Early pulmonary vascular disease in preterm infants at risk for bronchopulmonary dysplasia

Current and Emerging Therapies for Prevention and Treatment of Bronchopulmonary Dysplasia in Preterm Infants

Although advances in the care of extremely preterm born infants have yielded improvements in survival and reductions in important morbidities, rates of bronchopulmonary dysplasia (BPD) have remained relatively unchanged. As BPD can have a long-lasting impact on the quality of life for survivors of prematurity and their families, this remains a continuing challenge. Treatments that have consistently shown efficacy in preventing either BPD or the composite outcome of BPD and death prior to 36 weeks post menstrual age (PMA) in large-scale randomized clinical trials (RCTs) include caffeine [adjusted odds ratio aOR for BPD, 0.63; 95% confidence interval (95% CI) 0.52-0.76; p < 0.001)], vitamin A [relative risk (RR) for death or BPD 0.89; 95% CI 0.80-0.99], low-dose hydrocortisone in the first week of life [OR for survival without BPD, 1.45; 95% CI 1.11-1.90; p = 0.007], and post-natal dexamethasone [RR for BPD or mortality; 0.76; 95% CI 0.66-0.87]. Although early caffeine therapy is now a widely used strategy to prevent BPD, the potentially severe side effects of post-natal glucocorticoids and the concerns regarding the cost-benefit of vitamin A have led to inconsistent use of these drugs in clinical practice. Inhaled bronchodilators and diuretics provide differing degrees of symptomatic relief for patients according to their phenotypic pattern of lung injury; however, these medications do not prevent BPD. Currently available pharmaceuticals do not sufficiently address the degree of structural immaturity and immune dysregulation that is present in the growing population of survivors born prior to 25 weeks gestational age. In this article, we provide both an evidence-based summary of pharmacological treatments currently available to prevent and manage BPD and a discussion of emerging therapies that could help preserve normal lung development in infants born preterm.

Pulmonary vasodilator use in very preterm infants in United States children's hospitals

OBJECTIVES

To describe common pulmonary vasodilators (PV), exposure timing, and characteristics associated with their use in very preterm (VP) infants.

STUDY DESIGN

Observational study of VP infants discharged from U.S. children's hospitals (2011-2021). PV exposures during hospitalization were identified, and multivariable modeling determined characteristics associated with exposure.

RESULTS

Among 37,428 infants, 6.3% received PV. Early inhaled nitric oxide (iNO) and late sildenafil were most common. Early exposure was associated with lower gestational age, aOR: 9.2 (7.3-11.7), 22-25 vs. 29-31 weeks) and small for gestational age (SGA), 2.3 (2.0-2.7). Late exposure was associated with bronchopulmonary dysplasia (BPD) grade, 26.2 (16.8-40.9), grade 3 vs. no BPD) and early PV exposure, 3.7 (2.9-4.8).

CONCLUSIONS

Early iNO and late sildenafil are used in VP infants despite limited evidence. Prospective early studies enrolling extremely preterm and SGA infants and late studies enrolling infants with early PV exposure and high-grade BPD would target current evidence gaps.

Bronchopulmonary Dysplasia-Associated Pulmonary Hypertension: Screening and Management

Screening for pulmonary hypertension (PH) in infants with bronchopulmonary dysplasia (BPD) was recommended by the American Thoracic Society in 2015. However, the definition of BPD has since changed. This review summarizes the current definition of BPD, the recommendations and tools for screening for PH in infants with BPD, and the various treatment options and outcomes in infants with BPD-PH.

Association between early pulmonary arterial pressure measurements and bronchopulmonary dysplasia or mortality in very preterm infants: a prospective cohort study

BACKGROUND

Prematurity is a significant risk for bronchopulmonary dysplasia related pulmonary artery pressure.

OBJECTIVE

To determine the association between pulmonary artery pressure in the early days of life and the development of bronchopulmonary dysplasia or mortality.

METHODS

This prospective observational cohort study included infants born at <32 weeks and weighing <1500 g. Pulmonary artery pressure was measured between postnatal days 3 and 7. Pulmonary hypertension was defined as systolic pulmonary artery pressure ≥40 mm Hg or systolic pulmonary artery pressure/systolic blood pressure >0.5 (pulmonary hypertension criterion-1). Infants were categorised into pulmonary hypertension and non-pulmonary hypertension groups. The primary endpoint was bronchopulmonary dysplasia or mortality. Receiver operating characteristic analysis established a new threshold value for predicting bronchopulmonary dysplasia or mortality (pulmonary hypertension criterion-2). Infants were reanalysed according to new criteria.

RESULTS

A total of 329 infants were included in this study. Moderate-to-severe pulmonary hypertension was identified in 24% (n=79) of the infants. The pulmonary hypertension group exhibited a significantly lower gestational age, lower birth weight and a higher incidence of small for gestational age. Systolic pulmonary artery pressure >25 mm Hg or systolic pulmonary artery pressure/systolic blood pressure >0.35 was defined as the pulmonary hypertension criterion-2. Logistic regression analysis identified pulmonary hypertension criterion-2 as an independent risk factor for moderate-to-severe bronchopulmonary dysplasia or mortality (OR 2.67, 95% CI 1.3 to 5.51, p<0.01).

CONCLUSION

Pulmonary artery pressure exceeding 25 mm Hg in the early days of life may be considered a potential risk factor for bronchopulmonary dysplasia or mortality.

Intraamniotic vitamin D preserves lung development and prevents pulmonary hypertension in experimental bronchopulmonary dysplasia due to intraamniotic sFlt-1

Preterm infants born to mothers with preeclampsia, a disease of vascular dysfunction, are at increased risk for bronchopulmonary dysplasia (BPD). Endothelial cells are critical in both maintaining proper vascular function and coordinating lung development. Understanding the mechanisms contributing to BPD in the setting of preeclampsia and how preeclampsia impacts pulmonary endothelial cells (PECs) in the newborn lung are required to decrease the burden of BPD. Vitamin D has been shown to improve lung angiogenesis and lung development in inflammatory models of BPD, but its therapeutic potential in the setting of preeclampsia is unknown. We hypothesized that intraamniotic (IA) treatment with the biologically active form of vitamin D, 1,25 dihydroxyvitamin D [1,25(OH)2D], will preserve lung growth in an experimental model of BPD induced by antenatal exposure to soluble vascular endothelial growth factor receptor-1 [sFlt-1 (soluble fms-like tyrosine kinase 1)]. Fetal rats were exposed to saline (control), sFlt-1 alone, 1,25(OH)2D alone, or simultaneous sFlt-1 + 1,25(OH)2D via IA injection during the late canalicular stage of lung development and delivered 2 days later. IA treatment with 1,25(OH)2D in sFlt-1-exposed pups improved lung alveolar and vascular growth and function at 14 days of life. PECs orchestrate alveolar development, and we demonstrate that IA sFlt-1 exposure alone decreased in vitro growth and tube formation of PECs isolated from newborn pups and that PECs from pups coexposed to IA sFlt-1 and 1,25(OH)2D demonstrated increased growth and tube formation. We conclude that IA 1,25(OH)2D treatment improves distal lung development during sFlt-1 exposure through preservation of angiogenesis in the developing lung.NEW & NOTEWORTHY This study highlights that experimental BPD induced by intraamniotic sFlt-1 is associated with impaired growth in postnatal pulmonary endothelial cells. We demonstrate that 1,25(OH)2D may be a therapeutic option to improve lung development through enhancement of VEGF signaling and preservation of early pulmonary endothelial growth in the newborn rat lung.

Characteristics and sex differences in bronchopulmonary dysplasia-related pulmonary hypertension

BACKGROUND

Pulmonary hypertension (PH) secondary to bronchopulmonary dysplasia (BPD) is associated with increased mortality. This study aims to elucidate the risk factors for BPD-PH development and the long-term prognostic factors in pediatric BPD.

METHODS

We analyzed 1082 BPD patients under the age of three. Univariate and multivariate regression were performed to determine the final model. Risk stratification was performed based on the predicted risk score, and Kaplan-Meier survival curves were used to compare survival rates.

RESULTS

The in-hospital mortality rate of severe BPD was three times than non-severe BPD, and pediatric BPD-PH had twice the mortality compared to BPD without PH. The incidence of BPD was 1.7 times higher in males, but there were no sex-specific differences in BPD severity. However, female children with BPD had a higher likelihood of developing BPD-PH and lower survival rates. Females, severity of BPD, congenital diaphragmatic hernia, ventricular septal defect, patent ductus arteriosus, uric acid, aspartate aminotransferase/alanine transaminase (ALT), and albumin were independent factors of PH in BPD. Severity of BPD, PH, severe pneumonia, budesonide use, use of adrenaline or noradrenaline, ALT, and day of respiratory support were independent factors for overall survival in pediatric BPD. Two web servers were constructed based on these predictive factors for risk prediction of BPD-PH ( https://sex-ph.shinyapps.io/Nomapp1/ ) and overall survival prediction in BPD patients ( https://zds88.shinyapps.io/DynNomapp/ ).

CONCLUSION

This study confirmed sex differences in BPD-PH and emphasized the role of sex in the development and prognosis of the disease. Two web servers predicted personalized PH risk and survival outcomes in BPD.

