Assessing the agreement of chronic lung disease of prematurity diagnosis between radiologists and clinical criteria

BACKGROUND

Chronic lung disease of prematurity (CLD) is the most prevalent complication of preterm birth and indicates an increased likelihood of long-term pulmonary complications. The accurate diagnosis of this condition is critical for long-term health management. Numerous definitions define CLD with different clinical parameters and radiology findings, making diagnosis of the disease ambiguous and potentially inaccurate.

METHODS

95 patients were identified for this study, as determined by the diagnosis or confirmation of CLD in the impression of the radiologist's report on chest x-ray. Pulmonary function and complications were recorded at multiple benchmark timeframes within each patient's first few months of life and used for determining eligibility under each definition.

RESULTS

Each clinical definition of CLD had a high sensitivity for patients identified to have CLD by radiologists, correctly fitting over 90% of patients. Most patients included required invasive mechanical ventilation or positive pressure ventilation at 36 weeks postmenstrual age, indicating patients with radiographically confirmed CLD tended to have more severe disease. Radiologists tended to diagnose CLD before 36 weeks postmenstrual age, a timepoint used by multiple standard clinical definitions, with cases called earlier fitting under a larger percentage of definitions than those called later.

CONCLUSIONS

Radiologists tend to diagnose CLD in young patients with severe respiratory compromise, and can accurately diagnose the condition before developmental milestones for clinical definitions are met.

Do preterm infants with Bronchopulmonary dysplasia have a unique postnatal weight gain pattern?

OBJECTIVES

To investigate the weight gain pattern of preterm infants with bronchopulmonary dysplasia (BPD) during the hospital stay using weekly weight assessment methods.

METHODS

This single-center, retrospective, cohort study was carried out in Zekai Tahir Burak Maternal Health Education and Research Hospital between 2014 and 2018. One hundred fifty-one preterm infants <32 weeks of gestation and <1500 g of birth weight with BPD were compared to 251 babies without BPD in terms of weekly weight gain, standard deviation score (SDS), and fall in weight SDS till discharge.

RESULTS

Mean body weight was significantly lower in babies with BPD in all weeks except postnatal week (PW) 8. The groups had similar daily weight gain between birth and discharge (p = .78). Infants with BPD had lower weight SDS on postnatal day (PD) 14 and 21, and discharge, however similar on PD 28. The fall in SDS between PW 4 and discharge was significantly higher in the BPD group. Infants with BPD had higher fall in weight SDS between birth and discharge (p = .022). Discharge weight SDS was associated with gestational age and weight SDS on PW 4 in the whole cohort.

CONCLUSION

Infants with BPD showed a unique and unsteady pattern of growth compromise during the NICU course, most explicitly in early postnatal life and between PD 28-discharge. Future studies should consider not only the early postnatal life but also the period after four weeks of life till discharge to design an optimal nutrition strategy and decent growth for preterm infants with BPD.

Computed tomographic parenchymal lung findings in premature infants with pulmonary vein stenosis

BACKGROUND

Developmental pulmonary vein pulmonary vein stenosis in the setting of prematurity is a rare and poorly understood condition. Diagnosis can be challenging in the setting of chronic lung disease of prematurity. High-resolution non-contrast chest computed tomography (CT) is the conventional method of evaluating neonates for potential structural changes contributing to severe lung dysfunction and pulmonary hypertension but may miss pulmonary venous stenosis due to the absence of contrast and potential overlap in findings between developmental pulmonary vein pulmonary vein stenosis and lung disease of prematurity.

OBJECTIVE

To describe the parenchymal changes of pediatric patients with both prematurity and pulmonary vein stenosis, correlate them with venous disease and to describe the phenotypes associated with this disease.

MATERIALS AND METHODS

A 5-year retrospective review of chest CT angiography (CTA) imaging in patients with catheterization-confirmed pulmonary vein stenosis was performed to identify pediatric patients (< 18 years) who had a history of prematurity (< 35 weeks gestation). Demographic and clinical data associated with each patient were collected, and the patients' CTAs were re-reviewed to evaluate pulmonary veins and parenchyma. Patients with post-operative pulmonary vein stenosis and those with congenital heart disease were excluded. Data was analyzed and correlated for descriptive purposes.

