B-type natriuretic peptide and mortality in extremely low birth weight infants with pulmonary hypertension: a retrospective cohort analysis

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.

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.

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.

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.

Intermittent Hypoxemia and Bronchopulmonary Dysplasia with Pulmonary Hypertension in Preterm Infants

Rationale: Bedside biomarkers that allow early identification of infants with bronchopulmonary dysplasia-associated pulmonary hypertension (BPD-PH) are critically important, given the higher risk of death in these infants. Objectives: We hypothesized that infants with BPD-PH have patterns of intermittent hypoxemia (IH) that differ from infants with BPD without PH. Methods: We conducted a matched case-control study of extremely preterm infants from 22 weeks 0 days to 28 weeks 6 days born between 2018 and 2020 at the University of Alabama at Birmingham. BPD-PH status was determined using echocardiographic data performed after postnatal Day 28. Physiologic data were compared between infants with BPD-PH (cases) and BPD alone (control subjects). Receiver operating characteristic (ROC) analysis estimated the predictive ability of cumulative hypoxemia, desaturation frequency, and duration of intermittent hypoxemic events in the week preceding echocardiography to discriminate between cases and control subjects. Measurements and Main Results: Forty infants with BPD-PH were compared with 40 infants with BPD alone. Infants with and without PH had a similar frequency of IH events, but infants with PH had more prolonged hypoxemic events for desaturations below 80% (7 s vs. 6 s; P = 0.03) and 70% (105 s vs. 58 s; P = 0.008). Among infants with BPD-PH, infants who died had longer hypoxemic events below 70% (145 s vs. 72 s; P = 0.01). Using the duration of hypoxemic events below 70%, the areas under the ROC curves for diagnosis of BPD-PH and death in BPD-PH infants were 0.71 and 0.77, respectively. Conclusions: Longer duration of intermittent hypoxemic events was associated both with a diagnosis of BPD-PH and with death among infants with BPD-PH.

Successful treatment of pulmonary hypertension in a neonate with bronchopulmonary dysplasia: A case report and literature review

BACKGROUND

Pulmonary hypertension (PH) is a severe complication of bronchopulmonary dysplasia (BPD) in premature neonates and is closely related to prognosis. However, there is no effective and safe treatment for PH due to BPD in infants. Successful treatment for cases of BPD-associated PH with Tadalafil combined with bosentan is rare. This case may make a significant contribution to the literature because PH is difficult to manage as a serious complication of BPD in preterm infants. Mortality is high, especially when it is complicated by heart failure.

CASE SUMMARY

An extremely premature neonate with a gestational age of 26⁺⁵ wk and birth weight of 0.83 kg was diagnosed with BPD associated with PH; oral sildenafil did not improve the PH. The infant experienced sudden cardiac arrest and serious heart failure with severe PH. After a series of treatments, including cardiopulmonary resuscitation, mechanical ventilation, and inhaled nitric oxide (iNO), the respiratory and circulatory status improved but the pulmonary artery pressure remained high. Then oral sildenafil was replaced with oral tadalafil and bosentan; pulmonary artery pressure improved, and the infant recovered at our hospital. After 2 years of follow-up, she is in good condition, without any cardiovascular complications.

CONCLUSION

INO can effectively improve the respiratory and circulatory status of infants with PH associated with premature BPD. B-type natriuretic peptide should be routinely measured during hospitalization to evaluate the risk and prognosis of BPD-associated PH in preterm infants. Tadalafil combined with bosentan for the treatment of PH associated with premature BPD was better than sildenafil in this case. Further studies are needed to explore the efficacy and safety of different vasodilators in the treatment of PH associated with premature BPD.

B-type Natriuretic Peptide: A Diagnostic Biomarker for a Hemodynamically Significant PDA

Background: B-type natriuretic peptide (BNP) it has been reported to be a useful biomarker for the severity of hemodynamically significant patent ductus arteriosus (HsPDA) in premature infants. Objective: To assess serum levels of BNP in premature neonates with echocardiographically-confirmed hemodynamically significant and non-significant PDA (HnsPDA) and to explore the effect of PDA on left ventricular function. We also aimed to detect the level of BNP that differentiates between HsPDA and HnsPDA. Patients and methods: This was a cross-sectional observational study conducted on 73 randomly selected preterm neonates with HsPDA or hemodynamically nonsignificant PDA (HnsPDA), between May 2017 and May 2018. Echocardiography was done. BNP was measured using enzyme linked immunosorbent assay Results: There was no affection of left ventricular function in either group (LA/Ao ratio, FS, LVESD and LVEDD). PDA size, PFO size and PAP were significantly larger in HsPDA (p<0.001, p=0.001, p<0.001 respectively). Levels of BNP were significantly higher in HsPDA and correlated with the size of the PDA. At a cut-off value of 160.5 pg/ml, BNP had 80.49% sensitivity and 90.62% specificity with a positive predictive value of 91.7% and a negative predictive value of 78.04%, (AUC: 0.923, 95% C.I. 0.837 to 0.973). Conclusion: Levels of BNP in preterm babies with hemodynamically significant PDA rise early in neonatal life and correlate well with the size of the PDA. BNP can be used to screen for this condition. Ventricular dysfunction may not appear in the first 3 days of life.