Celastrol has beneficial effects on pulmonary hypertension associated with bronchopulmonary dysplasia: Preclinical study outcomes

Pulmonary hypertension associated with bronchopulmonary dysplasia (BPD-PH) is a severe cardiorespiratory disease of preterm newborns leading to an excess of mortality in infancy and no curative treatment currently exists. Inflammation and oxidative stress are the common pathways that lead to BPD-PH. Therefore, we aimed to evaluate celastrol, a molecule with anti-inflammatory and antioxidant properties, as a promising preventive treatment in BPD-PH. In a model of neonatal rats exposed to hyperoxia, we demonstrated that mortality was prevented in animals treated with celastrol. Moreover, in vivo, celastrol decreased pulmonary hypertension, right ventricular hypertrophy, vascular remodeling, pulmonary arterial hyperreactivity to endothelin-1 and inflammation but had no effect on hypoalveolarization and altered angiogenesis. In vitro experiments carried out on human fetal pulmonary artery smooth muscle cells (HfPA-SMC) exposed to hyperoxia showed that endothelin-1-induced intracellular calcium response was increased and celastrol significantly inhibited this effect, without modifying endothelin-1 receptors expression. Regarding inflammation, celastrol decreased both CD68 staining in lung and secretion of the pro-inflammatory cytokine Tissue Inhibitor of Metalloproteinases-1 in intrapulmonary arteries from neonatal rats. IL-6 secretion was also decreased by celastrol in HfPA-SMC. Finally, hyperoxia increased heme oxygenase-1 (HO-1) expression and celastrol induced an overexpression of HO-1 in both neonatal rat lung and human cells. These results suggest that celastrol has a preventive effect on major hallmarks of PH in both a rat hyperoxic model of BPD-PH and HfPA-SMC exposed to hyperoxia via modulation of macrophage inflammatory signaling and HfPA-SMC calcium cycling. Celastrol could therefore be considered as a promising preventive treatment in BPD-PH.

Inhaled Nitric Oxide Treatment of Early Pulmonary Hypertension to Reduce the Risk of Death or Bronchopulmonary Dysplasia in Infants Born Extremely Preterm: A Masked Randomized Controlled Trial

OBJECTIVE

To determine whether inhaled nitric oxide (iNO) treatment of early pulmonary hypertension (PH) would decrease the risk of death or bronchopulmonary dysplasia (BPD) among infants born extremely preterm.

STUDY DESIGN

This was a single-center, masked, randomized controlled trial involving infants born at ≤29 weeks' gestation and requiring positive pressure ventilation. Exclusion criteria included infants of COVID-19 positive mothers, large patent ductus arteriosus with left to right shunting, left ventricle dysfunction (ejection fraction <40%), significant congenital anomalies/genetic disorders, or iNO treatment by clinicians prior to the study echocardiogram. Initial echocardiogram was performed at 72 ± 24 hours of life to randomize infants with early PH into 2 study arms (iNO vs placebo). Serial echocardiograms were performed every 24-48 hours, up to 14 days of life. Treatment was weaned until PH resolved (responders) or if no improvement was documented ≥72-hours (nonresponders). Primary outcome was death or BPD at 36-weeks postmenstrual age.

RESULTS

From July 2019 to October 2023, 683 eligible infants were admitted. We excluded 88 infants; 413 mothers declined consent or were not approached. iNO treatment was clinically started for 51 infants due to hypoxic respiratory failure. Screening echocardiograms were completed for 180 infants; of these, 32 infants with early PH were randomized to iNO or placebo groups. After a planned interim analysis, termination of the trial was recommended by the Data Safety Monitoring Committee because of futility.

CONCLUSION

iNO treatment does not reduce the risk of BPD or death among extremely preterm infants with echocardiographic evidence of early pulmonary hypertension without hypoxic respiratory failure.

Risk Factors Associated With the Development of Late Pulmonary Artery Hypertension in Extremely Premature Infants

OBJECTIVE

To identify risk factors for late pulmonary artery hypertension (PH) at 36 weeks' postmenstrual age (PMA) in infants born before 28 weeks' gestation.

DESIGN/METHODS

A retrospective cohort study included infants born < 28 weeks' gestation who underwent PH screening echocardiography at 36 weeks' PMA. We compared characteristics between infants with and without late PH to determine associations.

RESULTS

Of 99 infants, 20 (20%) developed late PH. The FiO2% requirement at 4 weeks of age, home oxygen use, and procedural patent ductus arteriosus closure were associated with late PH. Bronchopulmonary dysplasia (BPD) severity was linearly associated with late PH, with each 1-point increase in BPD severity corresponding to a 3.5-fold increased odds of late PH diagnosis.

CONCLUSION(S)

One in five extremely premature infants developed late PH. Markers of respiratory disease severity, including the BPD grade, were associated with the development of late PH.

Outcomes of infants and children with bronchopulmonary dysplasia-associated pulmonary hypertension who required home ventilation

BACKGROUND

To characterize a cohort of ventilator-dependent infants and children with bronchopulmonary dysplasia-associated pulmonary hypertension (BPD-PH) and to describe their cardiorespiratory outcomes.

METHODS

Subjects with BPD on chronic home ventilation were recruited from outpatient clinics. PH was defined by its presence on ≥1 cardiac catheterization or echocardiogram on or after 36 weeks post-menstrual age. Kaplan-Meier analysis was used to compare the timing of key events.

RESULTS

Of the 154 subjects, 93 (60.4%) had PH and of those, 52 (55.9%) required PH-specific medications. The ages at tracheostomy, transition to home ventilator, and hospital discharge were older in those with PH. Most subjects were weaned off oxygen and liberated from the ventilator by 5 years of age, which did not occur later in subjects with PH. The mortality rate after initial discharge was 2.6%.

CONCLUSIONS

The majority of infants with BPD-PH receiving chronic invasive ventilation at home survived after initial discharge. Subjects with BPD-PH improved over time as evidenced by weaning off oxygen and PH medications, ventilator liberation, and tracheostomy decannulation. While the presence of PH was not associated with later ventilator liberation or decannulation, the use of PH medications may be a marker of a more protracted disease trajectory.

IMPACT STATEMENT

There is limited data on long-term outcomes of children with bronchopulmonary dysplasia (BPD) who receive chronic invasive ventilation at home, and no data on those with the comorbidity of pulmonary hypertension (PH). Almost all subjects with BPD-PH who were on chronic invasive ventilation at home survived after their initial hospital discharge. Subjects with BPD-PH improved over time as evidenced by weaning off oxygen, PH medications, liberation from the ventilator, and tracheostomy decannulation. The presence of PH did not result in later ventilator liberation or decannulation; however, the use of outpatient PH medications was associated with later ventilation liberation and decannulation.

PDA management strategies and pulmonary hypertension in extreme preterm infants with bronchopulmonary dysplasia

BACKGROUND

Premature infants are at risk for developing pulmonary hypertension (PH) in the context of bronchopulmonary dysplasia (BPD). Studies suggest a potential link between prolonged patent ductus arteriosus (PDA) exposure and BPD-PH, though management strategies remain controversial.

METHODS

Retrospective echocardiographic evaluation of newborns <29 weeks gestational age with BPD at two distinct centers. Primary objective was to evaluate the relationship between center-specific PDA management strategies (interventional or conservative) and the prevalence of BPD-PH. BPD was defined as oxygen or respiratory support at 36 weeks post-menstrual age (PMA). The presence of PH was defined as either an estimated sPAP of ≥40 mmHg or sEI ≥1.3. Center A has a conservative PDA policy. Center B has a targeted interventional policy.

RESULTS

PH rates were similar between sites (21% vs 17%), while rates of PDA treatment was different (7% vs 81). Adjusted models did not demonstrate an association for center or PDA treatment exposure for PH and EI, although infants from Center A had echocardiography evidence of higher systolic eccentricity index (EI; 1.12 ± 0.19 vs 1.06 ± 0.15, p = 0.04). Markers of RV function (TAPSE and RV-FAC) were similar between groups.

CONCLUSION

In preterm infants <29 weeks with BPD, conservative PDA treatment policy was not associated with higher rate of pulmonary hypertension diagnosis.

IMPACT

The association between PDA-management approaches and the occurrence of BPD-associated pulmonary vascular disease in premature infants has sparsely been described. We found that a conservative policy, regarding the PDA, was not associated with an increase in pulmonary hypertension diagnosis. We identified that, in patients with BPD, echocardiographic metrics of LV performance were lower.

Characterizing the Role of Left Ventricular Indices and Biventricular Interaction in Bronchopulmonary Dysplasia-Associated Pulmonary Hypertension in Extreme Prematurity

INTRODUCTION

Bronchopulmonary dysplasia (BPD) is a common respiratory morbidity in preterm infants. The onset of pulmonary hypertension leads to worse respiratory outcomes. The contribution of left ventricular diastolic dysfunction in BPD-PH is well reported. We evaluated the serial left ventricular function and possible ventricular interdependence among BPD-PH.

METHODS

This is a single-center, prospective observational study. Infants <28 weeks of gestation are included.

RESULTS

Eighty infants were enrolled. The incidence of BPD-PH was 23%. The BPD-PH group had a high incidence of hemodynamically significant ductus arteriosus (83% vs. 56%, p < 0.018), longer oxygen days (96.2 ± 68.1 vs. 59.35 ± 52, p < 0.008), and prolonged hospital stay (133.8 ± 46 vs. 106.5 ± 38 days, p < 0.005). Serial tissue Doppler imaging showed prolonged left ventricle (LV) isovolumetric contraction time (IVCT) (31.05 ± 3.3 vs. 26.8 ± 4.4 ms, p < 0.001) and myocardial performance index (MPI) (0.43 ± 0.03 vs. 0.37 ± 0.04, p < 0.001) from 33 weeks. The changes in IVCT (35.9 ± 6.7 vs. 27.9 ± 4.5 ms, p < 0.001), isovolumetric relaxation time (IVRT) (50 ± 6.5 vs. 39.9 ± 5.8 ms, p < 0.001), and MPI (0.48 ± 0.05 vs. 0.36 ± 0.03, p < 0.001) persisted at 36 weeks. The receiver operator characteristic curve showed LV MPI >40 has 83% sensitivity and 65% specificity (AUC: 0.77, p < 0.001) in the diagnosis of PH. The BPD-PH group had a higher LV E/E' ratio (13.1 ± 4.4 vs. 11.4 ± 3.4, p < 0.02). Pearson correlation test showed a moderate positive correlation between RV MPI and LV MPI (r = 0.585, p < 0.001).

