The Impact of Atrial Left-to-Right Shunt on Pulmonary Hypertension in Preterm Infants with Moderate or Severe Bronchopulmonary Dysplasia

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.

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.

Risk factors for isolated atrial septal defect secundum morbidity

Atrial septal defect secundum is a common type of congenital heart defect and even more common among children born premature. The aim of this study was to assess premature birth as a potential associated risk factors for cardiac morbidity in children with isolated ASD II. In this retrospective national registry-based case-control study all children born in Sweden between 2010 and 2015 with an isolated ASD II diagnosis were included. Association between premature birth and cardiac morbidity in children with isolated ASD II was assessed by different outcomes-models using conditional logistic regression and adjustments were made for confounding factors. Overall, 11% of children with an isolated ASD II received treatment for heart failure. Down syndrome was the only independent risk factors for associated with cardiac morbidity in children with ASD II (OR = 2.25 (95%CI 1.25-4.07). Preterm birth in children was not associated with an increased risk of ASD II cardiac morbidity.

Should we "eliminate" PDA shunt in preterm infants? A narrative review

The patent ductus arteriosus frequently poses a significant morbidity in preterm infants, subjecting their immature pulmonary vascular bed to substantial volume overload. This, in turn, results in concurrent hypoperfusion to post-ductal organs, and subsequently alters cerebral blood flow. In addition, treatment has not demonstrated definitive improvements in patient outcomes. Currently, the optimal approach remains a subject of considerable debate with ongoing research controversy regarding the best approach. This article provides a comprehensive review of existing literature.

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.

Atrial septal defect closure is associated with improved clinical status in patients ≤ 10 kg with bronchopulmonary dysplasia

Patients with bronchopulmonary dysplasia (BPD) have shown clinical improvement after secundum atrial septal defect (ASD) closure. We sought to determine if this post-ASD closure improvement is secondary to the expected course in BPD patients or related to the closure itself. A novel BPD-ASD score was created to assess patients' clinical status (higher score = worse disease) and applied to 10 BPD-ASD inpatients weighing ≤ 10 kg who underwent ASD closure. The score and its subcomponents were retrospectively calculated serially ranging from 8 weeks pre- to 8 weeks post-intervention, and pre- and post-intervention score slopes were created. These slopes were compared using mixed regression modeling with an interaction term. There was a significant difference in pre- versus post-intervention slope with the most score drop the first week post-intervention (-2.1 + /- 0.8, p = 0.014). The mean score also dropped through weeks 2 (slope -0.8 + /- 0.8, p = 0.013) and 4 (slope -1.0 + /- 0.5, p = 0.001) post-intervention. There was a significant difference in pre- and post-intervention slopes for diuretics (p = 0.018) and the combined score of respiratory support, FiO2 need, and respiratory symptoms (p = 0.018). This study demonstrated significant improvement in BPD-ASD score, diuretic need, and respiratory status after ASD closure in BPD-ASD patients ≤ 10 kg that was outside of the natural course of BPD. Our study was limited by its small, single-center, retrospective nature. Future studies should be performed in a larger multicenter population to both validate the scoring system and compare to non-intervention infants.

The biventricular contribution to chronic pulmonary hypertension of the extremely premature infant

OBJECTIVE

Evaluate factors associated with significant pulmonary hypertension [PH] (≥2/3 systemic) and its impact on ventricular function at 36 weeks postmenstrual age (PMA).

STUDY DESIGN

Retrospective cohort of infants born at <29 weeks who survived to their echocardiography screening for PH at 36 weeks PMA. Masked experts extracted conventional and speckle-tracking echocardiography [STE] data.

RESULTS

Of 387 infants, 222 were included and 24 (11%) categorized as significant PH. Significant PH was associated with a decrease in tricuspid annular plane systolic excursion (0.79 vs 0.87 cm, p = 0.03), right peak longitudinal strain [pLS] by STE (-19.6 vs -23.1%, p = 0.003) and left pLS (-25.0 vs -22.7%, p = 0.02). The association between biventricular altered function by STE and significant PH persisted after adjustment for potential confounders - LV-pLS (p = 0.007) and RV-pLS (p = 0.01).