RESULTS

A total of 17 patients met the inclusion criteria (12 female, 5 male). All had pulmonary hypertension. There was no correlation between mild, moderate, and severe grades of bronchopulmonary dysplasia and the degree of pulmonary vein stenosis. There was a median of 2 (range 1-4) diseased pulmonary veins per patient. In total, 41% of the diseased pulmonary veins were atretic. The right upper and left upper lobe pulmonary veins were the most frequently diseased (n = 13/17, 35%, n = 10/17, 27%, respectively). Focal ground glass opacification, interlobular septal thickening, and hilar soft tissue enlargement were always associated with the atresia of an ipsilateral vein.

CONCLUSION

Recognition of the focal parenchymal changes that imply pulmonary vein stenosis, rather than chronic lung disease of prematurity changes, may improve the detection of a potentially treatable source of pulmonary hypertension, particularly where nonangiographic studies result in a limited direct venous assessment.

Phthalate exposure in the neonatal intensive care unit is associated with development of bronchopulmonary dysplasia

OBJECTIVE

Bronchopulmonary dysplasia (BPD) is a serious yet common morbidity of preterm birth. Although prior work suggests a possible role for phthalate exposure in the development of BPD, no study has rigorously evaluated this. Our objective was to determine whether hospital-based phthalate exposure is associated with the development of BPD and to identify developmental windows sensitive to exposure.

STUDY DESIGN

This is a prospective multicenter cohort study of 360 preterm infants born at 23-33 weeks gestation participating in the Developmental Impact of NICU Exposures (DINE) cohort. 939 urine specimens collected during the NICU stay were analyzed for biomarkers of phthalate exposure by liquid chromatography with tandem mass spectrometry. The modified Shennan definition was used to diagnose bronchopulmonary dysplasia. Reverse distributed-lag modeling identified developmental windows sensitive to specific phthalate exposure, controlling for relevant covariates including sex and respiratory support.

RESULTS

Thirty-five percent of participants were diagnosed with BPD. Exposure to specific phthalate mixtures at susceptible points in preterm infant development are associated with later diagnosis of BPD in models adjusted for use of respiratory support. The weighted influence of specific phthalate metabolites in the mixtures varied by sex. Metabolites of di(2-ethylhexyl) phthalate, a phthalate previously linked to neonatal respiratory support equipment, drove this association, particularly among female infants, at 26- to 30-weeks post-menstrual age.

CONCLUSIONS

This is the largest and only multi-site study of NICU-based phthalate exposure and clinical impact yet reported. In well-constructed models accounting for infant sex and respiratory support, we found a significant positive association between ultimate diagnosis of BPD and prior exposure to phthalate mixtures with DEHP predominance at 26- to 30-weeks PMA or 34-36-weeks PMA. This information is critically important as it identifies a previously unrecognized and modifiable contributing factor to BPD.

AZTEC-azithromycin therapy for prevention of chronic lung disease of prematurity: a statistical analysis plan for clinical outcomes

Background

The AZTEC trial is a multi-centre, randomised, placebo-controlled trial of azithromycin to improve survival without development of chronic lung disease of prematurity (CLD) in preterm infants. The statistical analysis plan for the clinical outcomes of the AZTEC trial is described.

Methods and design

A double-blind, randomised, placebo-controlled trial of a 10-day course of intravenous azithromycin (20 mg/kg for 3 days; 10 mg/kg for 7 days) administered to preterm infants born at < 30 weeks’ gestational age across UK tertiary neonatal units. Following parental consent, infants are randomly allocated to azithromycin or placebo, with allocated treatment starting within 72 h of birth. The primary outcome is survival without moderate/severe CLD at 36 weeks’ postmenstrual age (PMA). Serial respiratory fluid and stool samples are being collected up to 21 days of life. The target sample size is 796 infants, which is based on detecting a 12% absolute difference in survival without moderate/severe CLD at 36 weeks’ PMA (90% power, two-sided alpha of 0.05) and includes 10% loss to follow-up.

