Evaluation and Management of Pulmonary Hypertension in Children with Bronchopulmonary Dysplasia

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.

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.

Double-blind, non-inferiority, randomized controlled trial of dexamethasone 4, 5 and 6 mg for preventing adverse neonatal and maternal outcomes in very preterm to late preterm pregnancies between 29 0 and 36 6 weeks of gestation: study protocol

BACKGROUND

Premature birth poses significant health challenges, including respiratory distress syndrome (RDS). Corticosteroids reduce the incidence of RDS, but higher dexamethasone doses may lead to adverse neonatal outcomes, such as growth restriction and neurodevelopmental issues. Determining the appropriate dose is crucial to balance efficacy and safety. Dexamethasone is inexpensive and widely available in most low- and middle-income countries. This study aims to compare the efficacy and safety of 4-mg, 5-mg and 6-mg dexamethasone in preventing RDS among preterm infants. This trial aims to determine whether lower dexamethasone doses are as effective as the standard dose in preventing RDS in preterm infants. By assessing efficacy and potential adverse outcomes, this study will provide critical insights for optimizing treatment protocols and improving neonatal care.

METHODS

This randomized controlled trial will include pregnant women with gestational ages between 290 and 366 weeks admitted to Siriraj Hospital and three secondary centres in Thailand. The participants will be randomly assigned to receive intramuscular dexamethasone at 4 mg, 5 mg or 6 mg, which will be administered every 12 h for a total of four doses over 48 h. The same dose will be used for rescue or repeat courses. The primary outcome will be the incidence of RDS, defined by clinical criteria and confirmed by a neonatologist. The secondary outcomes will include other adverse neonatal and maternal outcomes.

RESULTS

The study requires 1,560 participants, accounting for a 15% loss to follow-up. The data will be analysed via descriptive statistics, chi-squared tests for categorical data, and one-way ANOVA or Kruskal-Wallis tests for continuous data. An independent Data Safety Monitoring Board will conduct interim analyses every 3 months to ensure participant safety and study integrity.

DISCUSSION

This trial addresses the gap in research regarding optimal dexamethasone dosing for preventing RDS in preterm infants. The study will provide evidence on whether lower doses of dexamethasone (4 and 5 mg) are as effective as the standard 6-mg dose and will examine their potential adverse outcomes. The results will guide adjustments to medical practice guidelines, aiming to align them with clinical practices while ensuring safety and efficacy. Trial registration page https://www.thaiclinicaltrials.org/export/pdf/TCTR20220511003 10/05/2022.

Characteristics associated with death or tracheostomy in infants with bronchopulmonary dysplasia following predominant non-invasive respiratory support

OBJECTIVE

Identify characteristics associated with death or tracheostomy (D/T) in preterm infants with bronchopulmonary dysplasia (BPD) predominantly managed with non-invasive respiratory support prior to 36 weeks postmenstrual age (PMA).

STUDY DESIGN

Retrospective cohort study at Children's Hospital of Philadelphia of 134 infants meeting inclusion criteria between 2010 and 2017. Various clinical characteristics were considered as predictor variables of the primary outcome, D/T; those associated at p < 0.10 in bivariable logistic regression were evaluated in multivariable models.

RESULTS

Twenty-one (16%) infants had D/T. Treatment with pulmonary vasodilators and the presence of pulmonary hypertension (PH) on echocardiogram at 36 weeks PMA were associated with D/T in bivariable analyses. Pulmonary vasodilator use remained statistically significant in adjusted multivariable models.

CONCLUSIONS

We identified a strong association between PH and D/T in this cohort. Our findings emphasize the importance of specialized BPD management that includes early identification of PH in this high-risk population.

Detection of pulmonary hypertension in preterm infants with bronchopulmonary dysplasia using oxygen saturation data

BACKGROUND

Pulmonary hypertension (PH) complicates the clinical course of bronchopulmonary dysplasia (BPD) in preterm infants, increasing risk of mortality and other morbidities. Early detection of PH may provide the clinical opportunity for earlier initiation of PH targeted therapies.

METHODS

We analyzed variability patterns of oxygen saturation data in 41 preterm infants with BPD and associated PH and 57 infants with BPD alone using irregularity indices to identify PH. Irregularity of oxygen saturation (SpO2) variability time series was characterized by sample entropy over multiple time scales, and characteristic features were derived. Multivariable logistic regression models with entropy-based indices and significant clinical risk factors as features were developed and their diagnostic accuracy metrics were evaluated.

RESULTS

SpO2 measures significantly differed between groups by PH status. The model with signal-based measures and clinical features of birthweight, sepsis, and presence of patent ductus arteriosus had discriminative ability for PH with 82% area under ROC (95% CI: 75%, 88%) and accuracy, sensitivity, and specificity of 81%, 78% and 82% respectively.

CONCLUSION

Irregularity profiles of oxygen saturation variability are distinct in infants with BPD and PH. Signal based measures derived from routinely collected SpO2 data can be leveraged as continuous bedside markers to detect PH in preterm infants.

IMPACT

Early detection of pulmonary hypertension (PH) may improve outcomes in infants with bronchopulmonary dysplasia (BPD). Bedside markers which can track evolving PH, using routinely collected data in the NICU are hence important. Analysis of the irregularity exhibited by oxygen saturation variability data from preterm infants with BPD identified distinctive behavior in the presence of PH. We demonstrated detection of PH using signal measures accounting for known clinical risk factors using data acquired prior to clinical diagnosis. This study expands the possibility of implementing signal based models for early identification of PH in this vulnerable population.

Modifiable and Non-Modifiable Risk Factors for Tracheostomy in Preterm Infants

OBJECTIVE

To identify risk factors for tracheostomy among infants born < 33 week gestational age.

METHODS

We conducted a retrospective matched case-control study of infants < 33 week gestation who underwent tracheostomy between 2000 and 2018 at a single level IV NICU. For each case, we identified two controls matched for gestational age ± 1 week and birthweight ± 100 g who were admitted during the same year. Records were reviewed for IMV duration, number of intubations/extubations, postnatal steroid exposure, BPD severity and other clinical factors. Odds ratios and 95% CI were calculated by a conditional logistic regression.