CONCLUSION

Our findings are suggestive that premature newborns with significant PH at 36 weeks PMA have a biventricular cardiac involvement to their pathophysiology.

Targeted neonatal echocardiography and lung ultrasound in preterm infants with chronic lung disease with and without pulmonary hypertension, screened using a standardized algorithm

Introduction

Increased recognition of the development of chronic pulmonary hypertension (cPH) in preterm infants with chronic lung disease (CLD) has prompted enhanced monitoring for the identification of different phenotypes.

Methods

All newborns consulted for oxygen/respiratory support dependency (CLD assessment) from January 2018 to December 2021 were included. TnECHO and LUS screening for cPH-CLD were performed at 36 weeks postmenstrual age. Cases of cPH related to increased pulmonary blood flow (cPH-IPBF) were referred to Pediatric Cardiology. The objective of the study was to identify all cases of cPH (cPH-CLD/IPBF) in the CLD patients screened and to compare outcomes. Following a standardized algorithm, cPH-CLD patients were treated with diuretics; ultrasounds taken before and after treatment were analyzed.

Results

Seventy-two patients with CLD were screened. Twenty-two (30%) had cPH-CLD, and nine (12%) had cPH-IPBF. cPH infants underwent more days of mechanical ventilation, were more likely to have retinopathy of prematurity, and showed increased mortality. The LUS pattern observed in the 72 CLD patients consisted of a thickened pleural line and a B-line interstitial heterogeneous pattern; 29% of patients were found to have lung consolidations. After diuretic therapy, step-down in respiratory support occurred in 59% of neonates with cPH-CLD. A decrease in respiratory rate (RR), right ventricular output (RVO), markers of pulmonary vascular resistance (PVR), and B-line pattern was observed. In tissue Doppler imaging, biventricular diastolic function was found to be modified after diuretics.

Conclusions

CLD infants with cPH showed increased morbidity and mortality. In cPH-CLD patients, a decrease in RR and step-down in respiratory support was observed after diuretic treatment. Follow-up ultrasound showed a decrease in RVO, markers of PVR, and B-lines.

A prediction model of pulmonary hypertension in preterm infants with bronchopulmonary dysplasia

OBJECTIVE

Pulmonary hypertension (PH) is a severe cardiovascular complication of bronchopulmonary dysplasia (BPD) that contributes to the high mortality rates for preterm infants. The objective of this study is to establish a prediction model of BPD-associated PH (BPD-PH) by integrating multiple predictive factors for infants with BPD.

METHOD

A retrospective investigation of the perinatal clinical records and data of echocardiography in all the preterm infants with BPD was performed from January 2012 to December 2019. A prediction model of BPD-PH was established based on the univariate and multivariate logistic regression analysis of the clinical data and evaluated by using the area under the receiver operating characteristic (ROC) curve (AUC), combined with the Hosmer-Lemeshow (HL) test. Internal validation was performed with bootstrap resampling.

RESULT

A total of 268 infants with BPD were divided into the BPD-PH group and the no-PH group. Multivariate logistic regression analysis showed that the independent predictive factors of BPD-PH were moderate to severe BPD, small for gestational age, duration of hemodynamically significant patent ductus arteriosus ≥ 28 days, and early PH. A prediction model was established based on the β coefficients of the four predictors. The area under the ROC curve of the prediction model was 0.930. The Hosmer-Lemeshow test (p = 0.976) and the calibration curve showed good calibration.

CONCLUSION

The prediction model based on the four risk factors predicts the development of BPD-PH with high sensitivity and specificity and might help clinicians to make individualized interventions to minimize the disease risk.