Results

Baseline demographic and clinical characteristics will be summarised by treatment arm and in total. Categorical data will be summarised by numbers and percentages. Continuous data will be summarised by mean, standard deviation, if data are normal, or median, interquartile range, if data are skewed. Tests of statistical significance will not be undertaken for baseline characteristics. The primary analysis, on the intention to treat (ITT) population, will be analysed using multilevel logistic regression, within a multiple imputation framework. Adjusted odds ratios, 95% confidence intervals, and p-values will be presented. For all other analyses, the analysis population will be based on the complete case population, which is a modified ITT population. All analyses will be adjusted for gestational age and treatment arm and account for any clustering by centre and/or multiple births as a random effect.

Conclusion

We describe the statistical analysis plan for the AZTEC trial, including the analysis principles, definitions of the key clinical outcomes, methods for primary analysis, pre-specified subgroup analysis, sensitivity analysis, and secondary analysis. The plan has been finalised prior to the completion of recruitment.

Trial registration

ISRCTN registry ISRCTN11650227. Registered on 31 July 2018.

Bronchopulmonary dysplasia from chest radiographs to magnetic resonance imaging and computed tomography: adding value

Bronchopulmonary dysplasia (BPD) is a common long-term complication of preterm birth. The chest radiograph appearance and survivability have evolved since the first description of BPD in 1967 because of improved ventilation and clinical strategies and the introduction of surfactant in the early 1990s. Contemporary imaging care is evolving with the recognition that comorbidities of tracheobronchomalacia and pulmonary hypertension have a great influence on outcomes and can be noninvasively evaluated with CT and MRI techniques, which provide a detailed evaluation of the lungs, trachea and to a lesser degree the heart. However, echocardiography remains the primary modality to evaluate and screen for pulmonary hypertension. This review is intended to highlight the important findings that chest radiograph, CT and MRI can contribute to precision diagnosis, phenotyping and prognosis resulting in optimal management and therapeutics.

Lung function trajectories in children with post-prematurity respiratory disease: identifying risk factors for abnormal growth

Background

Survivors of prematurity are at risk for abnormal childhood lung function. Few studies have addressed trajectories of lung function and risk factors for abnormal growth in childhood. This study aims to describe changes in lung function in a contemporary cohort of children born preterm followed longitudinally in pulmonary clinic for post-prematurity respiratory disease and to assess maternal and neonatal risk factors associated with decreased lung function trajectories.

Methods

Observational cohort of 164 children born preterm ≤ 32 weeks gestation followed in pulmonary clinic at Boston Children’s Hospital with pulmonary function testing. We collected demographics and neonatal history. We used multivariable linear regression to identify the impact of neonatal and maternal risk factors on lung function trajectories in childhood.

Results

We identified 264 studies from 82 subjects with acceptable longitudinal FEV₁ data and 138 studies from 47 subjects with acceptable longitudinal FVC and FEV₁/FVC data. FEV₁% predicted and FEV₁/FVC were reduced compared to childhood norms. Growth in FVC outpaced FEV₁, resulting in an FEV₁/FVC that declined over time. In multivariable analyses, longer duration of mechanical ventilation was associated with a lower rate of rise in FEV₁% predicted and greater decline in FEV₁/FVC, and postnatal steroid exposure in the NICU was associated with a lower rate of rise in FEV₁ and FVC % predicted. Maternal atopy and asthma were associated with a lower rate of rise in FEV₁% predicted.

Conclusions

Children with post-prematurity respiratory disease demonstrate worsening obstruction in lung function throughout childhood. Neonatal risk factors including exposure to mechanical ventilation and postnatal steroids, as well as maternal atopy and asthma, were associated with diminished rate of rise in lung function. These results may have implications for lung function trajectories into adulthood.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01720-0.