RESULTS

The mean (SD) gestation of the cohort (30 tracheostomy cases; 60 controls) was 26.2 (2.2) week. Tracheostomies were performed at 158 d (127-183) of age and 48 week (44.6-55) post-menstrual age (PMA) following 92 d (64-134) IMV; median (IQR). Tracheostomy was indicated for severe BPD [N = 19(68%)], acquired airway obstruction [N = 4(14%)], or severe BPD with airway obstruction [N = 5(18%)]. Additional risk factors included male sex, outborn birth, intrauterine growth retardation, pulmonary hypertension, and sepsis. IMV duration and length of stay were longer, postnatal steroid exposure was more common and PMA at discharge was later for tracheostomy cases than controls. The number of intubations, extubations (planned and unplanned) and extubations adjusted for IMV duration were significantly higher in cases than controls. In the final logistic model, the number of unplanned extubations and steroid courses were independently associated with tracheostomy.

CONCLUSION

Strategies to minimize tracheostomy risk should target modifiable risk factors such as reducing unplanned extubations and limiting postnatal steroids in high-risk infants.

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.

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 to 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 or SGA infants and late studies enrolling infants with early PV exposure or high-grade BPD would target current evidence gaps.

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.

The increased longitudinal basal-to-apical strain ratio in the right ventricular free wall is associated with neonatal pulmonary hypertension

It has been a challenging work to identify and assess neonatal pulmonary hypertension (PH). Right ventricular longitudinal strain (RVLS) is primarily used in evaluating right ventricular (RV) systolic function. This study aimed to investigate the association of the changes in segmental and global RVLS with neonatal PH, hoping to provide a new marker for indicating neonatal PH other than obtaining information on RV function. This was a cross-sectional study with 62 neonates, generally divided into PH and non-PH groups confirmed by echocardiography. For 30 infants later diagnosed with bronchopulmonary dysplasia (BPD), specific analysis was conducted by subdividing them into BPD with and without PH subgroups. Conventional echocardiography markers and the global and segmental RVLS were measured and compared. Their diagnostic performance in evaluating PH was analyzed. Regardless of grouping, the biventricular function of all infants was similar and in normal range. No significant difference was found in global strain parameters, either. In the case of PH, tricuspid regurgitant velocity (TRV), left ventricle systolic eccentricity index (LVsEI), and the basal-to-apical strain ratio (Ratio bas/api) of RV free wall (RVFW) were significantly higher (P < 0.001, P < 0.05, P < 0.05). By contrast, the magnitude of apical segmental strain reduced significantly (P < 0.05) and was significantly lower than that of basal segmental strain in BPD with PH subgroup (P = 0.024). The area under the curve values for Ratio bas/api was highest (0.846), followed by LVsEI (0.746) and apical segmental strain (0.272).

CONCLUSION

As a relatively standardized parameter, Ratio bas/api of RVFW was significantly higher in the case of neonatal PH with normal cardiac function and could be regarded as a new indicator for PH.

WHAT IS KNOWN

• It has been challenging work to diagnose neonatal pulmonary hypertension (PH), and conventional echocardiography has been widely applied, though it is not sufficient enough. • RV longitudinal strain (RVLS) is primarily used to assess RV systolic function, and its role in diagnosing PH was rarely considered.

WHAT IS NEW

• The basal-to-apical strain ratio (Ratio bas/api) of RV free wall increased significantly in all infants with PH regardless of causes. • As a relatively standardized parameter, Ratio bas/api could be regarded as a new indicator for diagnosing PH, apart from conventional echocardiographic parameters.

Correlating Severity of Pulmonary Hypertension by Echocardiogram with Mortality in Premature Infants with Bronchopulmonary Dysplasia

OBJECTIVE

 Bronchopulmonary dysplasia (BPD) is the most common complication of preterm birth. Infants with BPD are at increased risk for pulmonary hypertension (PH). Cardiac catheterization is the gold standard for diagnosing PH, but cardiac catheterization is challenging to perform in small, sick, premature infants. The utility of echocardiography for diagnosing PH and predicting outcomes in extremely premature infants has not been clearly defined. Therefore, we sought to use predefined criteria to diagnose PH by echocardiogram and relate PH severity to mortality in extremely premature infants with BPD.

STUDY DESIGN

 Echocardiograms from 46 infants born ≤28 weeks' postmenstrual age with a diagnosis of BPD were assessed for PH by three pediatric cardiologists using predefined criteria, and survival times among categories of PH patients were compared. A total of 458 echocardiograms were reviewed, and 15 (33%) patients were found to have at least moderate PH. Patients with at least moderate PH had similar demographic characteristics to those with no/mild PH.

RESULTS

 Ninety percent of infants without moderate to severe PH survived to hospital discharge, compared with 67% of infants with at least moderate PH (p = 0.048). Patients with severe PH had decreased survival to hospital discharge (38%) compared with moderate (100%) and no/mild PH (90%) groups. Kaplan-Meier survival curves also differed among PH severity groups (Wilcoxon p < 0.001).

CONCLUSION

 Using predefined criteria for PH, premature infants with BPD can be stratified into PH severity categories. Patients diagnosed with severe PH by echocardiogram have significantly reduced survival.

KEY POINTS

· A composite score definition of PH by echocardiogram showed high inter- and intrarater reliability.. · Infants with severe PH by echocardiogram had decreased survival rates.. · Early diagnosis of PH by echocardiogram dictates treatment which may improve outcomes..

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.

Embracing the challenges of neonatal and paediatric pulmonary hypertension

Paediatric pulmonary arterial hypertension (PAH) shares common features with adult disease, but is associated with several additional disorders and challenges that require unique approaches. This article discusses recent advances, ongoing challenges and distinct approaches for caring for infants and children with PAH, as presented by the paediatric task force of the 7th World Symposium on Pulmonary Hypertension. We provide updates on diagnosing, classifying, risk-stratifying and treating paediatric pulmonary hypertension (PH) and identify critical knowledge gaps. An updated risk stratification tool and treatment algorithm is provided, now also including strategies for patients with associated cardiopulmonary conditions. Treatment of paediatric PH continues to be hindered by the lack of randomised controlled clinical trials. The challenging management of children failing targeted PAH therapy is discussed, including balloon atrial septostomy, lung transplantation and pulmonary-to-systemic shunt (Potts). A novel strategy using a multimodal approach for the management of PAH associated with congenital heart diseases with borderline pulmonary vascular resistance is included. Advances in diagnosing neonatal PH, especially signs and interpretation of PH by echocardiography, are highlighted. A team approach to the rapidly changing physiology of neonatal PH is emphasised. Challenges in drug approval are discussed, particularly the challenges of designing accurate paediatric clinical trials with age-appropriate end-points and adequate enrolment.