The high-risk factors of different severities of bronchopulmonary dysplasia (BPD) based on the national institute of child health and human development (NICHD) diagnosis criteria in 2018

Objective

To investigate the clinical characteristics of preterm infants with different severities of bronchopulmonary dysplasia (BPD) and disclose the high-risk factors of exacerbating BPD.

Methods

Collection of clinical data of 91 preterm infants admitted to the NICU and diagnosed with BPD, categorized in groups according to the disease severity: 41 mild cases,, 24 moderate cases, and 26 severe cases. Comparison and analysis of perinatal risk factors, treatment, complications and prognosis of the infants with different severity degrees.

Results

The severe group had a higher proportion of infants with congenital heart disease (CHD) higher than the moderate group (P < 0.05), and a higher ratio of pneumonia and mechanical ventilation (MV) ≥ seven days than the mild group (P < 0.05). The severe group also presented higher reintubation incidence than both the mild and moderate groups (P < 0.05). The groups presented different (P < 0.05) incidence rates of hemodynamically significant patent ductus arteriosus (hsPDA) . Ridit analysis suggested that the premature infants (PIs) with hsPDA, multiple microbial pulmonary infections, or Klebsiella pneumoniae pneumonia had more severe illness.

Conclusion

CHD, hsPDA, MV ≥ seven days, reintubation, pneumonia, especially multiple microbial pulmonary infections, and Klebsiella pneumoniae pneumonia are correlated with the severity of BPD and can be used as BPD progression predictor.

Pulmonary hypertension is an important co-morbidity in developmental lung diseases of infancy: Bronchopulmonary dysplasia and congenital diaphragmatic hernia

Bronchopulmonary dysplasia (BPD) following preterm birth and congenital diaphragmatic hernia (CDH) are both forms of developmental lung disease that may result in persistent pulmonary and pulmonary vascular morbidity in childhood. The pulmonary vascular disease (PVD) which accompanies BPD and CDH is due to developmental abnormalities and ongoing perinatal insults. This may be accompanied by evidence of elevated right heart pressures and pulmonary vascular resistance, leading to diagnosis of pulmonary hypertension (PH). The development of PH in these conditions is associated with increased morbidity and mortality in the vulnerable BPD and CDH populations. We present a review of PVD pathogenesis and evaluation in BPD and CDH and discuss management of related sequelae of PH co-morbidity for affected infants.

Risk Factors and Outcomes of Pulmonary Hypertension in Infants With Bronchopulmonary Dysplasia: A Meta-Analysis

Background: Pulmonary hypertension is one of the most common co-morbidities in infants with bronchopulmonary dysplasia (BPD), but its risk factors are unclear. The onset of pulmonary hypertension in BPD has been associated with poor morbidity- and mortality-related outcomes in infants. Two review and meta-analysis studies have evaluated the risk factors and outcomes associated with pulmonary hypertension in infants with BPD. However, the limitations in those studies and the publication of recent cohort studies warrant our up-to-date study. We designed a systematic review and meta-analysis to evaluate the risk factors and outcomes of pulmonary hypertension in infants with BPD. Objective: To systematically evaluate the risk factors and outcomes associated with pulmonary hypertension in infants with BPD. Methods: We systematically searched the academic literature according to the PRISMA guidelines across five databases (Web of Science, EMBASE, CENTRAL, Scopus, and MEDLINE). We conducted random-effects meta-analyses to evaluate the pulmonary hypertension risk factors in infants with BPD. We also evaluated the overall morbidity- and mortality-related outcomes in infants with BPD and pulmonary hypertension. Results: We found 15 eligible studies (from the initial 963 of the search result) representing data from 2,156 infants with BPD (mean age, 25.8 ± 0.71 weeks). The overall methodological quality of the included studies was high. Our meta-analysis in infants with severe BPD revealed increased risks of pulmonary hypertension [Odds ratio (OR) 11.2], sepsis (OR, 2.05), pre-eclampsia (OR, 1.62), and oligohydramnios (OR, 1.38) of being small for gestational age (3.31). Moreover, a comparative analysis found medium-to-large effects of pulmonary hypertension on the total duration of hospital stay (Hedge's g, 0.50), the total duration of oxygen received (g, 0.93), the cognitive score (g, -1.5), and the overall mortality (g, 0.83) in infants with BPD. Conclusion: We identified several possible risk factors (i.e., severe BPD, sepsis, small for gestational age, pre-eclampsia) which promoted the onset of pulmonary hypertension in infants with BPD. Moreover, our review sheds light on the morbidity- and mortality-related outcomes associated with pulmonary hypertension in these infants. Our present findings are in line with the existing literature. The findings from this research will be useful in development of efficient risk-based screening system that determine the outcomes associated with pulmonary hypertension in infants with BPD.