Impact of the 2014 American Academy of Pediatrics Policy on RSV Hospitalization in Preterm Infants in the United States

Despite being a leading cause of hospitalization due to lower respiratory tract infections, the treatment of respiratory syncytial virus (RSV) infection is primarily supportive. Palivizumab is the only licensed immunoprophylaxis (IP) available for preventing severe RSV infection in high-risk populations including ≤ 35 weeks' gestational age (wGA) infants and children with chronic lung disease of prematurity or congenital heart disease. The American Academy of Pediatrics (AAP) has published its IP recommendations since the approval of palivizumab. In 2014, the AAP stopped recommending RSV IP in 29-34 wGA infants without comorbidities and stated that RSV hospitalization (RSVH) risk in otherwise healthy ≥ 29 wGA infants and term infants was similar. Since then, experts in the field have debated the appropriateness of the 2014 policy change, and several real-world evidence studies at the national and regional levels in the US have examined the impact of the AAP policy on 29-34 wGA infants. Overall, these studies showed a significant decline in RSV IP use and a concurrent increase in RSVH risk among 29-34 wGA infants relative to term infants in the seasons after the 2014 policy change. A similar decrease in IP use and increase in RSVH risk was also observed among < 29 wGA infants relative to term infants after the 2014 policy change. This decrease could be an unintended consequence as < 29 wGA infants are an in-policy population recommended to receive RSV IP. According to the National Perinatal Association, strong evidence exists to support the use of RSV IP in all ≤ 32 wGA and 32-35 wGA infants with risk factors such as attending day care, having ≥ 1 school-aged siblings, twin or greater multiple gestation, younger age, and exposure to parental smoking. Until new preventive and treatment options become available, palivizumab can help prevent and mitigate RSV disease burden among high-risk preterm infants.

Hospital-Acquired Viral Respiratory Tract Infections in the Neonatal Unit: A Comparison with Other Inpatient Groups

BACKGROUND

Hospital-acquired viral respiratory tract infections (VRTIs) cause significant morbidity and mortality in neonatal patients. This includes escalation of respiratory support, increased length of hospital stay, and need for home oxygen, as well as higher healthcare costs. To date, no studies have compared population rates of VRTIs across age groups.

AIM

Quantify the rates of hospital-acquired VRTIs in our neonatal population compared with other inpatient age groups in Nottinghamshire, UK.

METHODS

We compared all hospital inpatient PCR-positive viral respiratory samples between 2007 and 2013 and calculated age-stratified rates based on population estimates.

RESULTS

From a population of 4,707,217, we identified a previously unrecognised burden of VRTI in neonatal patients, only second to the 0-1-year-old group. Although only accounting for 1.3% of the population, half of the infections were in infants <1 year old and neonatal intensive care unit (NICU) patients. Human rhinovirus was the most dominant virus across the inpatient group, particularly in neonatal patients. Despite a two- to three-fold increase in the rate of positive samples in all groups during the colder months (1.1/1,000 October-March vs. 0.4/1,000 April-September), rates in the NICU did not change throughout the year at 4.3/1,000. Pandemic H1N1 influenza rates were 20 times higher in neonatal patients and infants <1 year old.

CONCLUSION

Good epidemiological and interventional data are needed to help inform visiting and infection control policies to reduce transmission of hospital-acquired viral infections to this vulnerable population, particularly during pandemic seasons.

Persistent and progressive long-term lung disease in survivors of preterm birth

Preterm birth accounts for approximately 11% of births globally, with rates increasing across many countries. Concurrent advances in neonatal care have led to increased survival of infants of lower gestational age (GA). However, infants born <32 weeks of GA experience adverse respiratory outcomes, manifesting with increased respiratory symptoms, hospitalisation and health care utilisation into early childhood. The development of bronchopulmonary dysplasia (BPD) - the chronic lung disease of prematurity - further increases the risk of poor respiratory outcomes throughout childhood, into adolescence and adulthood. Indeed, survivors of preterm birth have shown increased respiratory symptoms, altered lung structure, persistent and even declining lung function throughout childhood. The mechanisms behind this persistent and sometimes progressive lung disease are unclear, and the implications place those born preterm at increased risk of respiratory morbidity into adulthood. This review aims to summarise what is known about the long-term pulmonary outcomes of contemporary preterm birth, examine the possible mechanisms of long-term respiratory morbidity in those born preterm and discuss addressing the unknowns and potentials for targeted treatments.