Early diagnosis and targeted approaches to pulmonary vascular disease in bronchopulmonary dysplasia

Pulmonary hypertension has emerged as a life-threatening disease in preterm infants suffering from bronchopulmonary dysplasia (BPD). Its development is closely linked to respiratory disease, as vasculogenesis and alveologenesis are closely interconnected. Once clinically significant, BPD-associated pulmonary hypertension (BPD-PH) can be challenging to manage, due to poor reversibility and multiple comorbidities frequently associated. The pulmonary vascular disease process underlying BPD-PH is the result of multiple innate and acquired factors, and emerging evidence suggests that it progressively develops since birth and, in certain instances, may begin as early as fetal life. Therefore, early recognition and intervention are of great importance in order to improve long-term outcomes. Based on the most recent knowledge of BPD-PH pathophysiology, we review state-of-the-art screening and diagnostic imaging techniques currently available, their utility for clinicians, and their applicability and limitations in this specific population. We also discuss some biochemical markers studied in humans as a possible complement to imaging for the detection of pulmonary vascular disease at its early stages and the monitoring of its progression. In the second part, we review pharmacological agents currently available for BPD-PH treatment or under preclinical investigation, and discuss their applicability, as well as possible approaches for early-stage interventions in fetuses and neonates. IMPACT: BPD-associated PH is a complex disease involving genetic and epigenetic factors, as well as environmental exposures starting from fetal life. The value of combining multiple imaging and biochemical biomarkers is emerging, but requires larger, multicenter studies for validation and diffusion. Since "single-bullet" approaches have proven elusive so far, combined pharmacological regimen and cell-based therapies may represent important avenues for research leading to future cure and prevention.

Pulmonary hypertension in the child with bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is the most common chronic lung disease of prematurity resulting from complex interactions of perinatal factors that often lead to prolonged respiratory support and increased pulmonary morbidity. There is also growing appreciation for the dysmorphic pulmonary bed characterized by vascular growth arrest and remodeling, resulting in pulmonary vascular disease and its most severe form, pulmonary hypertension (PH) in children with BPD. In this review, we comprehensively discuss the pathophysiology of PH in children with BPD, evaluate the current recommendations for screening and diagnosis of PH, discern associated comorbid conditions, and outline the current treatment options.

N-terminal pro-B-type-natriuretic peptide as a screening tool for pulmonary hypertension in the paediatric population

BACKGROUND

Although cardiac catheterisation (cath) is the diagnostic test for pulmonary hypertension, it is an invasive procedure. Echocardiography (echo) is commonly used for the non-invasive diagnosis of pulmonary hypertension but maybe limited by lack of adequate signals. Therefore, emphasis has been placed on biomarkers as a potential diagnostic tool. No prior paediatric studies have simultaneously compared N-terminal pro-B-type-natriuretic peptide (NTproBNP) with cath/echo as a potential diagnostic tool. The aim of this study was to determine if NTproBNP was a reliable diagnostic tool for pulmonary hypertension in this population.

METHODS

Patients were divided into Study (echo evidence/established diagnosis of pulmonary hypertension undergoing cath) and Control (cath for small atrial septal defect/patent ductus arteriosus and endomyocardial biopsy post cardiac transplant) groups. NTproBNP, cath/echo data were obtained.

RESULTS

Thirty-one patients met inclusion criteria (10 Study, 21 Control). Median NTproBNP was significantly higher in the Study group. Echo parameters including transannular plane systolic excursion z scores, pulmonary artery acceleration time and right ventricular fractional area change were lower in the Study group and correlated negatively with NTproBNP. Receiver operation characteristic curve analysis demonstrated NTproBNP > 389 pg/ml was 87% specific for the diagnosis of pulmonary hypertension with the addition of pulmonary artery acceleration time improving the specificity.

CONCLUSIONS

NTproBNP may be a valuable adjunctive diagnostic tool for pulmonary hypertension in the paediatric population. Echo measures of transannular plane systolic excursion z score, pulmonary artery acceleration time and right ventricular fractional area change had negative correlations with NTproBNP. The utility of NTproBNP as a screening tool for pulmonary hypertension requires validation in a population with unknown pulmonary hypertension status.

Discriminant Analysis of Main Prognostic Factors Associated with Hemodynamically Significant PDA: Apgar Score, Silverman-Anderson Score, and NT-Pro-BNP Level

Hemodynamically significant patent ductus arteriosus (hsPDA) in premature newborns is associated with a risk of PDA-related morbidities. Classification into risk groups may have a clinical utility in cases of suspected hsPDA to decrease the need for echocardiograms and unnecessary treatment. This prospective observational study included 99 premature newborns with extremely low body weight, who had an echocardiogram performed within the first three days of life. Discriminant analysis was utilized to find the best combination of prognostic factors for evaluation of hsPDA. We used binary logistic regression analysis to predict the relationship between parameters and hsPDA. The cohort's mean and standard deviation gestational age was 27.6 ± 2.55 weeks, the mean birth weight was 1015 ± 274 g. Forty-six (46.4%) infants had a PDA with a mean diameter of 2.78 mm. Median NT-pro-BNP levels were 17,600 pg/mL for infants with a PDA and 2773 pg/mL in the non-hsPDA group. The combination of prognostic factors of hsPDA in newborns of extremely low body weight on the third day of life was determined: NT-pro-BNP, Apgar score, Silverman-Anderson score (Se = 82%, Sp = 88%). A cut-off value of NT-pro-BNP of more than 8500 pg/mL can predict hsPDA (Se = 84%, Sp = 86%).