Repair of isolated atrial septal defect in infants less than 12 months improves symptoms of chronic lung disease or shunt-related pulmonary hypertension

INTRODUCTION

Infants with isolated atrial septal defects are usually minimally symptomatic, and repair is typically performed after infancy. Early repair may be considered if there is high pulmonary blood flow and reduced respiratory reserve or early signs of pulmonary hypertension. Our aim was to review the characteristics and outcomes of a cohort of patients who underwent infant repair at our institute.

METHODS

The study included 56 infants (28 female, 19 trisomy 21) with isolated atrial septal defect (age: 8 months (1.5-12), weight: 6 kg (2.8-7.5), echo Qp/Qs: 1.9 ± 0.1) who underwent surgical closure (20 fenestrated). Three groups were identified: 1) chronic lung disease and pulmonary hypertension (group A: n = 28%); 2) acutely unwell infants with pulmonary hypertension but no chronic lung disease (group B: n = 20, 36%); and 3) infants with refractory congestive heart failure without either pulmonary hypertension or chronic lung disease (group C: n = 9, 16%).

RESULTS

Post-operatively, pulmonary hypertension infants (47/56) showed improvement in tricuspid annular plane systolic excursion z-score (p < 0.001) and right ventricular systolic/diastolic duration ratio (p < 0.05). All ventilator (14.3%) or oxygen-dependent (31.6%) infants could be weaned within 2 weeks after repair. One year later, weight z-score increased in all patients and by +1 in group A, +1.3 in group B and +2 in group C. Over a median follow-up of 1.4 years, three patients died, four patients continued to have pulmonary hypertension evidence and two remained on targeted pulmonary hypertension therapy.

CONCLUSION

Atrial septal defect repair within the first year may improve the clinical status and growth in infants with early signs of pulmonary hypertension or those requiring respiratory support and facilitate respiratory management.

Pulmonary Hypertension Associated with Bronchopulmonary Dysplasia: A Review

Early pulmonary vascular disease (PVD) and established pulmonary hypertension (PH) are common associations of bronchopulmonary dysplasia (BPD). Diagnosis of PH is often made by echocardiography because of technical and logistic difficulties with the neonatal population. Optimization of respiratory support is the focus of treatment, however, medical therapies are being used with increased frequency. The prognosis for PH associated with BPD (PH-BPD) is tied to the child's respiratory status. PH is associated with increased risk of death in this population, so active screening and treatment is recommended to minimize morbidity and mortality. In this review, we discuss the pathophysiology of PH in infants with BPD, evaluate the current understanding of screening, diagnosis, and follow-up evaluation; describe comorbid conditions; and provide a framework for targeted physiology-based management strategies.

Mortality in infants with bronchopulmonary dysplasia: Data from cardiac catheterization

RATIONALE

Pulmonary hypertension (PH) is relatively common in infants with severe bronchopulmonary dysplasia (BPD), however, hemodynamic data and factors associated with mortality in this patient group are sparsely described in the literature.