CONCLUSIONS

Significant LV diastolic dysfunction was observed in BPD-PH. This is the first study to show biventricular strain and possible ventricular interdependence in BPD-PH. The prolonged LV IVRT and MPI may be a novel echocardiographic indicator of BPD-PH.

Risk factors and clinical outcomes of pulmonary hypertension associated with bronchopulmonary dysplasia in extremely premature infants: A systematic review and meta-analysis

This systematic review and meta-analysis evaluated the risk factors for bronchopulmonary dysplasia associated pulmonary hypertension (BPD-PH) in extremely premature infants (gestational age < 32 weeks) and its impact on outcomes. A computerized search of eight databases was performed, from the time of library construction to February 2024. The quality of the included studies was assessed with the Newcastle‒Ottawa scale. Statistical analyses were performed using RevMan 5.4.1 and Stata 16.0 software. Meta-analysis of 2137 extremely premature infants revealed that oligohydramnios (OR = 2.21, 95% CI 1.06-4.61), low gestational age (SMD = -0.36, 95% CI -0.47 to -0.24), low birth weight (SMD = -0.54, 95% CI -0.74 to -0.35), small for gestational age (OR = 1.61, 95% CI 1.06-2.44), neonatal respiratory distress syndrome (OR = 2.05, 95% CI 1.45-2.91), grade III bronchopulmonary dysplasia (OR = 4.67, 95% CI 1.34-16.30), and sepsis (OR = 2.25, 95% CI 1.69-4.66) were risk factors for BPD-PH, whereas antenatal steroids (OR = 0.66, 95% CI 0.49-0.88) were protective factors. BPD-PH led to the extension of oxygen therapy (SMD = 0.67, 95% CI 0.42-0.92) and hospital stay (SMD = 0.77, 95% CI 0.14-1.40), and elevated the risk of discharged on oxygen (OR = 2.77, 95% CI 1.35-5.70) and death (OR = 4.38, 95% CI 2.21-8.69). BPD-PH is a multifactorial disease. In this study, a total of seven risk factors, and one protective factor for BPD-PH were identified in extremely premature infants. By managing and mitigating these factors, it is possible to decrease the occurrence of BPD-PH. Furthermore, BPD-PH may increase the risk of a poor prognosis in extremely premature infants.

Neonatal Risk Factors for Pulmonary Vein Stenosis in Infants Born Preterm with Severe Bronchopulmonary Dysplasia

OBJECTIVE

To evaluate associations between neonatal risk factors and pulmonary vein stenosis (PVS) among infants born preterm with severe bronchopulmonary dysplasia (sBPD).

STUDY DESIGN

We performed a case-control study of infants born from 2010 to 2022 at <32 weeks' gestation with sBPD among 46 neonatal intensive care units in the Children's Hospitals Neonatal Consortium. Cases with PVS were matched to controls using epoch of diagnosis (2010-2016; 2017-2022) and hospital. Multivariable logistic regression analyses were utilized to evaluate PVS association with neonatal risk factors.

RESULTS

From 10 171 preterm infants with sBPD, we identified 109 cases with PVS and matched those to 327 controls. The prevalence of PVS (1.07%) rose between epochs (0.8% in 2010-2016 to 1.2% in 2017-2022). Relative to controls, infants with PVS were more likely to be <500 g at birth, to be small for gestational age <10th%ile, or have surgical necrotizing enterocolitis, atrial septal defects, or pulmonary hypertension. In multivariable models, these associations persisted, and small for gestational age, surgical necrotizing enterocolitis, atrial septal defects, and pulmonary hypertension were each independently associated with PVS. Among infants on respiratory support at 36 weeks' postmenstrual age, infants with PVS had 4.3-fold higher odds of receiving mechanical ventilation at 36 weeks' postmenstrual age. Infants with PVS also had 3.6-fold higher odds of in-hospital mortality relative to controls.

CONCLUSIONS

In a large cohort of preterm infants with sBPD, multiple independent, neonatal risk factors are associated with PVS. These results lay important groundwork for the development of targeted screening to guide the diagnosis and management of PVS in preterm infants with sBPD.

Pulmonary hypertension in preterm neonates with bronchopulmonary dysplasia: a meta-analysis

CONTEXT

Knowledge gaps exist on the incidence and risk factors for developing pulmonary hypertension (PH) in preterm infants with bronchopulmonary dysplasia (BPD) and its impact on outcomes.

OBJECTIVE

To systematically review and meta-analyse the incidence, risk factors and short- and long-term outcomes of BPD-PH in preterm infants.

DESIGN

PubMed, Embase, Cochrane CENTRAL and CINAHL were searched for studies including infants<37 weeks gestational age (GA) or birth weight<2500 g with BPD-PH versus BPD-no PH from inception until 5 April 2023.

MAIN OUTCOME MEASURES

Incidence, risk factors and short- and long-term outcomes.

RESULTS

44 observational studies evaluating 7677 preterm infants were included. The incidence of PH in mild, moderate and severe BPD was 5%, 18% and 41%, respectively. Small for GA (25 studies; N=5814; OR 1.8; 95% CI 1.3, 2.5), necrotising enterocolitis (22 studies; N=3387; OR 1.6; 95% CI 1.3, 2.2), early PH (four studies; N=820 OR 2.2; 95% CI 1.5, 3.3) and severe BPD (20 studies; N=2587; OR 5.4; 95% CI 3.2, 9.1) were significant risk factors for BPD-PH. Compared with BPD-no PH, the BPD-PH group had significantly higher mortality (22 studies; N=4882; OR 6.4; 95% CI 4.7, 8.6), longer duration of mechanical ventilation, oxygen supplementation, length of hospital stay, need for home oxygen and tracheostomy requirement. The BPD-PH infants also had a significantly higher risk of neurodevelopmental impairment in the motor domain.

CONCLUSIONS

PH increases across the severity of BPD and is associated with higher odds of mortality and adverse short-term and neurodevelopmental outcomes.

PROSPERO REGISTRATION NUMBER

CRD42023413119.

Longitudinal evaluation of hemodynamic blood and echocardiographic biomarkers for the prediction of BPD and BPD-related pulmonary hypertension in very-low-birth-weight preterm infants

Very-low-birth-weight infants (VLBW, < 1500 g) are at risk of developing bronchopulmonary dysplasia (BPD) and are at risk for BPD-related pulmonary hypertension (PH). The longitudinal measurement of innovative blood and echocardiographic biomarkers might allow for a risk stratification of these infants. A prospective single-center cohort study was conducted between 01/2021 and 06/2023. Inclusion criteria were the combination of a birth weight < 1500 g and a gestational age (GA) ≤ 30/0 weeks. Assessment timepoints: T1 (day 7), T2 (day 28), and T3 (at 36 weeks post-menstrual age, PMA). Overall, 71 preterm infants were included for final analysis. The Zlog-transformed NTproBNPZlog (at T1 AUC 0.772; p = 0.019; at T2 AUC 0.874, p = 0.002), and endothelin-1 (ET1, at T1 AUC 0.789, p = 0.013) were identified as an early predictive biomarker for BPD/death in the univariate analysis. Additionally, echocardiographic markers of ventricular function and PH at T1 were predictive for BPD/death in the univariate analysis, with the highest predictivity found for the tricuspid annular plane systolic excursion-TAPSE (AUC 0.748, p = 0.016) and the pulmonary artery acceleration time to right ventricular ejection time (PAAT/RVET; AUC 0.744, p = 0.043). Regarding predictability of mortality alone NTroBNPZlog (at T1 AUC 0.973, p = 0.000), and CA125 (at T1 AUC 0.747, p = 0.008) were identified as potential predictors, as well as TAPSE (AUC 0.926, p = 0.000), and PAAT/RVET (AUC 0.985, p = 0.000) Several biomarkers including ET-1 (at T1 AUC 0.893, p = 0.000), TAPSE (AUC 0.974, p = 0.000), and PAAT/RVET (AUC 1.0, p = 0.000) at T1 were identified as univariate predictors for BPD-PH. In the multivariate analysis, no biomarker was identified as an independent predictor of the primary endpoint.

CONCLUSION

Mainly at an early stage of postnatal neonatal care in VLBW preterm infants, several biomarkers were found to be associated with the combined endpoint BPD/death and BPD-PH. New candidates of blood biomarkers (NTproBNPZlog, ET-1, and CA125) and echocardiographic markers (TAPSE, PAAT/RVET) might serve as innovative predictors for BPD, BPD-PH, and adverse outcomes in VBLW infants.

WHAT IS KNOWN

• VLBW infants are at risk for the development of BPD and BPD-related PH, which both are main contributors for short and long-term morbidity and mortality. Several studies in the past focused on the evaluation of circulating blood biomarkers and biomarkers from echocardiographic assessment of these infants. But to date, there is still a lack on longitudinal prospective studies especially in VLBW infants.

WHAT IS NEW

• For the first time, this set of selected blood biomarkers (with the first description of Zlog-transformed NTproBNP and CA125 in preterm infants) and several echocardiographic markers were analyzed in a prospective longitudinal study from birth until 36 weeks post menstrual age in VLBW infants. Our data help clinicians to identify preterm infants at risk for BPD, BPD-PH and death and to offer new candidates of biomarkers. This might help to facilitate decision making and guidance of therapy in these highly vulnerable patients.

Longitudinal echocardiographic parameters for evaluation of pulmonary hypertension in preterm infants with very low birth weight

BACKGROUND

Echocardiography is essential for the evaluation of pulmonary hypertension. We determined the feasible quantitative parameter for screening and monitoring pulmonary hypertension in preterm infants.

METHODS

This secondary analysis of a prospective cohort single-centre study was conducted between August 2019 and September 2020. Serial echocardiography was performed 7 and 28 days after birth and at 36 weeks postmenstrual age. The data of infants who developed pulmonary hypertension at 36 weeks postmenstrual age were compared with those without pulmonary hypertension. We also modelled the parameters' trend and performed an interaction test using multi-level Gaussian regression.

