study

The prevalence of interatrial communications in newborns, i.e., patent foramen ovale or atrial septal defect, was previously reported to be between 24 and 92%, but the area has been impeded by lack of a universal classification method. A recently published novel echocardiographic diagnostic algorithm for systematic classification of interatrial communications had inter-and intraobserver agreements superior to standard expert assessment. This study aimed to determine the prevalence of subtypes of interatrial communications on transthoracic echocardiography in newborns. Echocardiograms of newborns aged 0-30 days were prospectively collected in the population-based cohort study Copenhagen Baby Heart Study in 2017-2018 and analyzed according to the new diagnostic algorithm, classifying interatrial communications into three subtypes of patent foramen ovale and three subtypes of atrial septal defects. Echocardiograms from 15,801 newborns were analyzed; 3416 (21.6%) were excluded due to suboptimal image quality or severe structural heart disease (n = 3), leaving 12,385 newborns (aged 12 [interquartile range 8; 15] days, 48.2% female) included in the study. An interatrial communication was detected in 9766 (78.9%) newborns. According to the algorithm, 9029 (72.9%) had a patent foramen ovale, while 737 (6.0%) fulfilled criteria for an atrial septal defect, further divided into subtypes. An interatrial communication was seen on echocardiography in almost 80% of newborns aged 0-30 days. Patent foramen ovale was 12 times more frequent than atrial septal defects. The observed prevalence of atrial septal defects was higher than previously reported. Follow up studies could distinguish which interatrial communications require follow-up or intervention. ClinicalTrial.gov, NCT02753348, posted April 27, 2016, [ https://classic.clinicaltrials.gov/ct2/show/NCT02753348 ].

Dynamics of pulmonary hypertension severity in the first 48 h in neonates with prenatally diagnosed congenital diaphragmatic hernia

Introduction

Pulmonary hypertension (PH) is one of the major contributing factors to the high morbidity and mortality in neonates with congenital diaphragmatic hernia (CDH). The severity and duration of postnatal PH are an established risk factor for patient outcome; however, the early postnatal dynamics of PH have not been investigated. This study aims to describe the early course of PH in CDH infants, and its relation to established prognostic markers and outcome measures.

Methods

We performed a monocentric retrospective review of neonates with prenatally diagnosed CDH, who received three standardized echocardiographic examinations at 2-6 h, 24, and 48 h of life. The degree of PH was graded as one of three categories: mild/no, moderate, or severe PH. The characteristics of the three groups and their course of PH over 48 h were compared using univariate and correlational analyses.

Results

Of 165 eligible CDH cases, initial PH classification was mild/no in 28%, moderate in 35%, and severe PH in 37%. The course of PH varied markedly based on the initial staging. No patient with initial no/mild PH developed severe PH, required extracorporeal membrane oxygenation (ECMO)-therapy, or died. Of cases with initial severe PH, 63% had persistent PH at 48 h, 69% required ECMO, and 54% died. Risk factors for any PH included younger gestational age, intrathoracic liver herniation, prenatal fetoscopic endoluminal tracheal occlusion (FETO)-intervention, lower lung to head ratio (LHR), and total fetal lung volume (TFLV). Patients with moderate and severe PH showed similar characteristics, except liver position at 24- (p = 0.042) and 48 h (p = 0.001), mortality (p = 0.001), and ECMO-rate (p = 0.035).

Discussion

To our knowledge, this is the first study to systematically assess the dynamics of PH in the first postnatal 48 h at three defined time points. CDH infants with initial moderate and severe PH have a high variation in postnatal PH severity over the first 48 h of life. Patients with mild/no PH have less change in PH severity, and an excellent prognosis. Patients with severe PH at any point have a significantly higher risk for ECMO and mortality. Assessing PH within 2-6 h should be a primary goal in the care for CDH neonates.

Large scale application of pulse oximeter and auscultation in screening of neonatal congenital heart disease

Purpose

To conduct a retrospective evaluation of a large clinical implementation of combined pulse oximeter (POX) and cardiac auscultation as a fast-screening device for congenital heart disease (CHD).

Methods

Every newborn in a large maternity healthcare center received auscultation and POX screening within 24 hours after delivery. When an abnormal heart murmur or SpO₂ level was detected, an echocardiogram was ordered to confirm the diagnosis of CHD.