B-natriuretic peptide serum levels in neonates with persistent pulmonary hypertension

Background

Better management of persistent pulmonary hypertension of neonates (PPHN) required new markers that can predict the response of patient to treatment and thus influence the medical decision to avoid short-term and long-term adverse effects. Hence, we aimed to evaluate B-natriuretic peptide (BNP) serum levels in neonates with PPHN and to correlate its levels with disease severity and response to treatment.

Patients and methods

The study included 60 neonates (30 PPHN patients and 30 healthy subjects). BNP was assessed, using the ELISA technique, at admission and after 4 days of treatment.

Results

Initial serum BNP levels were significantly higher in patients compared to controls (p < 0.001). Patients with mild severity showed lower BNP levels compared to patients with moderate severity, while patients with moderate severity showed decreased levels in comparison to severe cases (p < 0.001). The group of patients who showed remission after 4 days of treatment had lower pre-treatment and post-treatment BNP levels, compared to patients who showed incomplete remission. Initial levels of BNP showed strong positive correlations with pulmonary artery pressure (PAP) and oxygenation index (OI) before treatment (r = 0.9, p < 0.001 and r = 0.85, p = 0.001), while BNP after treatment showed moderate positive correlations with PAP before treatment (r = 0.6, p = 0.001) and OI before treatment (r = 0.6, p = 0.001). Analysis of the ROC curve revealed an AUC of 0.83with CI = 0.7–0.98 and p = 0.003.

Conclusions

BNP may play a role in the pathogenesis of PPHN, and BNP serum level can be used as a marker to detect disease severity and predict response to treatment.

Longitudinal B-Type Natriuretic Peptide Levels Predict Outcome in Infants with Congenital Diaphragmatic Hernia

OBJECTIVE

To evaluate B-type natriuretic peptide (BNP) as a longitudinal biomarker of clinical outcome in infants with congenital diaphragmatic hernia (CDH).

STUDY DESIGN

We conducted a retrospective study of 49 infants with CDH, classifying the cohort by respiratory status at 56 days, based on a proposed definition of bronchopulmonary dysplasia for infants ≥32 weeks' gestation: good outcome (alive with no respiratory support) and poor outcome (ongoing respiratory support or death). BNP levels were available at age 1-5 weeks. Longitudinal BNP trends were assessed using mixed-effects modeling. Receiver operating characteristic curves were generated to identify BNP cutoffs maximizing correct outcome classification at each time point. The time to reach BNP cutoff by outcome was assessed using Kaplan-Meier curves for weeks 3-5.

RESULTS

Twenty-nine infants (59%) had a poor outcome. Infants with a poor outcome were more likely than those with a good outcome to have liver herniated into the thorax (90% vs 50%; P = .002) and to undergo nonprimary repair (93% vs 35%; P < .001). Mixed-effects modeling demonstrated a differing decline in BNP over time by outcome group (P = .003 for interaction). BNP accurately predicted outcome at 3-5 weeks (area under the curve, 0.81-0.82). BNP cutoffs that maximized correct outcome classification decreased over time from 285 pg/mL at 3 weeks to 100 pg/mL at 4 weeks and 48 pg/mL at 5 weeks. Time to reach the cutoffs of 100 pg/mL and 48 pg/mL were longer in the poor outcome group (log-rank P = .006 and <.0001, respectively).

CONCLUSIONS

Elevated BNP accurately predicts poor outcome in infants with CDH at age 3-5 weeks, with declining cutoffs over 3-5 weeks of age.

Pulmonary hypertension in extremely preterm infants: a call to standardize echocardiographic screening and follow-up policy

Pulmonary hypertension (PH) is a frequent complication in extremely preterm born infants that seriously affects outcome. We aimed to describe the prevalence of PH in extremely preterm infants and the policy on screening and follow-up in the ten Dutch intensive care units (NICUs). We performed a retrospective cohort study at the University Medical Centre Groningen on infants with gestational age < 30 weeks and/or birthweight < 1000 g, born between 2012 and 2013. Additionally, we carried out a survey among the Dutch NICUs covering questions on the awareness of PH, the perceived prevalence, and policy regarding screening and following PH in extremely preterm infants. Prevalence of early-onset PH in our study was 26% and 5% for late-onset PH. PH was associated with poor survival and early-onset PH was associated with subsequent development of bronchopulmonary dysplasia (BPD). All the NICUs completed the questionnaire and we found that no standardized policy existed regarding screening and following PH in extremely preterm infants.Conclusion: Despite the frequent occurrence of PH and its clinically important consequences, (inter-)national standardized guidelines regarding screening and following of PH in extremely preterm infants are lacking. Standardizing screening and follow-up will enable early identification of infants with late-onset PH and allow for earlier treatment. Additionally, greater clarity is required regarding the prevalence of early PH as are new preventive treatment strategies to combat BPD. What is known? • Pulmonary hypertension (PH) substantially impairs the survival of extremely preterm infants. • PH is associated with bronchopulmonary dysplasia (BPD): Early-onset PH predicts the development of BPD. Late-onset PH is prevalent in infants with severe BPD. What is new? • Pulmonary hypertension (PH) is prevalent in preterm infants. Its consequences for morbidity and mortality justify a standardized policy aimed at early detection to improve prevention and treatment. • No structured policy exists in the Netherlands regarding screening/follow-up for PH in extremely preterm infants.