RESULTS

Out of 30 infants enrolled in the study, 79 echocardiograms were analysed. Left ventricular eccentric index was obtainable in all infants, while tricuspid jet velocity was measurable in 44.1%. Left ventricular eccentric index correlated well with tricuspid regurgitation jet velocity (r = 0.77, P < 0.001). Six infants were diagnosed with newly developed or persistent pulmonary hypertension at 36 weeks postmenstrual age. Serial left ventricular eccentric index showed a significantly different increasing trend in the pulmonary hypertension group (change per day: +0.004; P = 0.090) from the decreasing trend among a non-pulmonary hypertension group (change per day: -0.001; P = 0.041) (P for interaction = 0.007). Right ventricular systolic function and right ventricular isovolumic systolic velocity revealed a reducing trend in the pulmonary hypertension group, which was different from the improving trend in non-pulmonary hypertension infants. Infants with low current weight, low postmenstrual age, and requiring high-flow oxygen therapy at day 28 of life trended to increase the risk of late pulmonary hypertension.

CONCLUSION

Left ventricular eccentric index and right ventricular isovolumic systolic velocity were feasible for assessing pulmonary hypertension and should be incorporated into pulmonary hypertension evaluation. Serial left ventricular eccentric index and right ventricular isovolumic systolic velocity may help predict late pulmonary hypertension and early detection of right ventricular dysfunction.

Clinical Characteristics and Outcomes of SARS-CoV-2 Infection in Neonates with Persistent Pulmonary Hypertension of the Newborn (PPHN): A Systematic Review

PPHN is a common cause of neonatal respiratory failure and is still a serious condition that is associated with high mortality.

OBJECTIVES

To analyze the clinical characteristics and outcomes of SARS-CoV-2 infection in neonates with PPHN to identify neonatal cases at risk to develop severe illness.

METHODS

For this systematic review, we adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and searched Medline, Embase, CINAHL, and PubMed for studies on the development of COVID-19 in neonates with PPHN, published from 1 December 2019 to 29 February 2024, with an English language restriction.

RESULTS

Of the 2406 papers that were identified, 21 articles were included in the systematic review. Studies involving thirty-six neonates with PPHN and infected with SARS-CoV-2 were analyzed (twenty-nine survived, six died, and one is still hospitalized). The main causes of PPHN in neonates who had COVID-19 were neonatal respiratory distress syndrome (NRDS) (41.7%), meconium-stained amniotic fluid (MSAF) (16.7%), preterm premature rupture of membranes (PPROM) (11.1%), hypoxic ischemic encephalopathy (HIE) (5.5%), pneumonia (5.5%), and idiopathic (2.8%). Most of those neonates were male (33.3%), belonged to Indian ethnicity (50%), and were delivered via caesarean section (44.4%). COVID-19 in cases with PPHN commonly occurred in neonates born with a pregnancy range from 32 to <37 weeks (moderate to late preterm) (36.1%). The maternal severity of COVID-19 was reported to be severe in three cases only (8.3%); however, SARS-CoV-2 infection in neonates with PPHN was either severe (44.4%) or critical (22.2%). Most of these neonates experienced acute respiratory distress syndrome (ARDS) (58.3%). Early and late multisystem inflammatory syndrome in neonates (MIS-N) were reported in 50% and 11.1%, respectively. A high proportion of neonates were admitted to the intensive care unit (ICU) (58.3%) or needed mechanical ventilation (MV) (47.2%). Neonates with concurrent PPHN and SARS-CoV-2 infection who died had worse severity of COVID-19 [i.e., severity of COVID-19 was critical in 10% (neonates with PPHN who survived group) vs. 83.3% (neonates with PPHN who died group); p = 0.026]. Neonates with PPHN and COVID-19 had a higher relative risk of death if they received more antibiotics (RR 4.14, 95% CI 0.64-6.88) and if their COVID-19 was defined as critical (RR 2.84, 95% CI 0.86-9.39). Male neonates with PPHN and COVID-19 (RR 2.60, 95% CI 0.30-1.17) and those requiring prolonged invasive positive pressure ventilation (RR 2.22, 95% CI 0.64-7.73) also showed an increased relative risk for death.

CONCLUSIONS

COVID-19 in neonates with PPHN is challenging and may be associated with increased mortality, severity, ICU admission, ARDS, MIS-N, and MV usage. The results should be interpreted with caution owing to the small number of studies and substantial heterogeneity and indicate a need for future research in this area. Due to its benefits, testing for SARS-CoV-2 should be encouraged for newborns with symptoms consistent with COVID-19, especially in neonates with a history of SARS-CoV-2 exposure. Effective protection measures should be implemented during delivery and post-delivery care as necessary.

Patent ductus arteriosus and the association between lung ultrasound score and bronchopulmonary dysplasia: a secondary analysis of a prospective study

Moderate-to-large patent ductus arteriosus (PDA) has been linked to increased risk of bronchopulmonary dysplasia (BPD), while lung ultrasound score (LUS) has been demonstrated to accurately predict BPD. We aimed to investigate the correlation of LUS as a marker of interstitial pulmonary edema and the severity of the ductal shunt in predicting future BPD development in very preterm infants. This secondary analysis of a prospective study recruited preterm infants with gestational age < 30 weeks. LUS on postnatal days 7 and 14, and echocardiographic data [PDA diameter and left atrium-to-aortic root ratio (LA/Ao)] near LUS acquisition were collected. Correlation coefficient, logistics regression analysis, and the area under the receiver operating characteristic (AUROC) procedure were used. A statistically significant and positive correlation existed between LUS and PDA diameter (ρ = 0.415, ρ = 0.581, and p < 0.001) and LA/Ao (ρ = 0.502, ρ = 0.743, and p < 0.001) at postnatal days 7 and 14, respectively, and the correlations of LUS and echocardiographic data were generally stronger in the non-BPD group. In the prediction of BPD, LUS incorporating echocardiographic data at postnatal days 7 obtained significantly higher predictive performance compared to LUS alone (AUROC 0.878 [95% CI 0.801-0.932] vs. AUROC 0.793 [95% CI 0.706-0.865]; Delong test, p = 0.013).

CONCLUSIONS

There is a statistically significant correlation between LUS and echocardiographic data, suggesting their potential role as early predictors for respiratory outcomes in very preterm infants.

WHAT IS KNOWN

• Lung ultrasound score (LUS) has shown good reliability in predicting bronchopulmonary dysplasia (BPD) development. • Some echocardiographic data that characterized ventricular function was reported to be used to predict severe BPD.

WHAT IS NEW

• There is a positive and statistically significant correlation between LUS and echocardiographic data at postnatal days 7 and 14. • The integrated use of LUS and echocardiographic data may have potential value in predicting BPD.

Neonatal outcomes of preterm infants with pulmonary hypertension: clustering based on prenatal risk factors

BACKGROUND

To investigate association of prenatal risk factors and neonatal outcomes of preterm infants with pulmonary hypertension (PH).

METHODS

A prospective cohort study of very-low-birth-weight infants born at 22-29 weeks' gestation who received PH-specific treatment during hospitalization. Infants were classified using a two-step cluster analysis based on gestational age (GA), small-for-gestational-age (SGA), exposure to antenatal corticosteroids (ACS), histologic chorioamnionitis (HCA), and oligohydramnios.

RESULTS

Among 910 infants, six clusters were identified: cluster A (HCA, n = 240), cluster B (oligohydramnios, n = 79), cluster C (SGA, n = 74), cluster D (no-ACS, n = 109), cluster E (no dominant parameter, n = 287), and cluster F (HCA and oligohydroamnios, n = 121). Cluster A was used as a reference group for comparisons among clusters. Compared to cluster A, cluster C (aHR: 1.63 [95% CI: 1.17-2.26]) had higher risk of overall in-hospital mortality. Clusters B (aHR: 1.52 [95% CI: 1.09-2.11]), D (aHR: 1.71 [95% CI: 1.28-2.30]), and F (aHR: 1.51 [95% CI: 1.12-2.03]) had higher risks of receiving PH-specific treatment within the first week of birth compared to cluster A.

CONCLUSION

These findings may provide a better understanding of prenatal risk factors contributing to the development of PH.

IMPACT

Pulmonary hypertension (PH), presenting as hypoxic respiratory failure, has complex etiologies in preterm infants. Although multifactorial risks for the development of PH in preterm infants are known, few studies have classified infants with similar etiologies for PH. Each cluster has distinct patterns of prenatal condition and neonatal outcome.

Studying the Pulmonary Endothelium in Health and Disease: An Official American Thoracic Society Workshop Report

Lung endothelium resides at the interface between the circulation and the underlying tissue, where it senses biochemical and mechanical properties of both the blood as it flows through the vascular circuit and the vessel wall. The endothelium performs the bidirectional signaling between the blood and tissue compartments that is necessary to maintain homeostasis while physically separating both, facilitating a tightly regulated exchange of water, solutes, cells, and signals. Disruption in endothelial function contributes to vascular disease, which can manifest in discrete vascular locations along the artery-to-capillary-to-vein axis. Although our understanding of mechanisms that contribute to endothelial cell injury and repair in acute and chronic vascular disease have advanced, pathophysiological mechanisms that underlie site-specific vascular disease remain incompletely understood. In an effort to improve the translatability of mechanistic studies of the endothelium, the American Thoracic Society convened a workshop to optimize rigor, reproducibility, and translation of discovery to advance our understanding of endothelial cell function in health and disease.

Elevated pulmonary capillary wedge pressure, higher blood pressure, and lower cardiac index in infants with bronchopulmonary dysplasia

BACKGROUND

Left ventricular diastolic dysfunction indicated by elevated pulmonary capillary wedge pressure (ePCWP) may worsen cardiorespiratory status in bronchopulmonary dysplasia (BPD), but the scope of ePCWP by cardiac catheterization is not well described.