Optimizing management of chronic pulmonary hypertension in preterm infants: strategies for a complex population

PURPOSE OF REVIEW

Pulmonary hypertension (PH) is commonly observed in premature infants with bronchopulmonary dysplasia (BPD) and is associated with poor outcomes and increased mortality. This review explores the management of this intricate condition of the pulmonary vasculature, which exhibits heterogeneous effects and may involve both arterial and postcapillary components.

RECENT FINDINGS

Current management of BPD-PH should focus on optimizing ventilatory support, which involves treatment of underlying lung disease, transitioning to a chronic phase ventilation strategy and evaluation of the airway. Data on management is limited to observational studies. Diuretics are considered a part of the initial management, particularly in infants with right ventricular dilation. In many cases, pulmonary vasodilator therapy is required to induce pulmonary arterial vasodilation, reduce right ventricular strain, and prevent coronary ischemia and heart failure. Echocardiography plays a pivotal role in guiding treatment decisions and monitoring disease progression.

SUMMARY

BPD-PH confers a heightened risk of mortality and long-term cardio-respiratory adverse outcomes. Echocardiography has been advocated for screening, while catheterization allows for confirmation in select more complex cases. Successful management of BPD-PH requires a multidisciplinary approach, focusing on optimizing BPD treatment and addressing underlying pathologies.

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.

Biomarker screening for pulmonary hypertension in VLBW infants at risk for bronchopulmonary dysplasia

BACKGROUND

Very low birth weight (VLBW) infants demonstrate altered alveolar and pulmonary vascular development and carry an increased risk of developing bronchopulmonary dysplasia (BPD) and pulmonary hypertension (PH). Risk stratification for BPD-associated PH (BPD-PH) in at-risk infants may help tailor management, improve outcomes, and optimize resource utilization.

METHODS

VLBW infants were screened for PH with blood gas measurements, serum NT-proBNP and bicarbonate (HCO3) levels, and echocardiograms if they remained on respiratory support at 34 weeks corrected gestational age. We then tested 11 models using different cutoffs for NT-proBNP and HCO3 to predict infants at low risk of BPD-PH.

RESULTS

We identified PH in 34 of 192 (17.6%) VLBW infants. The median NT-proBNP in VLBWs with PH was 2769 pg/mL versus 917 pg/mL in those without PH (p < 0.0001). A model with NT-proBNP < 950 pg/mL and HCO3 < 32 mmol/L had a sensitivity of 100%, specificity of 34.2%, and negative predictive value of 100%. Using this model, 54 of 192 (28%) of the patients in this study would have been categorized as low risk for PH and could have avoided a screening echocardiogram.

CONCLUSION

NT-proBNP and HCO3 together may serve as sensitive and cost-effective screening tools for BPD-PH in VLBW infants.

IMPACT

NT-proBNP and HCO3 concentrations obtained together may help identify very low birth weight infants at risk for bronchopulmonary dysplasia who should undergo screening for pulmonary hypertension with echocardiography. This large dataset demonstrates that NT-proBNP and HCO3 levels together are more sensitive than NT-proBNP alone in identifying VLBW infants to undergo echocardiography. The combination of NT-proBNP and HCO3 levels may identify VLBW infants at low risk for pulmonary hypertension and thus those who may be able to avoid screening echocardiography.

Magnetic Resonance Imaging Assessment of Pulmonary Vascularity in Preterm Infants with Bronchopulmonary Dysplasia

INTRODUCTION

Pulmonary hypertension often complicates bronchopulmonary dysplasia (BPD) and infants with BPD plus pulmonary hypertension experience higher mortality rates. Current methods to evaluate pulmonary hypertension fail to evaluate the primary cause of this disease. We hypothesize that preterm infants with BPD experience altered pulmonary vascular growth and that magnetic resonance imaging (MRI) can be used to assess vascularity in BPD.

METHODS

In this observational cohort study, preterm infants with BPD (n = 33) and controls (n = 6) received a postnatal chest MRI that included a 2-dimensional time-of-flight acquisition. Semi-automatic segmentation was performed to measure vascularity parameters including vascular volume and density (vascular density = vascular volume/lung volume).

RESULTS

Vascular volume on MRI increases with post-menstrual age (877.2 mm3/week); however, the vascular density does not significantly change. Vascular volume is higher in infants with more severe BPD (p < 0.002), but vascular density did not significantly change when comparing mild, moderate, and severe BPD. Vascular density in infants with severe BPD requiring tracheostomy trended lower when compared to infants not requiring tracheostomy (0.18 mm3/mm3 vs. 0.27 mm3/mm3, p = 0.06). Vascular density increases with increasing days of inhaled nitric oxide (iNO) therapy in infants with severe BPD (0.02 mm3/mm3/week of iNO, rho = +0.56, p = 0.03).

CONCLUSION

Neonatal MRI can be used to assess pulmonary vascularity in preterm infants with BPD. Infants with BPD experience altered vascular growth and while higher vascular volume is associated with more severe BPD, lower vascular density trends toward worse clinical outcomes. Vascular density increases with iNO therapy in severe BPD.

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.

Strategies for the prevention of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a common morbidity affecting preterm infants and is associated with substantial long-term disabilities. The pathogenesis of BPD is multifactorial, and the clinical phenotype is variable. Extensive research has improved the current understanding of the factors contributing to BPD pathogenesis. However, effectively preventing and managing BPD remains a challenge. This review aims to provide an overview of the current evidence regarding the prevention of BPD in preterm infants, offering practical insights for clinicians.

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.

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.

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..

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.

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.

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.

Association of the respiratory severity score with bronchopulmonary dysplasia-associated pulmonary hypertension in infants born extremely preterm

OBJECTIVE

To test the hypothesis that elevations in the respiratory severity score (RSS) are associated with increased probability of bronchopulmonary dysplasia-associated pulmonary hypertension (BPD-PH).

STUDY DESIGN

Retrospective cohort study of infants born extremely preterm admitted to a BPD center between 2010 and 2018. Echocardiograms obtained ≥ 36 weeks' post-menstrual age (PMA) were independently adjudicated by two blinded cardiologists to determine the presence/absence of BPD-PH. Multivariable logistic regression estimated the association between RSS and BPD-PH.