Results

From January 1, 2018 to December 31, 2019, there were 44,147 livebirths at the studied hospital where 498 suspected CHD were identified: 27 newborns by POX screening and 471 by cardiac auscultation. The diagnosis was further confirmed in 458 neonates through echocardiogram. This result put forth an overall diagnosis rate of 92.0%. Cardiac auscultation detected the majority of CHD cases 438 (95.6%) while POX only screened 20 (4.4%) cases. Interestingly, no CHD case was detected by both auscultation examination and POX screening. Auscultation detected most of the common types of CHD, but POX excelled in identifying rare and critical cases. POX screening alone had a very low accuracy of 74.07% in positive predict value (PPV). On the other hand, auscultation functioned well in terms of PPV and negative predict value (NPV) (92.99 and 99.95%, respectively), but the addition of POX improved the overall screening performance resulting in 100% NPV. We also validate the finding with the data 6 months after the study period.

Conclusion

Our study demonstrated that addition of pulse oximetry to routine cardiac auscultation could be used as an accurate and feasible screening for early screening of CHD in newborns in large-scale clinical practice.

Bedside cardiopulmonary ultrasonography evaluates lung water content in very low-weight preterm neonates with patent ductus arteriosus

BACKGROUND

Patent ductus arteriosus (PDA) is a common congenital heart abnormality in preterm neonates with a high incidence in neonates with very low birth weights. When PDA persists, interstitial lung water content increases, which could lead to abnormal circulation hemodynamics and pulmonary edema. It is important to perform early and reliable assessment of lung water content in very low-weight preterm neonates with persistent PDA.

AIM

To evaluate the role of bedside cardiopulmonary ultrasonography in the lung water content assessment in very low-weight preterm neonates with persistent PDA.

METHODS

From January 2018 to March 2020, 69 very low-weight preterm neonates with echocardiography-confirmed PDA were selected as the PDA group. At the same time, 89 very low-weight preterm neonates without PDA were randomly selected as the control group. All neonates underwent echocardiography and 6-segment lung ultrasonography on the fourth day after birth. The clinical characteristics and main ultrasonography results were compared between the two groups. Pearson's analysis was used to analyze the correlation between lung ultrasonography score (LUS) and other related clinical and ultrasonography results in all neonates. In the PDA group, PDA diameters were recorded, and the correlation with LUS and left atrium to aortic (LA/AO) dimension ratio were also analyzed. LA/AO ratio is one of the ultrasonic diagnostic criteria for hemodynamically significant PDA. When the ratio is ≥ 1.5, it suggests the possibility of hemodynamic changes in persistent PDA. A receiver operating characteristic curve was established using the sensitivity of LUS to predict the hemodynamic changes in neonates with PDA as the ordinate and 1-specificity as the abscissa.

RESULTS

A total of 158 neonates were enrolled in this study, including 69 in the PDA group and 89 in the control group. There were no statistical differences in sex, gestational age, birth weight, ventilator dependence, hospitalization length and left ventricular ejection fraction between the two groups (P > 0.05). The LUS and LA/AO ratio in the PDA group were higher than those in the control group (P < 0.05), but there was no difference of LUS in neonates with or without use of the ventilator (t = 0.58, P = 0.16). In all cases, LUS was negatively correlated with gestational age (r = -0.28, P < 0.01) and birth weight (r = -0.36, P < 0.01), while positively correlated with the LA/AO ratio (r = 0.27, P < 0.01). In the PDA group, PDA diameter was positively correlated with the LA/AO ratio (r = 0.39, P < 0.01) and LUS (r = 0.31, P < 0.01). Receiver operating characteristic results showed that LUS had the moderate accuracy for predicting hemodynamic changes in PDA (area under the curve = 0.741; sensitivity = 93.75%; specificity = 50.94%).

CONCLUSION

Bedside cardiopulmonary ultrasonography can evaluate lung content in neonates with PDA and predict the possibility of hemodynamic changes in persistent PDA.

Changes in the Interventricular Septal Curvature in Healthy Full-term Neonates During the First 14 Days of Life

OBJECTIVES

Interventricular septal geometry and motion reflect the interaction between the ventricles, and an abnormal shape and abnormal motion are always regarded as signs of increased right ventricular or pulmonary artery pressure. During the neonatal period, there are profound changes in the cardiac circulation. The aims of this study were to quantitatively analyze neonatal septal deformations under normal physiologic conditions and evaluate the changes in association with the hemodynamic changes occurring during the transitional period.

METHODS

This was a retrospective study of 114 healthy full-term neonates from birth to 14 days of age. Normalized septal curvatures were measured on left ventricular parasternal short-axis views during end diastole and end systole. The interventricular pressure gradient, ratio of ventricular volumes, septal strain, thickness, and some clinical characteristics were assessed, along with the association of these parameters with septal curvature.