METHODS

This single-center retrospective cohort study included infants with BPD without congenital heart disease, significant intracardiac shunts, or pulmonary vein stenosis who underwent cardiac catheterization from 2010 to 2021. ePCWP was defined as >10 mmHg. Quantitative measures of ventricular systolic and diastolic function were performed on existing echocardiograms. Patients with and without ePCWP were compared using the Chi-squared or Wilcoxon rank-sum tests. Associations between catheterization hemodynamics and echocardiographic parameters were assessed by simple linear regression.

RESULTS

Seventy-one infants (93% Grade 2 or 3 BPD) met inclusion criteria, and 30 (42%) had ePCWP. Patients with ePCWP were older at catheterization (6.7 vs. 4.5 months, p < 0.001), more commonly underwent tracheostomy (66.7% vs. 29.3%, p = 0.003), and had higher mean systemic blood pressure [64.5 (56.0, 75.0) vs. 47.0 (43.0, 55.0) mm Hg, p < 0.001], higher systemic vascular resistance [11.9 (10.4, 15.6) vs. 8.7 (6.7, 11.2) WU*m2, p < 0.001), and lower cardiac index [3.9 (3.8, 4.9) vs. 4.7 (4.0, 6.3) L/min/m2, p = 0.03] at catheterization. Mean pulmonary artery pressure, pulmonary vascular resistance, and mortality were similar between the groups. Echocardiographic indices of left ventricular diastolic dysfunction did not correlate with PCWP.

CONCLUSIONS

ePCWP was common in infants with severe BPD who underwent cardiac catheterization in this cohort. The association between ePCWP and higher systemic blood pressure supports further study of afterload reduction in this population.

An interdisciplinary consensus approach to pulmonary hypertension in developmental lung disease

It is increasingly recognised that diverse genetic respiratory disorders present as severe pulmonary hypertension (PH) in the neonate and young infant, but many controversies and uncertainties persist regarding optimal strategies for diagnosis and management to maximise long-term outcomes. To better define the nature of PH in the setting of developmental lung disease (DEVLD), in addition to the common diagnoses of bronchopulmonary dysplasia and congenital diaphragmatic hernia, we established a multidisciplinary group of expert clinicians from stakeholder paediatric specialties to highlight current challenges and recommendations for clinical approaches, as well as counselling and support of families. In this review, we characterise clinical features of infants with DEVLD/DEVLD-PH and identify decision-making challenges including genetic evaluations, the role of lung biopsies, the use of imaging modalities and treatment approaches. The importance of working with team members from multiple disciplines, enhancing communication and providing sufficient counselling services for families is emphasised to create an interdisciplinary consensus.

International treatment outcomes of neonates on extracorporeal membrane oxygenation (ECMO) with persistent pulmonary hypertension of the newborn (PPHN): a systematic review

BACKGROUND

PPHN is a common cause of neonatal respiratory failure and is still a serious condition and associated with high mortality.

OBJECTIVES

To compare the demographic variables, clinical characteristics, and treatment outcomes in neonates with PHHN who underwent ECMO and survived compared to neonates with PHHN who underwent ECMO and died.

METHODS

We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline and searched ProQuest, Medline, Embase, PubMed, CINAHL, Wiley online library, Scopus and Nature for studies on the development of PPHN in neonates who underwent ECMO, published from January 1, 2010 to May 31, 2023, with English language restriction.

RESULTS

Of the 5689 papers that were identified, 134 articles were included in the systematic review. Studies involving 1814 neonates with PPHN who were placed on ECMO were analyzed (1218 survived and 594 died). Neonates in the PPHN group who died had lower proportion of normal spontaneous vaginal delivery (6.4% vs 1.8%; p value > 0.05) and lower Apgar scores at 1 min and 5 min [i.e., low Apgar score: 1.5% vs 0.5%, moderately abnormal Apgar score: 10.3% vs 1.2% and reassuring Apgar score: 4% vs 2.3%; p value = 0.039] compared to those who survived. Neonates who had PPHN and died had higher proportion of medical comorbidities such as omphalocele (0.7% vs 4.7%), systemic hypotension (1% vs 2.5%), infection with Herpes simplex virus (0.4% vs 2.2%) or Bordetella pertussis (0.7% vs 2%); p = 0.042. Neonates with PPHN in the death group were more likely to present due to congenital diaphragmatic hernia (25.5% vs 47.3%), neonatal respiratory distress syndrome (4.2% vs 13.5%), meconium aspiration syndrome (8% vs 12.1%), pneumonia (1.6% vs 8.4%), sepsis (1.5% vs 8.2%) and alveolar capillary dysplasia with misalignment of pulmonary veins (0.1% vs 4.4%); p = 0.019. Neonates with PPHN who died needed a longer median time of mechanical ventilation (15 days, IQR 10 to 27 vs. 10 days, IQR 7 to 28; p = 0.024) and ECMO use (9.2 days, IQR 3.9 to 13.5 vs. 6 days, IQR 3 to 12.5; p = 0.033), and a shorter median duration of hospital stay (23 days, IQR 12.5 to 46 vs. 58.5 days, IQR 28.2 to 60.7; p = 0.000) compared to the neonates with PPHN who survived. ECMO-related complications such as chylothorax (1% vs 2.7%), intracranial bleeding (1.2% vs 1.7%) and catheter-related infections (0% vs 0.3%) were more frequent in the group of neonates with PPHN who died (p = 0.031).

CONCLUSION

ECMO in the neonates with PPHN who failed supportive cardiorespiratory care and conventional therapies has been successfully utilized with a neonatal survival rate of 67.1%. Mortality in neonates with PPHN who underwent ECMO was highest in cases born via the caesarean delivery mode or neonates who had lower Apgar scores at birth. Fatality rate in neonates with PPHN who underwent ECMO was the highest in patients with higher rate of specific medical comorbidities (omphalocele, systemic hypotension and infection with Herpes simplex virus or Bordetella pertussis) or cases who had PPHN due to higher rate of specific etiologies (congenital diaphragmatic hernia, neonatal respiratory distress syndrome and meconium aspiration syndrome). Neonates with PPHN who died may need a longer time of mechanical ventilation and ECMO use and a shorter duration of hospital stay; and may experience higher frequency of ECMO-related complications (chylothorax, intracranial bleeding and catheter-related infections) in comparison with the neonates with PPHN who survived.

Patent Ductus Arteriosus and Lung Magnetic Resonance Imaging Phenotype in Moderate and Severe Bronchopulmonary Dysplasia-Pulmonary Hypertension

Rationale: Hemodynamically significant patent ductus arteriosus (hsPDA) in premature infants has been associated with bronchopulmonary dysplasia (BPD) and pulmonary hypertension (PH). However, these associations remain incompletely understood. Objectives: To assess the associations between hsPDA duration and clinical outcomes, PH, and phenotypic differences on lung magnetic resonance imaging (MRI). Methods: In this retrospective cohort study, we identified all infants with BPD at <32 weeks' gestation who also underwent research lung MRI at <48 weeks' postmenstrual age (PMA) from 2014 to 2022. Clinical echocardiograms were reviewed for hsPDA and categorized as no hsPDA, hsPDA 1-60 days, and hsPDA >60 days. Outcome variables included BPD severity, PH at 36 weeks' PMA, PH after 36 weeks' PMA in the absence of shunt (PH-pulmonary vascular disease [PVD]), tracheostomy or death, and lung phenotype by MRI via modified Ochiai score, indexed total lung volume, and whole-lung hyperdensity. Logistic regression and ANOVA were used. Measurements and Main Results: In total, 133 infants born at 26.2 ± 1.9 weeks, weighing 776 ± 276 g, were reviewed (47 with no hsPDA, 44 with hsPDA 1-60 days, and 42 with hsPDA >60 d). hsPDA duration > 60 days was associated with BPD severity (P < 0.01), PH at 36 weeks' PMA (adjusted odds ratio [aOR], 9.7 [95% confidence interval (CI), 3.3-28.4]), PH-PVD (aOR, 6.5 [95% CI, 2.3-18.3]), and tracheostomy or death (aOR, 3.0 [95% CI, 1.0-8.8]). Duration of hsPDA > 60 days was associated with higher Ochiai score (P = 0.03) and indexed total lung volume (P = 0.01) but not whole-lung hyperdensity (P = 0.91). Conclusions: In infants with moderate or severe BPD, prolonged exposure to hsPDA is associated with BPD severity, PH-PVD, and increased parenchymal lung disease by MRI.

Cardiovascular Sequelae of Bronchopulmonary Dysplasia in Preterm Neonates Born before 32 Weeks of Gestational Age: Impact of Associated Pulmonary and Systemic Hypertension

Bronchopulmonary dysplasia (BPD) remains the most common respiratory disorder of prematurity for infants born before 32 weeks of gestational age (GA). Early and prolonged exposure to chronic hypoxia and inflammation induces pulmonary hypertension (PH) with the characteristic features of a reduced number and increased muscularisation of the pulmonary arteries resulting in an increase in the pulmonary vascular resistance (PVR) and a fall in their compliance. BPD and BPD-associated pulmonary hypertension (BPD-PH) together with systemic hypertension (sHTN) are chronic cardiopulmonary disorders which result in an increased mortality and long-term problems for these infants. Previous studies have predominantly focused on the pulmonary circulation (right ventricle and its function) and developing management strategies accordingly for BPD-PH. However, recent work has drawn attention to the importance of the left-sided cardiac function and its impact on BPD in a subset of infants arising from a unique pathophysiology termed postcapillary PH. BPD infants may have a mechanistic link arising from chronic inflammation, cytokines, oxidative stress, catecholamines, and renin-angiotensin system activation along with systemic arterial stiffness, all of which contribute to the development of BPD-sHTN. The focus for the treatment of BPD-PH has been improvement of the right heart function through pulmonary vasodilators. BPD-sHTN and a subset of postcapillary PH may benefit from afterload reducing agents such as angiotensin converting enzyme inhibitors. Preterm infants with BPD-PH are at risk of later cardiac and respiratory morbidities as young adults. This paper reviews the current knowledge of the pathophysiology, diagnosis, and treatment of BPD-PH and BPD-sHTN. Current knowledge gaps and emerging new therapies will also be discussed.