RESULT

BPD-PH was observed in 68/223 (36%) of subjects. The median RSS at time of echocardiography was 3.04 (Range 0-18.3). A one-point increase in the RSS was associated with BPD-PH, aOR 1.3 (95% CI 1.2-1.4), after adjustment for gestational age and PMA at time of echocardiography.

CONCLUSION

Elevations in the RSS were associated with a greater probability of BPD-PH. Prospective studies are needed to determine the validity and performance of RSS as a clinical susceptibility/risk biomarker for BPD-PH.

Evaluation of preterm infants having bronchopulmonary dysplasia with echocardiography and serum biomarkers

BACKGROUND AND OBJECTIVES

Pulmonary hypertension is frequent in infants with bronchopulmonary dysplasia. Echocardiography is easy to perform, non-invasive, and recommended by guidelines even though solely it is not enough. Catheterisation is gold standard but invasive, expensive, and not cost effective. Therefore, we aimed to assess to find out the role of biomarkers besides echocardiography in the diagnosis of pulmonary hypertension in preterm with bronchopulmonary dysplasia.

METHODS

This study is done during the time period January 2016-2017. The diagnosis of pulmonary hypertension was assessed by echocardiography at 36 weeks later repeated at 3rd and 6th months. We also repeated biomarkers at 3rd and 6th months. The infants born ≤ 28 weeks in Erciyes University hospital who were diagnosed bronchopulmonary dysplasia were included. Infants with genetic syndromes, structural lung, and CHDs were excluded. Patients without bronchopulmonary dysplasia but having pulmonary hypertension due to other reasons and patients having echocardiograms without adequate images were excluded.

RESULTS

At initial, 21/59 patients had bronchopulmonary dysplasia-pulmonary hypertension (Group 1), 21/59 had no bronchopulmonary dysplasia-pulmonary hypertension (Group 2), and 17/59 had bronchopulmonary dysplasia without pulmonary hypertension (Group 3). Systolic pulmonary artery pressure and pulmonary vascular resistance were found high in Group 1 (36 mmHg; p <0.001, 1.25 Woods Unit; p < 0.0017, respectively). Tricuspid annular plane systolic excursion values of Group 1 were low. Median serum kallistatin levels of Group 1 were lower than the other groups (230.5 (114.5-300.5) µg/ml; p < 0.005). During the study period, pulmonary hypertension of 14/21 bronchopulmonary dysplasia-pulmonary hypertension resolved, six patients in Group 3 developed pulmonary hypertension. However, there was no difference in the biomarkers of these six patients.

CONCLUSION

In the diagnosis and the follow-up of pulmonary hypertension in bronchopulmonary dysplasia patients, besides echocardiography kallistatin, gelsolin, NT-probrain natriuretic peptide, homocysteine, and cystatin-C levels can be used. Further studies were required with large sample sizes.

Surfactant and neonatal hemodynamics during the postnatal transition

Surfactant replacement therapy (SRT) has revolutionized the management of respiratory distress syndrome (RDS) in premature infants, leading to improved survival rates and decreased morbidity. SRT may, however, be associated with hemodynamic changes, which can have both positive and negative effects on the immature cardiovascular system, during the transitional adaptation from fetal to extrauterine environment. However, there is a relative paucity of evidence in this domain, with most of them derived from small heterogeneous observational studies providing conflicting results. In this review, we will discuss the hemodynamic changes that occur with surfactant administration during this vulnerable period, focusing on available evidence regarding changes in pulmonary and systemic blood flow, cerebral circulation and their clinical implications.

Patent Ductus Arteriosus and Bronchopulmonary Dysplasia-Associated Pulmonary Hypertension: A Bayesian Meta-Analysis

Importance

Bronchopulmonary dysplasia (BPD) is often associated with pulmonary vascular disease and secondary pulmonary hypertension (PH). The pathogenesis of BPD-associated PH (BPD-PH) is complex and involves prenatal and postnatal factors that disrupt pulmonary vascular development, and patent ductus arteriosus (PDA) is a factor potentially associated with risk of BPD-PH that has been identified in very recent studies.

Objective

To explore the association of PDA with BPD-PH using a bayesian model-averaged (BMA) meta-analysis of studies.

Data Sources

PubMed and Embase were searched up to April 2023. Key search terms included BPD and PH.

Study Selection

Studies examining infants with gestational age 32 weeks or less and reporting data on PDA and risk of BPD-PH.

Data Extraction and Synthesis

This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and the Meta-Analysis of Observational Studies in Epidemiology reporting guidelines. Two independent reviewers extracted data, with a third reviewer checking for accuracy and completeness. Data pooling and effect size calculations were performed by BMA.

Main Outcomes and Measures

The primary outcome was BPD-PH. BMA was used to calculate Bayes factors (BFs). The BF10 is the ratio of the probability of the data under the alternative hypothesis (H1, association of PDA with BPD-HP) over the probability of the data under the null hypothesis (H0).

Results

A total of 32 studies (8513 infants) were included. BMA showed that the evidence in favor of H1 was weak for any PDA (BF10 = 2.90; 10 studies), moderate for hemodynamically significant PDA (BF10 = 3.77; 3 studies), and extreme for surgically ligated or catheter-occluded PDA (BF10 = 294.9; 16 studies). In contrast, the evidence in favor of H0 was weak for medically treated PDA (BF10 = 0.55; 6 studies). In addition, BMA found strong evidence in favor of H1 when prolonged exposure to PDA was analyzed as a dichotomous variable (BF10 = 11.80; 6 studies) and extreme evidence (BF10 = 113.60; 3 studies) when PDA exposure time was analyzed as a continuous variable.

Conclusions and Relevance

In this bayesian meta-analysis, the data suggest that prolonged exposure to PDA might be associated with increased risk of pulmonary vascular disease in extremely preterm infants. This highlights the need to monitor for PH in high-risk preterm infants with prolonged exposure to PDA and to incorporate PH risk into clinical decisions regarding PDA management.