Updates on Management for Acute and Chronic Phenotypes of Neonatal Pulmonary Hypertension

Neonatal pulmonary hypertension is a heterogeneous disease in term and preterm neonates. It is characterized by persistent increase of pulmonary artery pressures after birth (acute) or an increase in pulmonary artery pressures after approximately 4 weeks of age (chronic); both phenotypes result in exposure of the right ventricle to sustained high afterload. In-depth clinical assessment plus echocardiographic measures evaluating pulmonary blood flow, pulmonary vascular resistance, pulmonary capillary wedge pressure, and myocardial contractility are needed to determine the cause and provide individualized targeted therapies. This article summarizes the causes, risk factors, hemodynamic assessment, and management of neonatal pulmonary hypertension.

Bronchopulmonary Dysplasia: Then, Now, and Next

Bronchopulmonary dysplasia (BPD) has evolved considerably since its first description over 50 years ago. This review aims to provide a historical framework for conceptualizing BPD and a current understanding of the changing definition, epidemiology, pathophysiology, treatment, and outcomes of BPD. The transdisciplinary approach that led to the initial phenotypic description of BPD continues to hold promise today. Investigators are refining the definition of BPD in light of changes in clinical care and increasing survival rates of very preterm infants. Despite improvements in perinatal care the incidence of BPD continues to increase. There is growing recognition that antenatal risk factors play a key role in the development of BPD. Strategies designed to prevent or limit neonatal lung injury continue to evolve. Defining the phenotype of infants with BPD can meaningfully direct treatment. Infants with BPD benefit from an interdisciplinary approach to longitudinal care with a focus on growth and neurocognitive development. While the ultimate impact of BPD on long-term pulmonary morbidity remains an active area of investigation, current data indicate that most children and adolescents with a history of BPD have a quality of life comparable to that of other preterm infants.

Urinary NT-proBNP as a potential noninvasive biomarker for screening of pulmonary hypertension in preterm infants: a pilot study

OBJECTIVE

This pilot study aimed to determine the feasibility of urinary NT-proBNP (NT-proBNP) as a potential noninvasive screening marker for pulmonary hypertension (PH).

STUDY DESIGN

A prospective cross-sectional study was conducted. Preterm infants (PI) (birthweight <1500 gm and <30 weeks gestational age (GA)) were enrolled. Serial urinary NT-proBNP measurements and echocardiograms (ECHO) were performed at 28, 32, and 36 weeks.

RESULTS

Thirty-six patients were included in the final analysis (BPD-PH group = 6, BPD group = 20, control = 10). Urinary NT-proBNP levels were higher in the BPD-PH group compared with BPD and control groups at all study intervals. A urine NT-proBNP cutoff level of 2345 pg/ml at 28 weeks of GA had a sensitivity and specificity of 83.3% and 84.2%, respectively, for detection of BPD-PH (AUC 0.816, p = 0.022).

CONCLUSION

Urinary NT-proBNP measurement is feasible in preterm infants and appears to be a good noninvasive screening tool for PH.

Natriuretic peptides in bronchopulmonary dysplasia: a systematic review

OBJECTIVES

To systematically review the diagnostic accuracy of brain natriuretic peptide (BNP) and amino-terminal pro-B-type natriuretic peptide (NT-proBNP) in bronchopulmonary dysplasia (BPD) and BPD-pulmonary hypertension (PH).

STUDY DESIGN

PubMed, Embase, the Web of Science, and the Cochrane Library were searched in March 2019. We included studies that evaluated BNP or NT-proBNP in preterm neonates as a marker for predicting BPD, BPD or death, and BPD-PH.

RESULTS

Nine studies evaluating NT-proBNP/BNP were included. The quality of evidence was low, using GRADE criteria. The diagnostic accuracy of NT-proBNP and BNP for diagnosing BPD-PH showed high sensitivity and specificity in infants with BPD. Lower sensitivities and specificities of NT-proBNP and BNP were reported for predicting BPD, BPD or death, compared with that for BPD-PH.

CONCLUSIONS

Low quality evidence suggests that NT-proBNP and BNP have adequate diagnostic accuracy for diagnosing and monitoring BPD-PH and may be used to triage patients to receive an echocardiogram.

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.

Oxygen Therapy and Pulmonary Hypertension in Preterm Infants

The goal of oxygen therapy and oxygen saturation targeting in extremely preterm infants is to improve outcomes and balance the risks associated with both hypoxemia and hyperoxemia. Although the NeOProM trials addressed whether low or high oxygen saturation targets affect the most important outcomes of extreme prematurity including death and other co-morbidities, the trials did not evaluate infants for pulmonary hypertension. There is limited evidence for the optimal oxygen saturation targets in extremely preterm infants that can be used to prevent the development of pulmonary hypertension and manage pulmonary hypertension once developed.