Clinical phenotype of pulmonary vascular disease requiring treatment in extremely preterm infants

BACKGROUND

Pulmonary vascular disease (PVD) and pulmonary hypertension (PH) is a significant disorder affecting prognosis of extremely preterm infants. However, there is still a lack of a consensus on the definition and optimal treatments of PH, and there is also a lack of research comparing these conditions with persistent pulmonary hypertension of newborn (PPHN), early PH, and late PH. To investigate PH in extremely preterm infants, this study compared the baseline characteristics, short-term outcomes, and treatment duration, categorized by the timing of requiring PH treatment.

METHODS

This study retrospectively analyzed extremely preterm infants admitted to a single tertiary center. Between 2018 and 2022, infants with clinical or echocardiographic diagnosis of PH who required treatment were divided into three groups based on the timing of treatment initiation: initial 3 days (extremely early-period), from day 4 to day 27 (early-period), and after day 28 (late-period). The study compared the outcomes, including mortality rates, bronchopulmonary dysplasia (BPD) severity, PH treatment duration, and oxygen therapy duration, among the three groups.

RESULTS

Among the 157 infants, 67 (42.7%) were treated for PH during their stay. Of these, 39 (57.3%) were treatment in extremely early, 21 (31.3%) in early, and seven (11.4%) in late periods. No significant differences were observed in maternal factors, neonatal factors, or morbidity between the three groups. However, infants who received extremely early-period treatment had a higher mortality rate, but shorter duration of noninvasive respiratory support, oxygen therapy, and PH medication use. On the other hand, the late-period treatment group received longer durations of respiratory support and treatment.

CONCLUSIONS

This study revealed differences in mortality rates, respiratory outcomes, and treatment duration between the three groups, suggesting varying pathophysiologies over time in extremely preterm infants.

Association of cord blood Ang-1 and sCD105 levels with bronchopulmonary dysplasia in preterm infants

BACKGROUND

To investigate the relationship between cord blood levels of Angiopoietin-1 (Ang-1) and S-endoglin (sCD105) and bronchopulmonary dysplasia (BPD) in preterm infants.

METHODS

Sixty-one preterm infants admitted to the neonatal intensive care unit of the study hospital between July 2021 and September 2022 were included. Cord blood was collected after the birth of premature infants. Ang-1 and sCD105 levels were quantified using the vascular endothelial growth factor enzyme-linked immunosorbent assay. Preterm infants were divided into BPD and non-BPD groups, and differences in Ang-1 and sCD105 levels between the two groups were compared. A binary logistic model was used to assess the association between low and high levels Ang-1 and BPD in preterm infants.

RESULTS

In the study, there were 20 preterm infants with BPD (32.8%) and 41 preterm infants with non-BPD (67.2%). Ang-1 concentration levels were lower in the BPD group than in the non-BPD group (7105.43 (5617.01-8523.00) pg/ml vs. 10488.03 (7946.19-15962.77) pg/ml, P = 0.027). However, the sCD105 concentration levels were not significantly different between the BPD and non-BPD groups (P = 0.246). A median Ang-1 concentration of 8800.40 pg/ml was calculated. Logistic regression analysis showed that after adjusting for gestational age, birth weight, and maternal prenatal steroid hormone application, the odds ratio (OR) was 8.577 for the risk of BPD in preterm infants with Ang-1 concentrations of ≤ 8800.40 pg/ml compared to those with Ang-1 concentrations of > 8800.40 pg/ml (OR: 8.577, 95% confidence interval: 1.265-58.155, P = 0.028).

CONCLUSION

Our study indicated that Ang-1 levels in the cord blood of preterm infants may be associated the risk of BPD. In the future, we will continue to conduct study with large samples.

Assessing the role of tracheostomy placement in bronchopulmonary dysplasia with pulmonary hypertension

OBJECTIVE

Bronchopulmonary dysplasia (BPD) is a common complication of preterm birth and is associated with abnormal vasculature that contributes to pulmonary hypertension (PH). We evaluated how a tracheostomy may alter PH in these patients.

METHODS

A retrospective chart review over 15-years identified 17 patients with BPD and PH who underwent tracheostomy. Each patient had four echocardiograms re-reviewed and scored for tricuspid valve regurgitation velocity (TR), tricuspid annular plane systolic excursion (TAPSE), right atrial cross-sectional area (RACA), and left ventricle eccentricity indices (EI).

RESULT

There was improvement in TR, TAPSE, RACA, and left ventricle EI indicating reduction in PH after tracheostomy.

CONCLUSION

PH improves over time though role of tracheostomy in PH needs to be further defined. The EI may be a sensitive marker to follow over time in these patients.

The relationship between severe hypertensive diseases of pregnancy and moderate-severe bronchopulmonary dysplasia

OBJECTIVE

Determine the association between severe hypertensive disease of pregnancy (HDP) with moderate-severe bronchopulmonary dysplasia (BPD) in preterm infants (< 31 weeks' gestation).

STUDY DESIGN

Preterm birth cohort study of 693 mother-infant dyads. Severe HDP was defined as severe preeclampsia, HELLP syndrome or eclampsia. The outcome was moderate-severe BPD classified at 36 weeks corrected gestational age, per the NICHD Consensus statement.

RESULTS

225 (32%) mothers developed severe HDP and 234 (34%) infants had moderate-severe BPD. There was an interaction between severe HDP and gestational age (p = 0.03). Infants born at < 25 weeks gestation to mothers with HDP had increased odds for moderate-severe BPD compared to infants of normotensive mothers delivering at the same gestational age. Infants born > 28 weeks to mothers with severe HDP had decreased odds for the outcome, though not statistically significant.

CONCLUSIONS

Severe HDP has a differential effect on the development of moderate-severe BPD based on gestational age.

Bronchopulmonary Dysplasia-Associated Pulmonary Hypertension: Basing Care on Physiology

Bronchopulmonary dysplasia (BPD) is the heterogeneous chronic lung developmental disease of prematurity, which is often accompanied by multisystem comorbidities. Pulmonary vascular disease and pulmonary hypertension (PH) contribute significantly to the pathogenesis and pathophysiology of BPD and dramatically influence the outcomes of preterm infants with BPD. When caring for those patients, clinicians should consider the multitude of phenotypic presentations that fall under the "BPD-PH umbrella," reflecting the need for matching therapies to specific physiologies to improve short- and long-term outcomes. Individualized management based on the patient's prenatal and postnatal risk factors, clinical course, and cardiopulmonary phenotype needs to be identified and prioritized to provide optimal care for infants with BPD-PH.

Right ventricular function indices and platelet parameters for early prediction value of bronchopulmonary dysplasia: a retrospective study

BACKGROUND

To examine the value of early echocardiographic indices for the right ventricular function combined with platelet(PLT) parameters for predicting bronchopulmonary dysplasia (BPD) in preterm infants.

METHODS

This retrospective study included infants with gestational age (GA) below 32 weeks, who were admitted to the neonatal intensive care unit(NICU). The detection rate of tricuspid regurgitation jet velocity (TRVJ), ventricular septal flattening, pulmonary artery widening, right ventricular dilation, and right atrial enlargement on the 7th day of life (DOL 7) were compared between BPD and non-BPD infants. Echocardiographic indices of the right ventricular function including tricuspid annular plane systolic excursion (TAPSE) and right ventricular index of myocardial performance (RIMP) were measured on 1 day of life (DOL 1)、on DOL 7 and on 14 day of life (DOL 14) respectively. The PLT parameters including the PLT count, mean platelet volume (MPV), platelet hematocrit (PCT) level, and platelet distribution width (PDW) were measured on the DOL 1,DOL 7, and DOL 14. Multivariate logistic regression was used to analyze the relationship between these parameters and BPD. Receiver operating characteristic curve analysis was performed to assess the predictive value of the right ventricular function indices and PLT parameters for BPD.

RESULTS

A total of 220 preterm infants were included in this study, and of these, 85 infants developed BPD among them. The RIMP of the BPD group on DOL 14 was higher than that of the non-BPD group (P < 0.05). The TAPSE of the BPD group on DOL 14 was lower than that of the non-BPD group (P < 0.05). The PLT count of the BPD group on DOL 1 was lower than that of the non-BPD group (P < 0.05), and the MPV of the BPD group on DOL 1 was higher than that of the non-BPD group (P < 0.05). Using multivariate logistic regression, GA、invasive mechanical ventilation duration ≥ 7 days、 PLT、 MPV、 TAPSE and RIMP were found to be independent risk factors for BPD. The area under the receiver operating characteristic curve was 0.846 (95CI: 0.794∼0.899), which improved when using right ventricular function indices combined with platelet parameters.

CONCLUSION

TAPSE and RIMP combined with PLT count and MPV can help identify preterm infants at an increased risk of developing BPD.

Navigating Diagnostic and Treatment Challenges of Pulmonary Hypertension in Infants with Bronchopulmonary Dysplasia

Advances in perinatal intensive care have significantly enhanced the survival rates of extremely low gestation-al-age neonates but with continued high rates of bronchopulmonary dysplasia (BPD). Nevertheless, as the survival of these infants improves, there is a growing awareness of associated abnormalities in pulmonary vascular development and hemodynamics within the pulmonary circulation. Premature infants, now born as early as 22 weeks, face heightened risks of adverse development in both pulmonary arterial and venous systems. This risk is compounded by parenchymal and airway abnormalities, as well as factors such as inflammation, fibrosis, and adverse growth trajectory. The presence of pulmonary hypertension in bronchopulmonary dysplasia (BPD-PH) has been linked to an increased mortality and substantial morbidities, including a greater susceptibility to later neurodevelopmental challenges. BPD-PH is now recognized to be a spectrum of disease, with a multifactorial pathophysiology. This review discusses the challenges associated with the identification and management of BPD-PH, both of which are important in minimizing further disease progression and improving cardiopulmonary morbidity in the BPD infant.