Bronchopulmonary dysplasia - associated pulmonary hypertension: An updated review

Bronchopulmonary dysplasia (BPD) is the leading cause of chronic lung disease in infants and the commonest complication of prematurity. Advances in respiratory and overall neonatal care have increased the survival of extremely low gestational age newborns, leading to the continued high incidence of BPD. Pulmonary hypertension (PH) represents the severe form of the pulmonary vascular disease associated with BPD, and affects almost one-third of infants with moderate to severe BPD. PH responds suboptimally to pulmonary vasodilators and increases morbidity and mortality in BPD infants. An up-to-date knowledge of the pathogenesis, pathophysiology, diagnosis, treatment, and outcomes of BPD-PH can be helpful to develop meaningful and novel strategies to improve the outcomes of infants with this disorder. Therefore, our multidisciplinary team has attempted to thoroughly review and summarize the latest advances in BPD-PH in preventing and managing this morbid lung disorder of preterm infants.

Current diagnosis and treatment practice for pulmonary hypertension in bronchopulmonary dysplasia-A survey study in Germany (PUsH BPD)

Pulmonary hypertension (PH) is the most severe complication in preterm infants with bronchopulmonary dysplasia (BPD) and associated with significant mortality. Diagnostic and treatment strategies, however, still lack standardization. By the use of a survey study (PH in BPD), we assessed clinical practice (diagnosis, treatment, follow-up) in preterm infants with early postnatal persistent pulmonary hypertension of the newborn (PPHN) as well as at risk for or with established BPD-associated PH between 06/2018 and 10/2020 in two-thirds of all German perinatal centers with >70 very low birthweight infants/year including their cardiology departments and outpatient units. Data were analyzed descriptively by measures of locations and distributional shares. In routine postnatal care, clinical presentation and echocardiography were reported as the main diagnostic modalities to screen for PPHN in preterm infants, whereas biomarkers brain natriuretic peptide/N-terminal pro b-type natriuretic peptide were infrequently used. For PPHN treatment, inhaled nitric oxide was used in varying frequency. The majority of participants agreed to prescribe diuretics and steroids (systemic/inhaled) for infants at risk for or with established BPD-associated PH and strongly agreed on recommending respiratory syncytial virus immunization and the use of home monitoring upon discharge. Reported oxygen saturation targets, however, varied in these patients in in- and outpatient care. The survey reveals shared practices in diagnostic and therapeutic strategies for preterms with PPHN and BPD-associated PH in Germany. Future studies are needed to agree on detailed echo parameters and biomarkers to diagnose and monitor disease next to a much-needed agreement on the use of pulmonary vasodilators, steroids, and diuretics as well as target oxygen saturation levels.

Cardiopulmonary physiological effects of diuretic therapy in preterm infants with chronic pulmonary hypertension

OBJECTIVE

Using targeted neonatal echocardiography (TNE) to examine cardiopulmonary physiological impact of diuretics in preterm infants with chronic pulmonary hypertension (cPH).

STUDY DESIGN

Retrospective study comparing TNE indices pre- and ≤2 weeks (post) of initiating diuretic therapy in infants born <32 weeks gestational age with cPH.

RESULTS

Twenty-seven neonates with mean gestational age, birthweight and interval between pre-post diuretic TNE of 27.0 ± 2.8 weeks, 859 ± 294 grams, and 7.8 ± 3.0 days respectively were studied. Diuretics was associated with improvement in pulmonary vascular resistance [pulmonary artery acceleration time (PAAT); 34.27(9.76) vs. 40.24(11.10)ms, p = 0.01), right ventricular (RV) ejection time:PAAT ratio [5.92(1.66) vs. 4.83(1.14), p < 0.01)], RV fractional area change [41.6(9.8) vs. 46.4(6.5%), p = 0.03)] and left ventricular myocardial performance index [0.55(0.09) vs. 0.41(0.23), p < 0.01)]. Post-treatment, frequency of bidirectional/right-to-left inter-atrial shunts decreased significantly (24% vs. 4%, p = 0.05).

CONCLUSION

Primary diuretic treatment in neonates with cPH may result in improvement in PVR, RV and LV function and compliance.

Pharmacotherapy of BPD: Current status & future perspectives

Bronchopulmonary dysplasia (BPD) is a disease exclusive to prematurity and has changed in its definition since Northway first described it in 1967. There have been countless clinical trials evaluating the efficacy of drugs in the treatment and prevention of BPD in human subjects, and an even larger number of animal studies. Despite these, only a handful of drugs are used at the bedside today, primarily due to the lack of consistent efficacy seen in clinical trials or due to reports of adverse effects. This review summarizes the list of the most commonly used drugs and emerging new therapies which target BPD and BPD-related pulmonary hypertension (BPD-PH), including those which have shown promise in human trials but are not yet used routinely.

Recent Advances in Pediatric Pulmonary Hypertension: Implications for Diagnosis and Treatment

PURPOSE

Pediatric pulmonary hypertension (PH) is a condition characterized by elevated pulmonary arterial pressure, which has the potential to be life-limiting. The etiology of pediatric PH varies. When compared with adult cohorts, the etiology is often multifactorial, with contributions from prenatal, genetic, and developmental factors. This review aims to provide an up-to-date overview of the causes and classification of pediatric PH, describe current therapeutics in pediatric PH, and discuss upcoming and necessary research in pediatric PH.

METHODS

PubMed was searched for articles relating to pediatric pulmonary hypertension, with a particular focus on articles published within the past 10 years. Literature was reviewed for pertinent areas related to this topic.

FINDINGS

The evaluation and approach to pediatric PH are unique when compared with that of adults, in large part because of the different, often multifactorial, causes of the disease in children. Collaborative registry studies have found that the most common disease causes include developmental lung disease and subsets of pulmonary arterial hypertension, which includes genetic variants and PH associated with congenital heart disease. Treatment with PH-targeted therapies in pediatrics is often guided by extrapolation of adult data, small clinical studies in pediatrics, and/or expert consensus opinion. We review diagnostic considerations and treatment in some of the more common pediatric subpopulations of patients with PH, including developmental lung diseases, congenital heart disease, and trisomy 21.

IMPLICATIONS

The care of pediatric patients with PH requires consideration of unique pediatric-specific factors. With significant variability in disease etiology, ongoing efforts are needed to optimize treatment strategies based on disease phenotype and guide evidence-based practices.