Predictive values of dyslipidemia and B-type natriuretic peptide levels in juvenile systemic lupus erythematosus: A two center-experience

B-type natriuretic peptide (BNP) is a biomarker that helps in determining the diagnosis and prognosis of heart failure (HF). There is an increased risk for cardiovascular disease (CVD) in systemic lupus erythematosus (SLE) with high disease activity, demonstrated by the higher frequency of dyslipidemia and higher BNP concentrations than in healthy controls. The aim of the work was to evaluate the association between the levels of lipids and BNP in pediatric patients with SLE with HF. We classified our subjects into three groups as follows: Group 1 (active SLE group): included 38 patients who subgrouped into 16 with HF and 22 without HF; Group 2 (inactive SLE group): included 38 patients, and Group 3 (control group): included 38 apparently healthy children. All children were subjected to complete history taking, clinical examination, SLE disease activity index scoring and investigations included complete blood count, erythrocyte sedimentation rate, 24-h urinary protein, anti-double strand deoxy-ribonucleic acid and anti-nuclear antibody, lipid profile, serum albumin, protein, and BNP. There was a significantly elevated lipid level and decreased high-density lipoproteins in lupus patients than in healthy controls. The dyslipidemia was more prevalent in active SLE. There were significantly elevated BNP levels in lupus patients than in healthy controls. In this study, we found that BNP was a biomarker in determining the diagnosis and prognosis of HF. This study revealed that BNP levels were increased in SLE patients without cardiac symptoms as compared to healthy controls; furthermore, the BNP levels were higher in active SLE patients with HF. The data indicated that there is a high risk for CVD in SLE with high disease activity, as demonstrated by the higher frequency of dyslipidemia and higher BNP concentrations than in healthy controls.

Screening Echocardiography and Brain Natriuretic Peptide Levels Predict Late Pulmonary Hypertension in Infants with Bronchopulmonary Dysplasia

Through this study, we aimed to assess the ability of routine neonatal screening at time of bronchopulmonary dysplasia (BPD) diagnosis to predict the development of late pulmonary hypertension (PHTN). This is a retrospective longitudinal cohort study of 37 premature infants with BPD assessing the utility of screening serum brain natriuretic peptide (BNP) and echocardiograms performed at the time of BPD diagnosis ('early PHTN') to predict 'late PHTN' at the last follow-up. Screening evaluation demonstrated early PHTN in 9/37 patients. At an average follow-up interval of 52.7 ± 38.7 weeks, 4/9 had late PHTN; one patient without early PHT had late PHT. At initial screening, infants with late PHTN were significantly more likely to have demonstrated elevated BNP values (p = 0.003), and echocardiographic evidence of right atrial dilatation (p = 0.01), right ventricular hypertrophy (p = 0.01), lower right ventricular area change percentage (p = 0.03), and larger main pulmonary artery Z-scores (p = 0.02). Serum BNP and echocardiographic evaluation performed at the time of BPD diagnosis can detect patients at increased risk of late PHTN. Large, prospective studies are necessary to further address this question.

Successful Management of Pulmonary Arterial Hypertension by Monitoring N-Terminal Pro-B-Type Natriuretic Peptide Serum Levels in a Preterm Infant with Chronic Lung Disease: A Case Report

We measured the serial changes in N-terminal probrain natriuretic peptide (NT-proBNP) levels in a 6-month-old male infant with chronic lung disease (CLD) complicated by pulmonary arterial hypertension (PAH). The patient was born at the 24th week of gestation weighing 695 g. At 1 month after birth, an echocardiogram confirmed the diagnosis of CLD with PAH. He was treated with inhaled nitric oxide (iNO) and oral sildenafil and discharged from the hospital. At 190 days of age, the patient was readmitted to our department because of a viral upper respiratory infection. At 195 days of age, his respiratory condition worsened with pulmonary edema and his NT-proBNP level was determined to be 10,117 pg/mL. The patient was immediately administered iNO, and his respiratory condition improved, and NT-proBNP levels decreased. However, he experienced repeated severe cyanosis attacks. Before the attacks, his NT-proBNP level was > 1,000 pg/mL. Therefore, we continuously administered iNO until his NT-proBNP level decreased to < 1,000 pg/mL. We safely discontinued iNO administration at 473 days of age. In conclusion, serial change in NT-proBNP is a surrogate marker with prognostic value in patients with PAH associated with CLD.

N-Terminal Pro-B-Type Natriuretic Peptide as a Biomarker of Bronchopulmonary Dysplasia or Death in Preterm Infants: A Retrospective Cohort Analysis