OBJECTIVES

To characterize the hemodynamics of former preterm infants with BPD and PH, as measured at cardiac catheterization, and to identify respiratory and cardiovascular predictors of mortality.

METHODS

Single-center, retrospective cohort study, including, 30 patients born at less than 32-week gestational age (GA), who had an oxygen requirement at 36 weeks postmenstrual age and underwent cardiac catheterization between July 2014 and December 2017.

RESULTS

Median GA at birth was 25 5/7 weeks (interquartile range [IQR], 24 4/7-26 6/7 weeks). Median birth weight was 620 g (IQR, 530-700 g). With a median of 23 months of follow up (IQR, 11-39 months), mortality as of July 2018 was 27% (8 of 30). The alveolar-arterial oxygen gradient as a measure of lung disease did not correlate with mortality (log-rank test P = 0.28). However, indexed pulmonary vascular resistance (PVR) of greater than 3 Woods units × m ² showed a trend toward increased mortality (log-rank test P =  0.12). Pulmonary vein stenosis was the only predictor significantly associated with mortality (log-rank test P =  0.005).

CONCLUSIONS

In this cohort, the severity of lung disease as assessed by impaired oxygenation at cardiac catheterization did not correlate with mortality. The only factor significantly associated with mortality was the presence of pulmonary vein stenosis on cardiac catheterization, although PVR may also be an important factor.

Current understanding and perioperative management of pediatric pulmonary hypertension

Pediatric pulmonary hypertension is a complex disease with multiple, diverse etiologies affecting the premature neonate to the young adult. Pediatric pulmonary arterial hypertension, whether idiopathic or associated with congenital heart disease, is the most commonly discussed form of pediatric pulmonary hypertension, as it is progressive and lethal. However, neonatal forms of pulmonary hypertension are vastly more frequent, and while most cases are transient, the risk of morbidity and mortality in this group deserves recognition. Pulmonary hypertension due to left heart disease is another subset increasingly recognized as an important cause of pediatric pulmonary hypertension. One aspect of pediatric pulmonary hypertension is very clear: anesthetizing the child with pulmonary hypertension is associated with a significantly heightened risk of morbidity and mortality. It is therefore imperative that anesthesiologists who care for children with pulmonary hypertension have a firm understanding of the pathophysiology of the various forms of pediatric pulmonary hypertension, the impact of anesthesia and sedation in the setting of pulmonary hypertension, and anesthesiologists' role as perioperative experts from preoperative planning to postoperative disposition. This review summarizes the current understanding of pediatric pulmonary hypertension physiology, preoperative risk stratification, anesthetic risk, and intraoperative considerations relevant to the underlying pathophysiology of various forms of pediatric pulmonary hypertension.

Incidence, risk factors, and outcomes of pulmonary hypertension in preterm infants with bronchopulmonary dysplasia

Objectives

To determine the incidence and risk factors for pulmonary hypertension (PH) in preterm infants with moderate to severe bronchopulmonary dysplasia (BPD) and to compare short-term outcomes.

Methods

Preterm infants <32 weeks gestation born August 2013 through July 2015 with moderate to severe BPD at 36 weeks postmenstrual age were categorized into BPD-PH (exposure) and BPD-noPH (control) groups.

Results

Of 92 infants with BPD, 87 had echocardiographic assessment, of whom 24 (28%) had PH. On multiple logistic regression after adjustment for gestational age and sex, no significant risk factors for PH were identified based on data from this cohort. There were no differences in resource utilization or clinical outcomes including survival to discharge.

Conclusion

Approximately one out of four patients with moderate to severe BPD were identified as having PH. No significant risk factors for PH were identified. No differences in outcomes were identified for those with and without PH.

Association of Atrial Septal Defects and Bronchopulmonary Dysplasia in Premature Infants

OBJECTIVE

To evaluate the association between the presence of an atrial septal defect (ASD) and the odds of developing bronchopulmonary dysplasia (BPD) in premature infants.