Bosentan in the treatment of persistent pulmonary hypertension in newborns: a systematic review and meta-analysis

BACKGROUND

Persistent pulmonary hypertension of the newborn is a life-threatening condition that affects about 1-2 per 1,000 live births worldwide. Bosentan is an oral dual endothelin receptor antagonist that may have a beneficial effect on persistent pulmonary hypertension of the newborn by reducing pulmonary vascular resistance and improving oxygenation. However, its role in persistent pulmonary hypertension of the newborn remains unclear.

OBJECTIVES

To systematically evaluate the efficacy and safety of bosentan as an adjuvant therapy for persistent pulmonary hypertension of the newborn in newborns.

METHODS

We searched six English and two Chinese databases from their inception to 1 January 2023 following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We included randomised controlled trials and retrospective studies that compared bosentan with placebo or other drugs for persistent pulmonary hypertension of the newborn in newborns. We performed a meta-analysis using random-effects models and assessed the risk of bias and heterogeneity in the included studies.

RESULTS

We included 10 studies with a total of 550 participants. Bosentan significantly reduced the treatment failure rate (relative risk = 0.25, P < 0.001), pulmonary artery pressure (mean difference = -11.79, P < 0.001), and length of hospital stay (mean difference = -1.04, P = 0.003), and increased the partial pressure of oxygen (mean difference = 10.02, P < 0.001) and blood oxygen saturation (SpO2) (mean difference = 8.24, P < 0.001) compared with a placebo or other drugs. The occurrence of adverse reactions was not significantly different between bosentan and a placebo or other drugs.

CONCLUSIONS

Bosentan is effective in the treatment of persistent pulmonary hypertension of the newborn but adverse reactions such as abnormal liver function should be observed when using it.

A comprehensive study on machine learning models combining with oversampling for bronchopulmonary dysplasia-associated pulmonary hypertension in very preterm infants

BACKGROUND

Bronchopulmonary dysplasia-associated pulmonary hypertension (BPD-PH) remains a devastating clinical complication seriously affecting the therapeutic outcome of preterm infants. Hence, early prevention and timely diagnosis prior to pathological change is the key to reducing morbidity and improving prognosis. Our primary objective is to utilize machine learning techniques to build predictive models that could accurately identify BPD infants at risk of developing PH.

METHODS

The data utilized in this study were collected from neonatology departments of four tertiary-level hospitals in China. To address the issue of imbalanced data, oversampling algorithms synthetic minority over-sampling technique (SMOTE) was applied to improve the model.

RESULTS

Seven hundred sixty one clinical records were collected in our study. Following data pre-processing and feature selection, 5 of the 46 features were used to build models, including duration of invasive respiratory support (day), the severity of BPD, ventilator-associated pneumonia, pulmonary hemorrhage, and early-onset PH. Four machine learning models were applied to predictive learning, and after comprehensive selection a model was ultimately selected. The model achieved 93.8% sensitivity, 85.0% accuracy, and 0.933 AUC. A score of the logistic regression formula greater than 0 was identified as a warning sign of BPD-PH.

CONCLUSIONS

We comprehensively compared different machine learning models and ultimately obtained a good prognosis model which was sufficient to support pediatric clinicians to make early diagnosis and formulate a better treatment plan for pediatric patients with BPD-PH.

Pulmonary Hypertension and Necrotizing Enterocolitis in Neonates Treated with Diazoxide

OBJECTIVE

This study aimed to evaluate the prevalence of adverse outcomes, specifically pulmonary hypertension (PH) and suspected or confirmed necrotizing enterocolitis (NEC), and their associated risk factors, in neonates treated with diazoxide.

STUDY DESIGN

A retrospective study in infants born ≥ 316/7 weeks and admitted between January 2014 and June 2020. Combined adverse outcomes possibly associated to diazoxide were PH (systolic pulmonary pressure of ≥40 mm Hg or an eccentricity index ≥1.3) and suspected or confirmed NEC (suspected: stop feeds and antibiotics and confirmed: modified Bell stage ≥2). Echocardiography data extractors were masked to infants' characteristics.

RESULTS

A total of 63 infants were included; 7 (11%) with suspected and 1 (2%) with confirmed NEC. Of the 36 infants with an available echocardiography after initiation of diazoxide treatment, 12 (33%) had PH. All infants with suspected or confirmed NEC were males (p = 0.01), whereas PH occurred mostly in females (75%, p = 0.02). The combined adverse outcome occurred in 14/26 (54%) infants exposed to >10 mg/kg/day, compared to 6/37 (16%) exposed to ≤10 mg/kg/day (p = 0.006). This association remained significant after adjustment for sex, small for gestational age status, and gestational age at birth (odds ratio: 6.1, 95% confidence interval: 1.7-21.7, p = 0.005). Left ventricular dysfunction was found in 19 infants (30%) but was not discriminative for the combined outcome.

CONCLUSION

PH and suspected or confirmed NEC were identified frequently in neonates treated with diazoxide. A total dose >10 mg/kg/day was associated with an increased occurrence of these complications.

KEY POINTS

· PH and suspected or confirmed NEC were frequently found in neonates treated with diazoxide.. · A total dose >10 mg/kg/day was associated with an increased occurrence of these complications.. · Echocardiography screening should be considered in neonates exposed to diazoxide..

Improving early diagnosis of bronchopulmonary dysplasia

INTRODUCTION

Bronchopulmonary disease (BPD) is associated with long-term neurodevelopmental and cardiorespiratory complications, often requiring significant use of resources. To reduce this healthcare burden, it is essential that those at high risk of BPD are identified early so that strategies are introduced to prevent disease progression. Our aim was to discuss potential methods for improving early diagnosis in the first week after birth.

AREAS COVERED

A narrative review was undertaken. The search strategy involved searching PubMed, Embase and Cochrane databases from 1967 to 2024. The results of potential biomarkers and imaging modes are discussed. Furthermore, the value of scoring systems is explored.

EXPERT OPINION

BPD occurs as a result of disruption to pulmonary vascular and alveolar development, thus abnormal levels of factors regulating those processes are promising avenues to explore with regard to early detection of high-risk infants. Data from twin studies suggests genetic factors can be attributed to 82% of the observed difference in moderate to severe BPD, but large genome-wide studies have yielded conflicting results. Comparative studies are required to determine which biomarker or imaging mode may most accurately diagnose early BPD development. Models which include the most predictive factors should be evaluated going forward.

Delineating morbidity patterns in preterm infants at near-term age using a data-driven approach

BACKGROUND

Long-term survival after premature birth is significantly determined by development of morbidities, primarily affecting the cardio-respiratory or central nervous system. Existing studies are limited to pairwise morbidity associations, thereby lacking a holistic understanding of morbidity co-occurrence and respective risk profiles.

METHODS

Our study, for the first time, aimed at delineating and characterizing morbidity profiles at near-term age and investigated the most prevalent morbidities in preterm infants: bronchopulmonary dysplasia (BPD), pulmonary hypertension (PH), mild cardiac defects, perinatal brain pathology and retinopathy of prematurity (ROP). For analysis, we employed two independent, prospective cohorts, comprising a total of 530 very preterm infants: AIRR ("Attention to Infants at Respiratory Risks") and NEuroSIS ("Neonatal European Study of Inhaled Steroids"). Using a data-driven strategy, we successfully characterized morbidity profiles of preterm infants in a stepwise approach and (1) quantified pairwise morbidity correlations, (2) assessed the discriminatory power of BPD (complemented by imaging-based structural and functional lung phenotyping) in relation to these morbidities, (3) investigated collective co-occurrence patterns, and (4) identified infant subgroups who share similar morbidity profiles using machine learning techniques.

RESULTS

First, we showed that, in line with pathophysiologic understanding, BPD and ROP have the highest pairwise correlation, followed by BPD and PH as well as BPD and mild cardiac defects. Second, we revealed that BPD exhibits only limited capacity in discriminating morbidity occurrence, despite its prevalence and clinical indication as a driver of comorbidities. Further, we demonstrated that structural and functional lung phenotyping did not exhibit higher association with morbidity severity than BPD. Lastly, we identified patient clusters that share similar morbidity patterns using machine learning in AIRR (n=6 clusters) and NEuroSIS (n=8 clusters).

CONCLUSIONS

By capturing correlations as well as more complex morbidity relations, we provided a comprehensive characterization of morbidity profiles at discharge, linked to shared disease pathophysiology. Future studies could benefit from identifying risk profiles to thereby develop personalized monitoring strategies.

TRIAL REGISTRATION

AIRR: DRKS.de, DRKS00004600, 28/01/2013. NEuroSIS: ClinicalTrials.gov, NCT01035190, 18/12/2009.

Serial tissue Doppler imaging in the evaluation of bronchopulmonary dysplasia-associated pulmonary hypertension among extremely preterm infants: a prospective observational study

Objectives

To evaluate serial tissue Doppler cardiac imaging (TDI) in the evolution of bronchopulmonary dysplasia-associated pulmonary hypertension (BPD-PH) among extremely preterm infants.

Design

Prospective observational study.

Setting

Single-center, tertiary-level neonatal intensive care unit.

Patients

Infant born <28 weeks gestation.

Main outcome measures

Utility of TDI in the early diagnosis and prediction of BPD-PH and optimal timing for screening of BPD-PH.