Information Based Similarity Analysis of Oxygen Saturation Recordings to Detect Pulmonary Hypertension in Preterm Infants

Pulmonary hypertension (PH) is a complex cardiovascular condition associated with multiple morbidities and mortality risk in preterm infants. PH often complicates the clinical course of infants who have bronchopulmonary dysplasia (BPD), a more common lung disease in these neonates, causing respiratory deterioration and an even higher risk of mortality. While risk factors and prevalence of PH are not yet well defined, early screening and management of PH in infants with BPD are recommended by consensus guidelines from the American Heart Association. In this study, we propose a screening method for PH by applying a signal analysis technique to oxygen saturation in infants. Oxygen saturation data from infant groups with BPD (41 with and 60 without PH), recorded prior to their clinical PH diagnosis were analyzed in this study. An information-based similarity approach was applied to quantify the regularity of SpO2 fluctuations represented as binary words between adjacent five-minute segments. Similarity indices (SI) were observed to be lower in subjects with PH compared to those with BPD alone (p<0.001). These measures were also assessed for performance in screening for PH. SI of 7-bit words, exhibited 80% detection accuracy, 76% sensitivity and specificity of 83%. This index also exhibited a cross-validated mean (SD) F1-score of 0.80 (0.08) ensuring that sensitivity and recall of the screening were balanced. Similarity analysis of oxygen saturation patterns is a novel technique that can be potentially developed into a signal based early PH detection method to support clinical decision and care in this vulnerable population.

Efficacy of Sildenafil in Infants with Bronchopulmonary Dysplasia-Associated Pulmonary Hypertension

Background: Pulmonary hypertension (PH) is a common comorbidity in infants with bronchopulmonary dysplasia (BPD). Sildenafil is a widely recognized therapy for PH, but its efficacy in infants with BPD is questionable. We propose to assess the efficacy of sildenafil in BPD-associated PH as evaluated based on transthoracic echocardiography (TTE) changes and clinical measures. Methods: Data were retrospectively and prospectively collected. Inclusion criteria were gestational age (GA) < 32 weeks, birth weight (BW) < 1500 g with severe BPD, diagnosis of PH via TTE on sildenafil treatment. PH was evaluated via TTE, which was performed monthly after 36 weeks post-menstrual age (PMA) as a standard of care, and re-reviewed by a single pediatric cardiologist, who was blind to the initial reading. Results: In total, 19 patients were enrolled in the study, having a median GA of 24 3/7 weeks (IQR 23 5/7-25 5/7) and a median BW of 598 g (IQR 572-735). Sildenafil treatment was started at a median PMA of 40.4 weeks. The median respiratory severity score (RSS) at 28 d was 6.5, RSS and FiO2 showed improvement about 12 weeks after starting sildenafil treatment. Conclusions: Improvement in PH was noted via TTE, and patients had improvement in their RSS and FiO2 after prolonged therapy. However, TTE improvements did not correlate with clinical improvements.

Echocardiographic Assessment of Pulmonary Arterial Hypertension Following Inhaled Nitric Oxide in Infants with Severe Bronchopulmonary Dysplasia

OBJECTIVES

Inhaled nitric oxide (iNO) is an effective pulmonary vasodilator. However, the efficacy of iNO in former premature infants with established bronchopulmonary dysplasia (BPD) has not been studied. This study aimed to determine the efficacy of iNO in reducing pulmonary artery pressure in infants with severe BPD as measured by echocardiography.

STUDY DESIGN

Prospective, observational study enrolling infants born at less than 32 weeks gestation and in whom (1) iNO therapy was initiated after admission to our institution, or (2) at the outside institution less than 48 h before transfer and received an echocardiogram prior to iNO initiation, and (3) had severe BPD. Data were collected at three time-points: (1) before iNO; (2) 12-48 h after initiation of iNO; and (3) 48-168 h after initiation of iNO. The primary outcome was the effect of iNO on pulmonary artery pressure measured by echocardiography in patients with severe BPD between 48 and 168 h after initiating iNO therapy.

RESULTS

Of 37 enrolled, 81% had echocardiographic evidence of pulmonary arterial hypertension (PAH) before iNO and 56% after 48 h of iNO (p = 0.04). FiO2 requirements were significantly different between time-points (1) and (3) (p = 0.05). There were no significant differences between Tricuspid Annular Plane Systolic Excursion (TAPSE) Z-Scores, time to peak velocity: right ventricular ejection time (TPV:RVET), and ventilator changes.

CONCLUSIONS

Although we found a statistically significant reduction of PAH between time-point (1) and (3), future trials are needed to further guide clinical care.

Pulmonary Vascular Phenotypes of Prematurity: The Path to Precision Medicine

Pulmonary hypertension (PH) is associated with significant morbidities and high mortality in preterm infants, yet mechanisms contributing to the pathogenesis of PH, the impact of early pulmonary vascular disease (PVD) on the risk for BPD, the role for PH-targeted drug therapies, and long-term pulmonary vascular sequelae remain poorly understood. PVD is not a homogeneous disease, rather, PVD in the setting of prematurity includes various phenotypes as based on underlying pathophysiology, the severity of associated PH, the timing of disease onset, its contribution to hemodynamic and respiratory status, late outcomes, and other features. As with term newborns, severe hypoxemia with acute respiratory failure (HRF) in preterm infants can be due to marked elevation of pulmonary artery pressure with extrapulmonary shunt, traditionally referred to as persistent pulmonary hypertension of the newborn (PPHN). Transient and less severe levels of PH can also be observed during the early transition after birth without evidence of severe HRF, representing physiologic PH or delayed pulmonary vascular transition in preterm infants. Importantly, echocardiographic evidence of early PH has been strongly associated with the subsequent development of bronchopulmonary dysplasia (BPD), late PH, and chronic respiratory disease during infancy and early childhood. Late PH beyond the first postnatal months in preterm in neonates with established BPD is further associated with poor outcomes, especially as related to BPD severity. In addition, echocardiographic signs of PVD can further persist throughout childhood and may lead to chronic PH of variable severity and cardiac maldevelopment in prematurely born young adults. This review discusses the importance of characterizing diverse pulmonary vascular phenotypes in preterm infants to better guide clinical care and research, and to enhance the development of more precise therapeutic strategies to optimize early and late outcomes of preterm infants.