STUDY DESIGN

We identified a cohort of infants that underwent at least one echocardiogram assessment, birth weight 501-1249 g, and gestational age 23-30 weeks discharged from the neonatal intensive care unit from 2004 to 2016. We used a BPD risk estimator to calculate the predicted risk of developing BPD at 6 postnatal ages within the first 28 days of life. We examined the association between the presence of an ASD and the development of BPD using 2 multivariable logistic regression models for each BPD risk severity on each postnatal day. The first model adjusted for predicted BPD risk and the second added therapeutic interventions for BPD.

RESULTS

Of 20 496 infants from 228 NICUs who met inclusion criteria, 8892 (43%) were diagnosed with BPD and 1314 (6%) had an ASD. BPD was present in 48% of infants with an ASD and 43% of infants without an ASD. In infants with an ASD, the OR of developing BPD was higher after adjusting for predicted risk of BPD plus therapeutic interventions, regardless of postnatal age or predicted BPD risk severity.

CONCLUSIONS

The presence of an ASD was associated with an increased odds of BPD in this cohort. Future trials should consider ASD as a potentially modifiable risk factor in this vulnerable population.

Identification of gaps in the current knowledge on pulmonary hypertension in extremely preterm infants: A systematic review and meta-analysis

BACKGROUND

Pulmonary hypertension complicates the clinical course of extremely preterm infants and is associated with bronchopulmonary dysplasia (BPD). However, prevalence, risk factors, and outcome of pulmonary hypertension in these infants are insufficiently known. This systematic review and meta-analysis aims to provide an up-to-date overview of available data on prevalence, risk factors, and outcome of pulmonary hypertension and to identify current knowledge gaps.

METHODS

Medline, EMBASE, and the Cochrane Library databases were searched in July 2017. Two authors reviewed titles/abstracts and full-texts. Eligible studies reported prevalence, patient characteristics or mortality of infants with/without pulmonary hypertension. Studies were excluded if they did not include extremely preterm infants. Only similar study samples (selected infants with BPD or infants both with/without BPD) were compared in the meta-analyses.

RESULTS

Of 1829 unique articles identified, 25 were eligible for inclusion. Pulmonary hypertension was observed in infants with BPD (20%, 95% confidence interval [CI] 14, 25), but also in those without BPD (2%, 95% CI 0, 8). Infants with severe BPD were most at risk of pulmonary hypertension (risk ratio [RR] 2.7, 95% CI 1.7, 4.2). Infants with pulmonary hypertension were more at risk of mortality (RR 4.7, 95% CI 2.7, 8.3).

CONCLUSIONS

Pulmonary hypertension occurs in particularly in infants with severe BPD, and increases risk of mortality. Due to selected study populations, heterogeneous pulmonary hypertension-definitions and poorly reported timing of pulmonary hypertension assessments, however, data available in current reports are insufficient to allow accurate assessment of true prevalence, risk factors, and time-related outcome. Prospective studies, with standardised methodology and follow-up are needed to determine these factors.

Atrial Septal Defects Accelerate Pulmonary Hypertension Diagnoses in Premature Infants