Results

A total of 79 infants were included. Of them, 17 (23%) had BPD-PH. The mean gestational age was 25.9 ± 1.1 weeks, and mean birth weight was 830 ± 174 g. The BPD-PH group had a high incidence of hemodynamically significant patent ductus arteriosus (83% vs. 56%, p < 0.018), longer oxygen days (96.16 ± 68.09 vs. 59.35 ± 52.1, p < 0.008), and prolonged hospital stay (133.8 ± 45.9 vs. 106.5 ± 37.9 days, p < 0.005). The left ventricular eccentricity index (0.99 ± 0.1 vs. 1.1 ± 0.7, p < 0.01) and the ratio of acceleration time to right ventricular ejection time showed a statistically significant trend from 33 weeks (0.24 ± 0.05 vs. 0.28 ± 0.05, p < 0.05). At 33 weeks, the BPD-PH group showed prolonged isovolumetric contraction time (27.84 ± 5.5 vs. 22.77 ± 4, p < 0.001), prolonged isovolumetric relaxation time (40.3 ± 7.1 vs. 34.9 ± 5.3, p < 0.003), and abnormal myocardial performance index (0.39 ± 0.05 vs. 0.32 ± 0.03, p < 0.001). These differences persisted at 36 weeks after conceptional gestational age.

Conclusions

TDI parameters are sensitive in the early evolution of BPD-PH. Diagnostic accuracy can be increased by combining the TDI parameters with conventional echocardiographic parameters. BPD-PH can be recognizable as early as 33-34 weeks of gestation.

Types of home respiratory support in children with bronchopulmonary dysplasia and factors determining its duration: A scoping review

Bronchopulmonary dysplasia also known as chronic lung disease of prematurity has changed as a disease entity over the last five decades and children with "new bronchopulmonary dysplasia (BPD)" have better survival rates. This necessitates strategies to prevent severe BPD and provide organized home support. Home respiratory support in these children varies from home oxygen to noninvasive ventilation and tracheostomy ventilation. This review was conducted utilizing Joanna Briggs Institute publications on evidence synthesis and presentation of results for a scoping review. The Preferred Reporting Items for Systematic Review and Meta-Analyses were used to report the results. The risk of bias assessment was done using "The Cochrane Handbook for Systematic Reviews tool for interventional studies." After screening for the duplication of results and applying inclusion and exclusion criteria, twenty-seven studies were assessed by reading the full texts. Out of these, eleven were finally included in this systematic review. The total sample size from all studies was 4794, including 2705 males. The 4/11 studies home oxygen, one study reported continuous positive airway pressure/bilevel positive airway pressure and seven studies used tracheostomy or tracheostomy ventilation. The median duration of post-natal invasive ventilation was higher in those discharged on home oxygen compared to those who did not need oxygen at discharge. There is a significant proportion of children who are tracheostomy ventilated (8.65%) at home. In the absence of established guidelines, these children are vulnerable when it comes to care at home and the timing of decannulation. For home oxygen alone, guidelines by ERS, ATS and BTS have streamlined weaning protocols and the need for having a multi-disciplinary team to care for these children.

Hemodynamic Melody of Postnatal Cardiac and Pulmonary Development in Children with Congenital Heart Diseases

Hemodynamics is the eternal theme of the circulatory system. Abnormal hemodynamics and cardiac and pulmonary development intertwine to form the most important features of children with congenital heart diseases (CHDs), thus determining these children's long-term quality of life. Here, we review the varieties of hemodynamic abnormalities that exist in children with CHDs, the recently developed neonatal rodent models of CHDs, and the inspirations these models have brought us in the areas of cardiomyocyte proliferation and maturation, as well as in alveolar development. Furthermore, current limitations, future directions, and clinical decision making based on these inspirations are highlighted. Understanding how CHD-associated hemodynamic scenarios shape postnatal heart and lung development may provide a novel path to improving the long-term quality of life of children with CHDs, transplantation of stem cell-derived cardiomyocytes, and cardiac regeneration.

Factors in the Neonatal Period Associated With Pulmonary Hypertension at 28 Days of Life in Broncho-Pulmonary Dysplasia

Objectives. To identify factors associated with pulmonary hypertension (PH) at 28 days of life in preterm infants with bronchopulmonary dysplasia (BPD). Methods. This observational study included 128 premature infants with BPD between January 2022 and February 2023 from the neonatal intensive care unit of Vietnam National Children's Hospital. Results. PH was observed using echocardiography in 29 patients (22.66%). The prevalence of severe BPD in the PH group (62.07%) was significantly higher than that in the non-PH group (18.18%). The multivariate logistic regression showed 2 predictors of PH in BPD: invasive mechanical ventilation up to 28 days of life (odds ratio [OR]:9.440; 95% confidence interval [CI]: 3.090-28.833; P < .001) and history of shock (OR: 2.962; 95% CI: 1.067-8.225; P = .037). Conclusion. We found 2 predictors of PH at 28 days of life in BPD: invasive mechanical ventilation up to 28 days of life and history of shock.

Shape of Pulmonary Artery Doppler Flow Profile and Right Ventricular Hemodynamics in Neonates

OBJECTIVES

To characterize pulmonary artery Doppler flow profile (PAFP) patterns among infants receiving care in neonatal intensive care units and to examine the association of PAFP patterns with pulmonary and right ventricular (RV) hemodynamics.

STUDY DESIGN

This is a retrospective study at 2 tertiary intensive care units over 4 years that included neonates who demonstrated a complete tricuspid regurgitation envelope on targeted neonatal echocardiography. Separate personnel reviewed TNEs to characterize PAFP patterns, divide cohort into PAFP groups, and measure quantitative indices of RV hemodynamics (RV systolic pressure, pulmonary artery acceleration time and its ratio with RV ejection time, tricuspid annular plane systolic excursion, and RV output), for intergroup comparisons.

RESULTS

We evaluated TNEs from 186 neonates with median gestational age of 28.5 weeks (IQR, 25.9-35.9 weeks). Four distinct PAFP patterns were identified (A) near-isosceles triangle (22%), (B) right-angled triangle (29%), (C) notching (40%), and (D) low peak velocity (<0.4 m/s; 9%). Groups A-C demonstrated a stepwise worsening in all indices of PH, whereas pattern D was associated with lower tricuspid annular plane systolic excursion and RV output. Using common definitions of pulmonary hypertension (PH), pattern A performed best to rule out PH (sensitivity range, 81%-90%) and pattern C for diagnosing PH (specificity range, 63%-78%).

CONCLUSIONS

Inspection of PAFP is a simple bedside echocardiography measure that provides clinically meaningful information on underlying RV hemodynamics and may aid in screening and monitoring of patients for PH in intensive care units.

Targeted Neonatal Echocardiography in the Management of Neonatal Pulmonary Hypertension

Pulmonary hypertension (PH) in neonates, originating from a range of disease states with heterogeneous underlying pathophysiology, is associated with significant morbidity and mortality. Although the final common pathway is a state of high right ventricular afterload leading to compromised cardiac output, multiple hemodynamic phenotypes exist in acute and chronic PH, for which cardiorespiratory treatment strategies differ. Comprehensive appraisal of pulmonary pressure, pulmonary vascular resistance, cardiac function, pulmonary and systemic blood flow, and extrapulmonary shunts facilitates delivery of individualized cardiovascular therapies in affected newborns.

Pulmonary Hypertension in Established Bronchopulmonary Dysplasia: Physiologic Approaches to Clinical Care

Preterm infants with bronchopulmonary dysplasia (BPD) are prone to develop pulmonary hypertension (PH). Strong laboratory and clinical data suggest that antenatal factors, such as preeclampsia, chorioamnionitis, oligohydramnios, and placental dysfunction leading to fetal growth restriction, increase susceptibility for BPD-PH after premature birth. Echocardiogram metrics and serial assessments of NT-proBNP provide useful tools to diagnose and monitor clinical course during the management of BPD-PH, as well as monitoring for such complicating conditions as left ventricular diastolic dysfunction, shunt lesions, and pulmonary vein stenosis. Therapeutic strategies should include careful assessment and management of underlying airways and lung disease, cardiac performance, and systemic hemodynamics, prior to initiation of PH-targeted drug therapies.

Comorbidities and Late Outcomes in Neonatal Pulmonary Hypertension

Long-term outcomes of persistent pulmonary hypertension of newborn (PPHN) depend on disease severity, duration of ventilation, and associated anomalies. Congenital diaphragmatic hernia survivors may have respiratory morbidities and developmental delay. The presence of PPHN is associated with increased mortality in hypoxic-ischemic encephalopathy, though the effects on neurodevelopment are less clear. Preterm infants can develop pulmonary hypertension (PH) early in the postnatal course or later in the setting of bronchopulmonary dysplasia (BPD). BPD-PH is associated with higher mortality, particularly within the first year. Evidence suggests that both early and late PH in preterm infants are associated with neurodevelopmental impairment.

Pathogenesis and Physiologic Mechanisms of Neonatal Pulmonary Hypertension: Preclinical Studies

Neonatal pulmonary hypertension (PH) is a devastating disorder of the pulmonary vasculature characterized by elevated pulmonary vascular resistance and mean pulmonary arterial pressure. Occurring predominantly because of maldevelopment or maladaptation of the pulmonary vasculature, PH in neonates is associated with suboptimal short-term and long-term outcomes because its pathobiology is unclear in most circumstances, and it responds poorly to conventional pulmonary vasodilators. Understanding the pathogenesis and pathophysiology of neonatal PH can lead to novel strategies and precise therapies. The review is designed to achieve this goal by summarizing pulmonary vascular development and the pathogenesis and pathophysiology of PH associated with maladaptation, bronchopulmonary dysplasia, and congenital diaphragmatic hernia based on evidence predominantly from preclinical studies. We also discuss the pros and cons of and provide future directions for preclinical studies in neonatal PH.

Early Pulmonary Hypertension in Preterm Infants

Pulmonary hypertension (PH) in preterm neonates has multifactorial pathogenesis with unique characteristics. Premature surfactant-deficient lungs are injured following exposure to positive pressure ventilation and high oxygen concentrations resulting in variable phenotypes of PH. The prevalence of early PH is variable and reported to be between 8% and 55% of extremely preterm infants. Disruption of the lung development and vascular signaling pathway could lead to abnormal pulmonary vascular transition. The management of early PH and the off-label use of selective pulmonary vasodilators continue to be controversial.