Patent ductus arteriosus and the risk of bronchopulmonary dysplasia-associated pulmonary hypertension

BACKGROUND

The aim of the study was to determine whether prolonged exposure to a moderate/large patent ductus arteriosus left-to-right shunt (PDA) increases the risk of late (beyond 36 weeks) pulmonary hypertension (BPD-PH) and pulmonary vascular disease (BPD-PVD) during the neonatal hospitalization in preterm infants (<28 weeks' gestation) with bronchopulmonary dysplasia (BPD).

METHODS

All infants requiring respiratory support ≥36 weeks had systematic echocardiographic evaluations for BPD-PH at planned intervals. Infants were classified as having either flow-associated BPD-PH (BPD-flow-PH) or BPD-PVD.

RESULTS

256 infants survived ≥36 weeks: 105 had NO BPD (were off respiratory support by 36 weeks); 151 had BPD. 22/151 had BPD-PH (12/22 had BPD-flow-PH from a PDA that persisted beyond 36 weeks; 10/22 had BPD-PVD). Moderate/large PDA shunts that persisted beyond 36 weeks were significantly associated with an increased incidence of BPD-PH due to BPD-flow-PH. We found no association between the duration of PDA exposure and the incidence of BPD-PVD.

CONCLUSIONS

Moderate/large PDA shunts increase the risk of flow-associated BPD-PH when present beyond 36 weeks. Although term infants with PDA-congenital heart disease can develop pulmonary vascular remodeling and PVD after months of PDA exposure, we found no echocardiographic evidence in preterm infants that prolonged PDA exposure increases the incidence of BPD-PVD during the neonatal hospitalization.

IMPACT

In our study, preterm infants (<28 weeks' gestation) with bronchopulmonary dysplasia (BPD) had a 15% incidence of pulmonary hypertension (PH) beyond 36 weeks' postmenstrual age as a comorbidity. Moderate/large patent ductus arteriosus (PDA) shunts increased the risk of flow-associated PH when present beyond 36 weeks. Although months of prolonged PDA exposure can cause pulmonary vascular remodeling and pulmonary vascular disease (PVD) in term infants with PDA-congenital heart disease, we found no echocardiographic evidence for an association between the duration of PDA exposure and the incidence of late PVD during the neonatal hospitalization in preterm infants with BPD.

Outcomes of patent foramen ovale greater than 3 mm at birth in extremely low birthweight infants

BACKGROUND

Foramen ovale (FO) is an obligate fetal shunt that typically resolves after birth, although patency throughout life is not uncommon. The natural history of patent FO (PFO) is known in term infants, but less is known about its course in extremely preterm infants. We describe the echocardiographic changes in FO size from birth to discharge in extremely low birth weight (ELBW) infants in this retrospective study.

METHODS

Cohort was divided based on size of FO at birth. Size of FO at discharge was measured and evaluated relative to postnatal weight gain. Demographics and clinical outcomes were compared between the two groups.

RESULTS

Of the 54 ELBW infants, 50 were born with FO less than 3 mm in diameter (small), and 4 were born with FO greater than 3 mm (large). Of small defects, the majority (44/50, 88%) did not increase in size with weight gain, and minority (6/50, 12%) increased in size, and three of these 6 patients, FO grew to be slightly larger than 3 mm. In contrast, all large defects (4 of 4, 100%) nearly doubled in size with postnatal growth. These 4 ELBW infants with enlargement of FO had a flap valve evident on echocardiogram obtained prior to discharge, and subsequently closed on outpatient follow-up echocardiograms, although time to resolution was variable (6 months - 3 years). One infant had presumptive resolution because of the presence of flap valve.

CONCLUSION

No maternal or neonatal demographic characteristics were predictive of FO enlargement, although, demonstrable flap valve on discharge echocardiogram correlated with resolution of FO on outpatient follow-up echocardiogram. Therefore, based on our data, we recommend that ELBW infants born with large FO should have echocardiographic re-evaluation of the atrial septal opening prior to discharge, to specify the presence of a flap valve or lack thereof, which is an important detail that can help a neonatologist determine the need for outpatient cardiac follow-up.

Developing a Respiratory Quality Improvement Program to Prevent and Treat Bronchopulmonary Dysplasia in the Neonatal Intensive Care Unit

Improvements in respiratory care have resulted in improved outcomes for preterm infants over the past three decades. To target the multifactorial nature of neonatal lung diseases, neonatal intensive care units (NICUs) should consider developing comprehensive respiratory quality improvement programs that address all drivers of neonatal respiratory disease. This article presents a potential framework for developing a quality improvement program to prevent bronchopulmonary dysplasia in the NICU. Drawing on available research and quality improvement reports, the authors discuss key components, measures, drivers, and interventions that should be considered when building a respiratory quality improvement program devoted to preventing and treating bronchopulmonary dysplasia.

Association of the Respiratory Severity Score with Bronchopulmonary Dysplasia-Associated Pulmonary Hypertension in Infants Born Extremely Preterm

Objective

To test the hypothesis that elevations in the respiratory severity score (RSS) are associated with increased risk of bronchopulmonary dysplasia-associated pulmonary hypertension (BPD-PH).

Study Design

Retrospective cohort study of infants born extremely preterm admitted to a BPD center between 2010-2018. Echocardiograms obtained ≥36 weeks' post-menstrual age (PMA) were independently adjudicated by two blinded cardiologists to determine the presence/absence of BPD-PH. Multivariable logistic regression estimated the association between RSS with BPD-PH.

Result

BPD-PH was observed in 68/223 (36%) of subjects. The median RSS at time of echocardiography was 3.04 (Range 0-18.3). A one-point increase in RSS was associated with BPD-PH, aOR 1.3 (95% CI 1.2-1.4), after adjustment for gestational age and PMA at time of echocardiography.

Conclusion

Elevations in the RSS were associated with a greater risk of BPD-PH. Prospective studies are needed to determine the validity and performance of RSS as a clinical susceptibility/risk biomarker for BPD-PH.