Objectives: To investigate the association between serum N-terminal pro-B-type natriuretic peptide (NT-proBNP) level on the first day of life and a composite outcome of bronchopulmonary dysplasia (BPD) or death in a cohort of infants born before 32 weeks of gestation. Methods: We retrospectively identified infants born before 32 weeks of gestation who had serum NT-proBNP levels measured when they were admitted to the Neonatal Intensive Care Unit shortly after birth. The outcome of BPD or death was assessed at 36 weeks of postmenstrual age. The association of serum NT-proBNP levels with BPD or death was evaluated. Receiver operator characteristic (ROC) curve analysis was used to evaluate the predictive performance of serum NT-proBNP levels. Results: A 100 and 47 preterm infants had serum NT-proBNP levels measured on the first day of life. Serum NT-proBNP level was significantly higher in preterm infants who developed moderate/severe BPD or died [3,855 (2,567-6,369) vs. 1,259 (950-2,035) in control infants, P < 0.001]. On binary regression analysis, a high natural logarithm of serum NT-proBNP levels was associated with increased risk of moderate/severe BPD or death adjusted for gestational age, birth weight, birth weight z-score, and Apgar scores at 1 and 5 min (odds ratio [OR] = 5.195, 95% confidence interval [CI] 2.667-10.117, P < 0.001). ROC analysis identified a NT-proBNP level of 2002.5 pg/mL to have 87.5% sensitivity and 74.7% specificity for predicting moderate/severe BPD or death. The area under the curve (AUC) was 0.853 (95% CI 0.792-0.914). Conclusion: Serum NT-proBNP level measured on the first day of life is a promising biomarker for predicting the development of moderate/severe BPD or death in preterm infants. Our findings warrant a larger prospective study to incorporate measurement of NT-proBNP in prognosticating outcomes in very preterm infants.

Using clinical and genetic data to predict pulmonary hypertension in bronchopulmonary dysplasia

AIM

Pulmonary hypertension significantly increases morbidity and mortality in infants with bronchopulmonary dysplasia. The frequency of single nucleotide polymorphisms in arginase-1 (ARG1 rs2781666) and dimethylarginine dimethylaminohydrolase-1 (DDAH1 rs480414) genes has been found to differ in a cohort of bronchopulmonary dysplasia patients with pulmonary hypertension (cases) and without pulmonary hypertension (controls). Therefore, we tested the hypothesis that combining these genotypes with phenotypic data would better predict pulmonary hypertension in bronchopulmonary dysplasia patients.

METHODS

Bronchopulmonary dysplasia patients (n = 79) born at <35 weeks gestation were studied. Pulmonary hypertension was diagnosed by echocardiographic criteria (n = 20). ROC curves to predict pulmonary hypertension in bronchopulmonary dysplasia were generated from genotype and/or clinical data.

RESULTS

Cases were born at an earlier gestation and weighed less at birth than did controls. ROC curves for rs2781666 had an AUC of 0.61, while rs480414 had an AUC of 0.66. Together, the AUC was 0.70. When clinical data were added to the genetic model, AUC was 0.73.

CONCLUSION

These findings demonstrate that ROC predictive modelling of pulmonary hypertension in bronchopulmonary dysplasia improves with inclusion of both genotypic and phenotypic data. Further refinement of these types of models could facilitate the implementation of precision medicine approaches to pulmonary hypertension in bronchopulmonary dysplasia.

An update on the diagnosis and management of bronchopulmonary dysplasia (BPD)-associated pulmonary hypertension

The past decade of neonatal care has been highlighted by increased survival rates in smaller and more premature infants. Despite reduction in mortality associated with extreme prematurity, long term pulmonary morbidities remain a concern, with growing recognition of the clinical burden attributable to infants with bronchopulmonary dysplasia (BPD)-associated pulmonary hypertension (PH). Recent publications shed light on the critical contributions of maternal placental pathology and compromised intrauterine growth to fetal pulmonary vascular development. A body of literature has further clarified postnatal risk factors for PH, most notably the severity of BPD but surprisingly the additional presence of non-pulmonary morbidities including necrotizing enterocolitis (NEC). Limitations of current diagnostics persist with growing consideration of novel echocardiographic approaches as well as complementary non-invasive biomarkers to better identify infants at risk. In 2015, a joint report published by the American Heart Association and American Thoracic Society provided the first guidelines for the care of children with PH with limited content to address BPD-associated PH. These guidelines were expanded upon in an expert consensus report produced by the Pediatric Pulmonary Hypertension Network (PPHNet). These recommendations encouraged the use of standardized screening protocols and emphasized the importance of evaluation and treatment of comorbidities when PH is identified. Cardiac catheterization was recommended prior to initiation of therapy for more accurate quantification of pulmonary pressures, clarification of anatomy and guidance in the use of pharmacotherapy. Despite these guidelines, significant practice variation persists and gaps remain with respect to optimal evaluation and management of BPD-associated PH.

Sildenafil Use in the Treatment of Bronchopulmonary Dysplasia-Associated Pulmonary Hypertension: A Case Series

Objective  This article studies the role of sildenafil in reducing myocardial stress (measured by serial N-terminal pro b-type natriuretic peptide [NTproBNP] levels) secondary to bronchopulmonary dysplasia-associated pulmonary hypertension (BPD-PH). Study Design  This is a case series of three extremely low birth weight infants with severe BPD at 36 weeks' postmenstrual age. All infants had very elevated NTproBNP (> 2,000 ng/dL) levels and echocardiographic evidence of BPD-PH. Sildenafil was started and infants were followed up every 2 weeks clinically along with NTproBNP levels and echocardiograms. Results  After 4 weeks of sildenafil treatment, NTproBNP levels decreased significantly in all infants, echocardiograms showed significant improvement in one infant, and respiratory severity score improved significantly in one infant. All infants tolerated sildenafil. Conclusion  Sildenafil reduced NTproBNP levels in all infants with BPD-PH but the echocardiographic findings and respiratory scores did not improve consistently. We speculate that this may be due to a delay in diagnosis and initiation of therapy after irreversible pulmonary changes have set in.