Between 4 and 16% of extremely premature infants have late pulmonary hypertension (PH) (onset >30 days of life), and infants with PH have a higher risk of tracheostomy and death. Atrial septal defects (ASD) increase pulmonary blood flow and may promote PH in at-risk infants. The objective of this study was to determine if infants with ASD develop PH sooner than those without ASD. Infants who were born at < 32 weeks' gestation, with an echocardiogram on day of life > 30, and without congenital anomalies were included. Infants with and without ASD were evaluated for the time to PH diagnosis, defined as the day of the first echocardiogram that showed PH. A multivariable model with ASD and significant variables on PH and a Cox proportional hazard model evaluating time to PH was determined. Of the 334 infants with echocardiograms, 57 had an ASD and 26% of these developed PH vs. 12% without ASD (p = 0.006). Infants with PH had lower gestational age (25.2 vs. 26.2 weeks, p = 0.005), smaller birthweight (699 vs. 816 gm, p = 0.001), and more prematurity complications than infants without PH. More PH infants had maternal African-American race (63.9 vs. 36.1%), right ventricular dysfunction (23.9 vs. 3.2%, p < 0.001), right ventricular dilation (52.1 vs. 8.6%, p < 0.001), or right ventricular hypertrophy (51.2 vs. 10.1%, p < 0.001), than infants without PH. At 150 days of life, 78.1% (95% CI 64.6-86.9%) of infants with ASD survived without PH, compared with 90.9% (95% CI 86.7-93.8%) of infants without ASD, and the unadjusted hazard for development of PH for infants with ASD was 2.37 (95% CI 1.29-4.36). When significant clinical variables were controlled, infants with ASD had a 2.44-fold (95% CI 1.27-4.68) increase in PH, compared with infants without ASD. Most PH in infants with or without ASD was diagnosed by day of life 150, but infants with ASD had an over 2-fold increased hazard for PH during their neonatal hospitalization. Premature infants with ASD should be followed closely for PH development and further studies to investigate the optimal timing of closure are needed.

Early characteristics of infants with pulmonary hypertension in a referral neonatal intensive care unit

Background

Approximately 8–23% of premature infants develop pulmonary hypertension (PH), and this diagnosis confers a higher possibility of mortality. As a result, professional societies recommend PH screening in premature infants. However, the risk factors for and the outcomes of PH may differ depending on the timing of its diagnosis, and little evidence is available to determine at-risk infants in the referral neonatal population. The objective of this study was to define clinical and echocardiographic characteristics of infants with pulmonary hypertension during the neonatal hospital course and at or near-term.

Methods

Infants who had the following billing codes: < 32 weeks, birth weight < 1500 g, neonatal unit, and echocardiograph had records abstracted from a data warehouse at Children’s Healthcare of Atlanta. The outcome was defined as late PH on the final echocardiogram for all patients, and, separately, for patients with multiple studies. Descriptive statistics, univariable, and multivariable models were evaluated, and odds ratios and 95% confidence intervals are expressed below as (OR, CI).

Results

556 infants were included in the overall study, 59 had PH on their final echocardiogram (11%). In multivariable analyses, atrial septal defect (2.9, 1.4–6.1), and intrauterine growth restriction (2.7, 1.2–6.3) increased the odds of late PH, whereas caffeine therapy decreased PH (0.4, 0.2–0.8). When the analyses were restricted to 32 infants who had multiple echocardiograms during their hospitalization, the association between atrial septal defect (5.9, 2.0–16.5) and growth restriction (3.7, 1.3–10.7) and late PH was strengthened, but the effect of caffeine therapy was no longer significant. In this smaller subgroup, infants with late PH had their final echocardiogram at a median of 116 days of life, and 42–74% of them had right ventricular pathology.

Conclusions

Early clinical variables are associated with PH persistence in a referral neonatal population. Identification of early clinical factors may help guide the ascertainment of infant risk for late PH, and may aid in targeting sub-groups that are most likely to benefit from PH screening.

Bronchopulmonary dysplasia and pulmonary hypertension: a meta-analysis

OBJECTIVE

Pulmonary hypertension (PH) is a complication of bronchopulmonary dysplasia (BPD) but the true impact of PH in patients with BPD remains unclear. We sought to systematically review and meta-analyze incidence of PH in BPD and compare clinical outcomes of BPD patients with PH to those without PH in preterm infants.

STUDY DESIGN

Medline, Embase, PsychINFO and CINAHL were searched from January 2000 through December 2015. Cohort, case-control and randomized studies were included. Case-reports, case-series and letters to editors and studies with high risk of bias were excluded. Study design, inclusion/exclusion criteria, diagnostic criteria for BPD and PH and outcomes were extracted independently by two co-authors.