RESULTS

All 4 normalized septal curvatures were found to have a significant correlation with the trans-septal pressure gradient (TSPG) and the end-diastolic volume ratio of the left and right ventricles (P < .0001). The TSPG had the highest impact on septal curvature, and among the 4 curvatures, the middle end-systolic normalized septal curvature had the highest correlation with the TSPG (r² = 0.948; P < .0001).

CONCLUSIONS

There were significant correlations between septal curvature and the interventricular pressure gradient and ventricular volume ratio in healthy full-term neonates. The normalized septal curvatures gradually increased with increasing age and could be good indicators of the hemodynamic changes occurring during the transitional period.

Lung Ultrasound Score Predicts the Extravascular Lung Water Content in Low-Birth-Weight Neonates with Patent Ductus Arteriosus

BACKGROUND Patent ductus arteriosus (PDA) is a common congenital cardiac abnormality in premature infants. In low-birth-weight infants weighing less than 2500 g, if the PDA continues to open, abnormal circulation hemodynamics and pulmonary edema may occur. This study aimed to investigate the role of lung ultrasound score in the assessment of pulmonary edema in low-weight neonates with PDA. MATERIAL AND METHODS Two hundred and twenty-one neonates with low birth weight were selected as the subjects, children with PDA as the observation group, and children with closed ductus arteriosus as the control group. On the fourth postnatal day, lung ultrasound examination and 6-segment lung ultrasound scoring were performed. RESULTS All 221 infants (94 in the observation group, 127 controls) underwent ultrasound examinations of the lungs. Intergroup differences in gestational age, birth weight, length of hospital stay, and left ventricular ejection fraction were not statistically significant. There was a significant difference in lung ultrasound score (t=0.005, P=0.000) and aortic root ratio to left atrial (t=0.085, P=0.000), which was negatively correlated with gestational age (r=-0.235, P=0.000) and positively correlated with PDA diameter (r=0.261, P=0.011). CONCLUSIONS Low-birth-weight children often have PDA. Its continued opening changes the circulation hemodynamics in children. Lung ultrasound score can semi-quantitatively evaluate the extravascular lung water content, identifying the need to intervene and follow up the hemodynamic significance of PDA over time.

Diagnostic analysis of abnormal increase of PASP in fetus in middle- and late-stage pregnancy by color Doppler echocardiography

OBJECTIVE

Our study was conducted with an attempt to investigate the diagnostic analysis of abnormal increase of fetal pulmonary artery systolic pressure (PASP) in middle and late pregnancy by color Doppler echocardiography.

METHODS

From August 2017 to January 2019, 52 fetuses with moderate or greater tricuspid high-speed regurgitation were retrospectively analyzed and selected as Group A. 88 fetuses with full-color blood flow of the two ventricles and symmetrical sizes of the cardiac cavities on both sides harboring tricuspid valve and mild regurgitation or a small amount of regurgitation were selected as Group B. The pulmonary artery blood flow acceleration time (AT) and right ventricular ejection time (ET) was measured, and the PASP was calculated.

RESULTS

The tricuspid regurgitation velocity, tricuspid regurgitation pressure difference and PASP in Group A were higher than those in Group B (p < 0.05), and the AT and AT/ET values in Group A were lower than those in Group B (p < 0.05). Gestational age, tricuspid regurgitation velocity and tricuspid regurgitation pressure difference were positively correlated with PASP. However, AT/ET and AT value were negatively correlated with PASP.

CONCLUSION

The abnormal increase of pulmonary artery can be assessed by color Doppler echocardiography of fetal tricuspid regurgitation, which is worth popularizing and applying in clinic.

ADVANCES IN KNOWLEDGE

It was suggested that the middle- and late-stage fetuses with moderate or greater tricuspid regurgitation and with >20 mmHg regurgitation pressure difference should be followed up in clinic. If PASP was ≥70 mmHg with symptoms of right heart failure, fetuses should be closely observed until 35-36 weeks old to ensure fetal safety and early delivery would be recommended.

Congenital diaphragmatic hernia-associated pulmonary hypertension

Congenital diaphragmatic hernia (CDH) is a neonatal pathology in which intrathoracic herniation of abdominal viscera via diaphragmatic defect results in aberrant pulmonary and cardiovascular development. Despite decades of study and many advances in the diagnosis and treatment of CDH, morbidity and mortality remain high, largely due to pulmonary hypertension (PH), along with pulmonary hypoplasia and cardiac dysfunction. In patients with CDH, hypoplastic pulmonary vasculature and alterations in multiple molecular pathways lead to pathophysiologic pulmonary vasculopathy and, for severe CDH, sustained, elevated pulmonary arterial pressures. This review addresses the multiple anatomic and physiologic changes that underlie CDH-associated PH (CDH-PH), along with the multimodal treatment strategies that exist currently and future therapies currently under investigation.