NTproBNP as a surrogate biomarker for early screening of pulmonary hypertension in preterm infants with bronchopulmonary dysplasia

OBJECTIVE

Pulmonary hypertension (PH) is a known complication of bronchopulmonary dysplasia (BPD). This study aimed to determine the utility of serial N-Terminal pro-Brain Natriuretic Peptide (NTproBNP) levels in the screening of BPD associated PH (BPD-PH) in preterm infants.

STUDY DESIGN

Infants with birth weight <1500 g and <30 week corrected gestational age (CGA) were followed with serial NTproBNP levels and echocardiograms (ECHO). They were divided into control, BPD and BPD-PH groups. Statistical analyses included repeated measures analysis of variance and receiver operator curve (ROC) generation.

RESULTS

Infants in the BPD-PH and BPD group had significantly elevated NTproBNP levels as compared to the control group. ROC curves for NTproBNP at 28 weeks CGA provided a cut-point of 2329 pg/ml and 578.1 pg/ml for detection of BPD-PH and BPD, respectively.

CONCLUSIONS

NTproBNP appears to be a good screening tool to determine the onset of BPD-PH as early as 28 weeks CGA.

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.

Pulmonary hypertension associated with bronchopulmonary dysplasia in preterm infants

Bronchopulmonary dysplasia (BPD) and BPD-associated pulmonary hypertension (BPD-PH) are chronic inflammatory cardiopulmonary diseases with devastating short- and long-term consequences for infants born prematurely. The immature lungs of preterm infants are ill-prepared to achieve sufficient gas exchange, thus usually necessitating immediate commencement of respiratory support and oxygen supplementation. These therapies are life-saving, but they exacerbate the tissue damage that is inevitably inflicted on a preterm lung forced to perform gas exchange. Together, air-breathing and necessary therapeutic interventions disrupt normal lung development by aggravating pulmonary inflammation and vascular remodelling, thus frequently precipitating BPD and PH via an incompletely understood pathogenic cascade. BPD and BPD-PH share common risk factors, such as low gestational age at birth, fetal growth restriction and perinatal maternal inflammation; however, these risk factors are not unique to BPD or BPD-PH. Occurring in 17-24% of BPD patients, BPD-PH substantially worsens the morbidity and mortality attributable to BPD alone, thus darkening their outlook; for example, BPD-PH entails a mortality of up to 50%. The absence of a safe and effective therapy for BPD and BPD-PH renders neonatal cardiopulmonary disease an area of urgent unmet medical need. Besides the need to develop new therapeutic strategies, a major challenge for clinicians is the lack of a reliable method for identifying babies at risk of developing BPD and BPD-PH. In addition to discussing current knowledge on pathophysiology, diagnosis and treatment of BPD-PH, we highlight emerging biomarkers that could enable clinicians to predict disease-risk and also optimise treatment of BPD-PH in our tiniest patients.

Diagnostic Approach to Pulmonary Hypertension in Premature Neonates

Bronchopulmonary dysplasia (BPD) is a form of chronic lung disease in premature infants following respiratory distress at birth. With increasing survival of extremely low birth weight infants, alveolar simplification is the defining lung characteristic of infants with BPD, and along with pulmonary hypertension, increasingly contributes to both respiratory morbidity and mortality in these infants. Growth restricted infants, infants born to mothers with oligohydramnios or following prolonged preterm rupture of membranes are at particular risk for early onset pulmonary hypertension. Altered vascular and alveolar growth particularly in canalicular and early saccular stages of lung development following mechanical ventilation and oxygen therapy, results in developmental lung arrest leading to BPD with pulmonary hypertension (PH). Early recognition of PH in infants with risk factors is important for optimal management of these infants. Screening tools for early diagnosis of PH are evolving; however, echocardiography is the mainstay for non-invasive diagnosis of PH in infants. Cardiac computed tomography (CT) and magnetic resonance are being used as imaging modalities, however their role in improving outcomes in these patients is uncertain. Follow-up of infants at risk for PH will help not only in early diagnosis, but also in appropriate management of these infants. Aggressive management of lung disease, avoidance of hypoxemic episodes, and optimal nutrition determine the progression of PH, as epigenetic factors may have significant effects, particularly in growth-restricted infants. Infants with diagnosis of PH are managed with pulmonary vasodilators and those resistant to therapy need to be worked up for the presence of cardio-vascular anomalies. The management of infants and toddlers with PH, especially following premature birth is an emerging field. Nonetheless, combination therapies in a multi-disciplinary setting improves outcomes for these infants.