RESULTS

The pooled incidence of PH in patients with BPD (any severity) was 17% (95% confidence interval (CI) 12 to 21; 7 studies) and 24% (95% CI 17 to 30; 9 studies) in moderate-severe BPD. Patients with BPD have higher unadjusted odds of developing PH compared to those without BPD (odds ratio (OR) 3.00; 95% CI 1.18 to 7.66; 4 studies). Patients with BPD and PH were at higher odds of mortality (OR 5.29; 95% CI 2.07 to 13.56; 3 studies) compared with BPD without PH, but there was no significant difference in duration of initial hospitalization, duration of supplemental oxygen requirement or need for home oxygen. No studies included in this review reported on long-term pulmonary or neurodevelopmental outcomes.

CONCLUSIONS

PH occurs in one out of 4 to 5 preterm neonates with BPD. Patients with BPD and PH may have higher odds of mortality; however, there is urgent need for high quality studies that control for confounders and provide data on long-term outcomes.

Early Complications After Percutaneous Closure of Atrial Septal Defect in Infants with Procedural Weight Less than 15 kg

Atrial septal defect (ASD) is the most common congenital cardiac lesion accounting for 10-15% of all cardiac malformations. In the majority of cases, the secundum type of the ASD is closed percutaneously in the catheterization laboratory. Although transcatheter closure of ASD is considered safe and effective in pediatric patients, there are limited data regarding the efficacy and safety of device ASD closure in smaller infants. The aim of this study was to determine risk of complications within 72 h following device closure of ASD in children of body weight <15 kg compared to larger children. Overall 252 children who underwent transcatheter closure of ASD at Children's Heart Centre in Lund, Sweden, between 1998 and 2015 were included. Data regarding demographics, comorbidity and complications occurring during and after device procedure until discharge were retrieved from the hospital's databases. Echocardiographic data were obtained from the digital and videotape recordings. Nearly half of the study cohort (n = 112; 44%) had a procedural weight <15 (median 11.3) kg with a median procedural age of 2.02 years. Among this study group, 22 (9%) children had post-procedural in-hospital complications, of which 16 (7%) were considered as major and six (2%) considered as minor. No deaths occurred. There was no significant difference in of the occurrence of major or minor complications between the two groups (p = 0.32). Larger ASD was more often associated with minor complications, OR 1.37 (95% CI 0.99-1.89), which most often consisted of transient arrhythmias during or after the procedure. Percutaneous ASD device closure can be performed safely in low-weight infants with a risk of post-procedural in-hospital complications comparable to larger/older children. Nevertheless, careful considerations of the indications to device closure is needed, particularly in children with larger ASD, as recommended by the current international guidelines for ASD closure.

Pulmonary hypertension in the premature infant: a challenging comorbidity in a vulnerable population

PURPOSE OF REVIEW

This review is written from the perspective of the pediatric clinician involved in the care of premature infants at risk for pulmonary hypertension. The main objective is to better inform the clinician in the diagnosis and treatment of pulmonary hypertension in premature infants by reviewing the available relevant literature and focusing on the areas for which there is the greatest need for continued research.

RECENT FINDINGS

Continued knowledge regarding the epidemiology of pulmonary hypertension in the premature infant population has aided better diagnostic screening algorithms. Included in this knowledge, is the association of pulmonary hypertension in infants with bronchopulmonary dysplasia (BPD). However, it is also known that beyond BPD, low birth weight and other conditions that result in increased systemic inflammation are associated with pulmonary hypertension. This information has led to the recent recommendation that all infants with BPD should have an echocardiogram to evaluate for evidence of pulmonary hypertension prior to discharge from the neonatal ICU.

SUMMARY

Pulmonary hypertension can be a significant comorbidity for premature infants. This review aims to focus the clinician on the available literature to improve recognition of the condition to allow for more timely interventions.