Update on Vitamin E and Its Potential Role in Preventing or Treating Bronchopulmonary Dysplasia

Vitamin E is obtained only through the diet and has a number of important biological activities, including functioning as an antioxidant. Evidence that free radicals may contribute to pathological processes such as bronchopulmonary dysplasia (BPD), a disease of prematurity associated with increased lung injury, inflammation and oxidative stress, led to trials of the antioxidant vitamin E (α-tocopherol) to prevent BPD with variable results. These trials were all conducted at supraphysiologic doses and 2 of these trials utilized a formulation containing a potentially harmful excipient. Since 1991, when the last of these trials was conducted, both neonatal management strategies for minimizing oxygen and ventilator-related lung injury and our understanding of vitamin E isoforms in respiratory health have advanced substantially. It is now known that there are differences between the effects of vitamin E isoforms α-tocopherol and γ-tocopherol on the development of respiratory morbidity and inflammation. What is not known is whether improvements in physiologic concentrations of individual or combinations of vitamin E isoforms during pregnancy or following preterm birth might prevent or reduce BPD development. The answers to these questions require adequately powered studies targeting pregnant women at risk of preterm birth or their premature infants immediately following birth, especially in certain subgroups that are at increased risk of vitamin E deficiency (e.g., smokers). The objective of this review is to compile, update, and interpret what is known about vitamin E isoforms and BPD since these first studies were conducted, and suggest future research directions.

Bronchial hyper-responsiveness after preterm birth

Being born preterm often adversely affects later lung function. Airway obstruction and bronchial hyperresponsiveness (BHR) are common findings. Respiratory symptoms in asthma and in lung disease after preterm birth might appear similar, but clinical experience and studies indicate that symptoms secondary to preterm birth reflect a separate disease entity. BHR is a defining feature of asthma, but can also be found in other lung disorders and in subjects without respiratory symptoms. We review different methods to assess BHR, and findings reported from studies that have investigated BHR after preterm birth. The area appeared understudied with relatively few and heterogeneous articles identified, and lack of a pervasive understanding. BHR seemed related to low gestational age at delivery and a neonatal history of bronchopulmonary dysplasia. No studies reported associations between BHR after preterm birth and the markers of eosinophilic inflammatory airway responses typically found in asthma. This should be borne in mind when treating preterm born individuals with BHR and airway symptoms.

Recent Advances in Bronchopulmonary Dysplasia: Pathophysiology, Prevention, and Treatment

Bronchopulmonary dysplasia (BPD) is potentially one of the most devastating conditions in premature infants with longstanding consequences involving multiple organ systems including adverse effects on pulmonary function and neurodevelopmental outcome. Here we review recent studies in the field to summarize the progress made in understanding in the pathophysiology, prognosis, prevention, and treatment of BPD in the last decade. The work reviewed includes the progress in understanding its pathobiology, genomic studies, ventilatory strategies, outcomes, and therapeutic interventions. We expect that this review will help guide clinicians to treat premature infants at risk for BPD better and lead researchers to initiate further studies in the field.

Postnatal Infections and Immunology Affecting Chronic Lung Disease of Prematurity

Premature infants suffer significant respiratory morbidity during infancy with long-term negative consequences on health, quality of life, and health care costs. Enhanced susceptibility to a variety of infections and inflammation play a large role in early and prolonged lung disease following premature birth, although the mechanisms of susceptibility and immune dysregulation are active areas of research. This article reviews aspects of host-pathogen interactions and immune responses that are altered by preterm birth and that impact chronic respiratory morbidity in these children.

Randomized, Double-Blind Study of the Safety of the Liquid Versus Lyophilized Formulation of Palivizumab in Premature Infants and Children with Chronic Lung Disease of Prematurity

Introduction

To avoid the need for reconstitution required by lyophilized palivizumab, a liquid formulation was developed. This study assessed the safety and antidrug antibodies (ADA) of the liquid formulation of palivizumab compared with the lyophilized formulation.