Diseases associated with prematurity in correlation with N-terminal pro-brain natriuretic peptide levels during the early postnatal life

The aim of this observational study was to investigate the influence of different typical preterm diseases on NT-proBNP serum levels in the early postnatal period of life of a preterm infant. NT-proBNP levels of 118 preterm infants born ≤ 31 weeks GA were determined at the first week of life, after 4 ± 1 weeks of life, and at a corrected gestational age of 36 + 2 weeks. Relevant complications with a possible influence on NT-proBNP values in the first week of life such as early neonatal infection, hemodynamically significant PDA (hsPDA), early pulmonary hypertension (early PH), and intraventricular hemorrhage (IVH) were evaluated; at 4 ± 1 weeks of life, bronchopulmonary dysplasia (BPD), BPD-related pulmonary hypertension (BPD-associated PH), late infection, IVH, and intestinal complications were evaluated. At a corrected gestational age of 36 ± 2 weeks, we examined the effect of retinopathy of prematurity (ROP), BPD, BPD-associated PH, and late infection on NT-proBNP levels. In the first days of life, only the isolated occurrence of hsPDA resulted in significantly increased NT-proBNP levels. In multiple linear regression analysis, early infection remained independently associated with NT-proBNP levels. At 4 ± 1 weeks of age, the isolated presence of BPD and BPD-related PH resulted in increased levels, and the effect remained significant in the multiple regression analysis. At a corrected gestational age of 36 ± 2 weeks, infants with relevant complications at this final evaluation time tended to have lower NT-proBNP values than our exploratory reference values.    Conlusion: NT-proBNP in the first week of life seems to be mainly influenced by an hsPDA and infection or inflammation. BPD and BPD-related PH are the most important factors influencing NT-proBNP serum levels in the first month of life. When preterm infants reach a corrected GA of 36 ± 2 weeks, chronological age rather than complications of prematurity must be considered when interpreting NT-proBNP levels. What is Known: • Several complications associated with prematurity, such as hemodynamically significant PDA, pulmonary hypertension, bronchopulmonary dysplasia, and retinopathy of prematurity, have been shown to influence NT-proBNP levels in preterm infants in their early postnatal life. What is New: • Hemodynamically relevant PDA is a major factor in the increase of NT-proBNP levels in the first week of life. • Bronchopulmonary dysplasia and pulmonary hypertension associated with bronchopulmonary dysplasia are important factors in the increase in NT-proBNP levels in preterm infants at approximately 1 month of age.

A multidisciplinary approach to severe bronchopulmonary dysplasia is associated with resolution of pulmonary hypertension

Objective

To describe our multidisciplinary bronchopulmonary dysplasia (BPD) consult team's systematic approach to BPD associated pulmonary hypertension (PH), to report our center outcomes, and to evaluate clinical associations with outcomes.

Study design

Retrospective cohort of 60 patients with BPD-PH who were referred to the Seattle Children's Hospital BPD team from 2018 to 2020. Patients with critical congenital heart disease were excluded. Demographics, comorbidities, treatments, closure of hemodynamically relevant intracardiac shunts, and clinical outcomes including time to BPD-PH resolution were reviewed.

Results

Median gestational age of the 60 patients was 25 weeks (IQR: 24-26). 20% were small for gestational age (SGA), 65% were male, and 25% received a tracheostomy. With aggressive cardiopulmonary management including respiratory support optimization, patent ductus arteriosus (PDA) and atrial septal defect (ASD) closure (40% PDA, 5% ASD, 3% both), and limited use of pulmonary vasodilators (8%), all infants demonstrated resolution of PH during the follow-up period, including three (5%) who later died from non-BPD-PH morbidities. Neither SGA status nor the timing of PH diagnosis (<36 vs. ≥36 weeks PMA) impacted the time to BPD-PH resolution in our cohort [median 72 days (IQR 30.5-166.5)].

Conclusion

Our multidisciplinary, systematic approach to BPD-PH management was associated with complete resolution of PH with lower mortality despite less sildenafil use than reported in comparable cohorts. Unique features of our approach included aggressive PDA and ASD device closure and rare initiation of sildenafil only after lack of BPD-PH improvement with respiratory support optimization and diagnostic confirmation by cardiac catheterization.

Pharmacotherapy for Pulmonary Hypertension in Infants with Bronchopulmonary Dysplasia: Past, Present, and Future

Approximately 8-42% of premature infants with chronic lung disease of prematurity, bronchopulmonary dysplasia (BPD), develop pulmonary hypertension (PH). Infants with BPD-PH carry alarmingly high mortality rates of up to 47%. Effective PH-targeted pharmacotherapies are desperately needed for these infants. Although many PH-targeted pharmacotherapies are commonly used to treat BPD-PH, all current use is off-label. Moreover, all current recommendations for the use of any PH-targeted therapy in infants with BPD-PH are based on expert opinion and consensus statements. Randomized Control Trials (RCTs) are needed to determine the efficacy of PH-targeted treatments in premature infants with or at risk of BPD-PH. Prior to performing efficacy RCTs, studies need to be conducted to obtain pharmacokinetic, pharmacodynamic, and safety data for any pharmacotherapy used in this understudied and fragile patient population. This review will discuss current and needed treatment strategies, identify knowledge deficits, and delineate both challenges to be overcome and approaches to be taken to develop effective PH-targeted pharmacotherapies that will improve outcomes for premature infants with or at risk of developing BPD-PH.

Outpatient prescription of pulmonary vasodilator therapy to preterm children with bronchopulmonary dysplasia

AIM

The use of pulmonary vasodilator therapy in children born preterm is largely unknown. Our aim was to map prescription patterns in children with bronchopulmonary dysplasia in Sweden.

METHODS

This was a descriptive national registry-based study of children <7 years who had been prescribed a pulmonary vasodilator during 2007-2017, were born preterm and classified as having bronchopulmonary dysplasia. Information on prescriptions, patient characteristics and comorbidities were retrieved from the Swedish Prescribed Drug Register and linked to other national registers.

RESULTS

The study included 74 children, 54 (73%) born at 22-27 weeks' gestation and 20 (27%) at 28-36 weeks. Single therapy was most common, n = 64 (86.5%), and sildenafil was prescribed most frequently, n = 69 (93%). Bosentan, iloprost, macitentan and/or treprostinil were used mainly for combination therapies, n = 10 (13.5%). Patent ductus arteriosus or atrial septal defect were present in 29 (39%) and 25 (34%) children, respectively, and 20 (69%) versus 3 (12%) underwent closure. Cardiac catheterisation was performed in 19 (26%) patients. Median duration of therapy was 4.6 (1.9-6.8, 95% CI) months. Mortality was 9%.

CONCLUSION

Preterm children with bronchopulmonary dysplasia were prescribed pulmonary vasodilators, often without prior catheterisation. Sildenafil was most commonly used. Diagnostic tools, effects, and drug safety need further evaluation.