Congenital diaphragmatic hernia-associated pulmonary hypertension

Congenital diaphragmatic hernia (CDH) is a complex entity wherein a diaphragmatic defect allows intrathoracic herniation of intra-abdominal contents and both pulmonary parenchymal and vascular development are stifled. Pulmonary pathology and pathophysiology, including pulmonary hypoplasia and pulmonary hypertension, are hallmarks of CDH and are associated with disease severity. Pulmonary hypertension (PH) is sustained, supranormal pulmonary arterial pressure, and among patients with CDH (CDH-PH), is driven by hypoplastic pulmonary vasculature, including alterations at the molecular, cellular, and tissue levels, along with pathophysiologic pulmonary vasoreactivity. This review addresses the basic mechanisms, altered anatomy, definition, diagnosis, and management of CDH-PH. Further, emerging therapies targeting CDH-PH and PH are explored.

Dynamic Changes of Pulmonary Arterial Pressure and Ductus Arteriosus in Human Newborns From Birth to 72 Hours of Age

Normal pulmonary artery pressure and pulmonary hypertension assessment of newborns is rarely reported. The aim of the study is to explore dynamic changes of pulmonary arterial pressure and ductus arteriosus in human newborns from birth to 72 h of age with echocardiography.A total of 76 cases of normal newborns were prospectively detected by echocardiography after birth of 2 h, 6 h, 12 h, 24 h, 48 h, and 72 h, respectively. Ductus arteriosus diameter, blood shunt direction, blood flow velocity, and pressure gradient were recorded. The brachial artery blood pressure were measured to estimate the pulmonary artery systolic pressure (PASP) and pulmonary artery diastolic pressure (PADP) using patent ductus arteriosus pressure gradient method. The mean pulmonary artery pressure (PAMP) were calculated by equation of PAMP = PADP + 1/3(PASP-PADP).(1) There were 76 cases of normal newborns. Among them, 29 cases (38%) ductus arteriosus closed within 24 h, 59 cases (78%) closed within 48 h, 72 cases (95%) closed within 72 h, and 4 cases (5%) ductus arteriosus not closed within 72 h. (2) The ductus arteriosus diameter of 2 h, 6 h, 12 h, 24 h, 48 h, and 72 h after birth was 4.60 ± 0.59 mm, 3.37 ± 0.59 mm, 2.47 ± 0.49 mm, 1.89 ± 0.41 mm, 1.61 ± 0.35 mm, and 1.20 ± 0.24 mm, respectively. Compared all of the ductus arteriosus diameter of the above time periods, there were statistically differences with P < 0.05, respectively. (3) The mean PASP in 2 h, 6 h, 12 h, 24 h, 48 h, 72 h after birth were 76.58 ± 7.28 mm Hg, 65.53 ± 9.25mm Hg, 52.51 ± 9.07 mm Hg, 43.83 ± 7.90 mm Hg, 38.07 ± 8.26 mm Hg, and 36 ± 6.48 mm Hg, respectively. The PADP of the above time period were 37.88 ± 5.56 mm Hg, 29.93 ± 7.91 mm Hg, 23.43 ± 7.37 mm Hg, 19.70 ± 8.51 mm Hg, 13.85 ± 5.58 mm Hg, 13.25 ± 6.18 mm Hg, respectively. The PAMP of the above time period were 63.41 ± 7.03 mm Hg, 51.78 ± 9.82 mm Hg, 40.94 ± 9.32 mm Hg, 34.39 ± 9.89 mm Hg, 26.23 ± 7.49 mm Hg, 25.25 ± 8.29 mm Hg, respectively. There were statistically differences with P < 0.05 between each time periods of PASP, PADP, and PAMP. (4) The upper 95% limit reference range of PASP of normal newborns of 72 h after birth were 39.97 mm Hg.(1) Normal newborns ductus arteriosus diameter gradually decreased after birth, and 95% of them spontaneous closed within 24 to 72 h. (2) Normal newborns pulmonary artery pressure showed a gradually decline after birth, the upper 95% limit reference range for PASP measured in normal newborns <72 h of age was 39.97 mm Hg. Therefore, the diagnostic criteria of newborns pulmonary hypertension may be >40.00 mm Hg according to our limited study.