Methods

This phase 4, randomized, double-blind, multicenter study included children with chronic lung disease of prematurity who were ≤24 months of age and children born prematurely with a gestational age of ≤35 weeks who were ≤6 months of age at randomization. Subjects were randomized 1:1 to 15 mg/kg of either liquid or lyophilized palivizumab administered via intramuscular injection every 30 days for a total of 5 injections. Safety was assessed based on serious adverse events (SAEs). ADA to palivizumab was assessed using blood collected at baseline and at a time point between study days 240 and 300.

Results

A total of 413 subjects were included in the analyses. The incidence of SAEs reported was 8.5% with liquid palivizumab and 5.9% with lyophilized palivizumab; none were deemed drug-related. The reported SAEs were consistent with expected conditions in this pediatric age group; there was no increase in respiratory syncytial virus (RSV) disease with liquid palivizumab. At study days 240–300, antipalivizumab antibodies were detected in none of the subjects in the liquid palivizumab group and in 1 subject in the lyophilized group. The true ADA percent positive, based on the upper limit of the 95% confidence interval (CI), was <1.5% for both treatments combined.

Conclusion

The frequency of detection of ADAs was low. The true ADA percent positive for both treatment groups combined based on the upper limit of the 95% CI was <1.5%. The type and frequency of SAEs reported were as expected, and there was no evidence of an increase in RSV disease with liquid palivizumab.

Electronic supplementary material

The online version of this article (doi:10.1007/s40121-014-0033-y) contains supplementary material, which is available to authorized users.

Long term cardiovascular consequences of chronic lung disease of prematurity

Pulmonary arterial (PA) hypertension in preterm infant is an important consequence of chronic lung disease of prematurity (CLD) arising mainly due to impaired alveolar development and dysregulated angiogenesis of the pulmonary circulation. Although PA pressure and resistance in these children normalise by school age, their pulmonary vasculature remains hyper-reactive to hypoxia until early childhood. Furthermore, there is evidence that systemic blood pressure in preterm born children with or without CLD is mildly increased at school age and in young adulthood when compared to term-born children. Arterial stiffness may be increased in CLD survivors due to increased smooth muscle tone of the pre-resistance and resistance vessels rather than the loss of elasticity in the large arteries. This review explores the long term effects of CLD on the pulmonary and systemic circulations along with their clinical correlates and therapeutic approaches.

Transcriptional responses of neonatal mouse lung to hyperoxia by Nrf2 status

Hyperoxia exposure can inhibit alveolar growth in the neonatal lung through induction of p21/p53 pathways and is a risk factor for the development of bronchopulmonary dysplasia (BPD) in preterm infants. We previously found that activation of nuclear factor erythroid 2 p45-related factor (Nrf2) improved survival in neonatal mice exposed to hyperoxia likely due to increased expression of anti-oxidant response genes. It is not known however, whether hyperoxic induced Nrf2 activation attenuates the growth impairment caused by hyperoxia in neonatal lung. To determine if Nrf2 activation modulates cell cycle regulatory pathway genes associated with growth arrest we examined the gene expression in the lungs of Nrf2(-/-) and Nrf2(+/+) neonatal mice at one and 3days of hyperoxia exposure.

METHODS

Microarray analysis was performed in neonatal Nrf2(+/+) and Nrf2(-/-) lungs exposed to one and 3days of hyperoxia. Sulforaphane, an inducer of Nrf2 was given to timed pregnant mice to determine if in utero exposure attenuated p21 and IL-6 gene expression in wildtype neonatal mice exposed to hyperoxia.

RESULTS

Cell cycle regulatory genes were induced in Nrf2(-/-) lung at 1day of hyperoxia. At 3days of hyperoxia, induction of cell cycle regulatory genes was similar in Nrf2(+/+) and Nrf2(-/-) lungs, despite higher inflammatory gene expression in Nrf2(-/-) lung.

CONCLUSION

p21/p53 pathways gene expression was not attenuated by Nrf2 activation in neonatal lung. In utero SUL did not attenuate p21 expression in wildtype neonatal lung exposed to hyperoxia. These findings suggest that although Nrf2 activation induces expression of anti-oxidant genes, it does not attenuate alveolar growth arrest caused by exposure to hyperoxia.