BNP, troponin I, and YKL-40 as screening markers in extremely preterm infants at risk for pulmonary hypertension associated with bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is often complicated by pulmonary hypertension (PH). We investigated three biomarkers potentially suitable as screening markers for extremely preterm infants at risk of BPD-associated PH. In this prospective observational cohort study conducted in a tertiary neonatal intensive care unit, 83 preterm infants with BPD born <28-wk gestation and still inpatients at 36-wk corrected age received an echocardiogram and blood tests of B-type natriuretic peptide (BNP), troponin I, and YKL-40. Infants were analyzed according to echocardiographic evidence of tricuspid regurgitation (TR). Thirty infants had evidence of TR on echocardiogram at 36-wk corrected age. Infants with or without TR had similar baseline demographics: mean ± SD gestational age 26¹ ± 1² vs. 26¹ ± 1¹ wk and birth weight 830 ± 206 vs. 815 ± 187 g, respectively. There was no difference in duration of respiratory support. The right ventricular systolic pressure of infants with evidence of TR was 40 ± 16 mmHg. BNP was the only biomarker that proved to be significantly higher in infants with evidence of TR: median (interquartile range) serum level 54.5 (35-105) vs. 41.5 (30-59) pg/ml, P = 0.043. Subgroup analysis of infants with severe BPD requiring discharge on home oxygen or BPD-related mortality revealed similar results. There was no difference between groups for troponin I and YKL-40. In conclusion, increased serum levels of BNP were associated with evidence of TR at 36-wk corrected gestational age in extremely preterm infants, suggesting a potential role as a screening biomarker for BPD-associated PH.

Impact of pulmonary hypertension on neurodevelopmental outcome in preterm infants with bronchopulmonary dysplasia: a cohort study

OBJECTIVES

To evaluate the impact of pulmonary hypertension (PH) on long-term growth and neurodevelopmental outcomes of extremely preterm infants with bronchopulmonary dysplasia (BPD).

STUDY DESIGN

A single-center retrospective cohort of preterm infants born at <28 weeks gestational age from 2000 to 2011 was evaluated at 3 years of age. Growth and neurodevelopmental outcomes were compared among 3 groups: non-BPD, BPD without PH and BPD with PH. BPD was defined according to oxygen demand at 36 weeks postmenstrual age. PH was diagnosed by echocardiography during the neonatal intensive care unit stay.

RESULTS

Sixty-two infants without BPD, 60 with BPD without PH and 20 with BPD with PH were analyzed. Regardless of PH status, somatic growth was smaller in both BPD groups of infants than in non-BPD infants, with further reduction in the group having BPD with PH. Furthermore, a developmental quotient of <70 was more prevalent in the BPD infants with PH than in the BPD infants without PH (odds ratio (OR): 4.37; 95% confidence interval, CI: 1.16 to 16.5). Multivariate analysis demonstrated that BPD with PH was one of the independent perinatal risk factors for developmental quotient <70 at 3 years of age (OR: 4.94, 95% confidence interval: 1.06 to 24.1).

CONCLUSION

PH had an additional negative effect on long-term growth and neurodevelopmental outcomes of extremely preterm infants with BPD.

Pulmonary hypertension associated with acute or chronic lung diseases in the preterm and term neonate and infant. The European Paediatric Pulmonary Vascular Disease Network, endorsed by ISHLT and DGPK

Persistent pulmonary hypertension of the newborn (PPHN) is the most common neonatal form and mostly reversible after a few days with improvement of the underlying pulmonary condition. When pulmonary hypertension (PH) persists despite adequate treatment, the severity of parenchymal lung disease should be assessed by chest CT. Pulmonary vein stenosis may need to be ruled out by cardiac catheterisation and lung biopsy, and genetic workup is necessary when alveolar capillary dysplasia is suspected. In PPHN, optimisation of the cardiopulmonary situation including surfactant therapy should aim for preductal SpO2between 91% and 95% and severe cases without post-tricuspid-unrestrictive shunt may receive prostaglandin E1 to maintain ductal patency in right heart failure. Inhaled nitric oxide is indicated in mechanically ventilated infants to reduce the need for extracorporal membrane oxygenation (ECMO), and sildenafil can be considered when this therapy is not available. ECMO may be indicated according to the ELSO guidelines. In older preterm infant, where PH is mainly associated with bronchopulmonary dysplasia (BPD) or in term infants with developmental lung anomalies such as congenital diaphragmatic hernia or cardiac anomalies, left ventricular diastolic dysfunction/left atrial hypertension or pulmonary vein stenosis, can add to the complexity of the disease. Here, oral or intravenous sildenafil should be considered for PH treatment in BPD, the latter for critically ill patients. Furthermore, prostanoids, mineralcorticoid receptor antagonists, and diuretics can be beneficial. Infants with proven or suspected PH should receive close follow-up, including preductal/postductal SpO2measurements, echocardiography and laboratory work-up including NT-proBNP, guided by clinical improvement or lack thereof.

Association of BNP, NTproBNP, and early postnatal pulmonary hypertension in very preterm infants

OBJECTIVE

B-type natriuretic peptide (BNP) has been shown to correlate with pulmonary hypertension (PH) in term neonates with persistent pulmonary hypertension of the newborn or congenital diaphragmatic hernia, and in very preterm infants with bronchopulmonary dysplasia. This study investigated the potential association of BNP and N-terminal-pro-BNP (NTproBNP) and PH within the first 72 hr of life in very preterm infants.

METHODS

Preterm infants <32 weeks gestational age who received an echocardiogram within the first 72 hr of life were eligible. BNP and NTproBNP were sampled at the time of the echocardiogram. Right ventricular systolic pressure (RVSP) was calculated as a surrogate marker of PH. Simple and multiple linear regression analysis was performed to examine associations and potential confounding factors.

RESULTS

Sixty-one infants were included with a median (IQR) birth weight of 983 g (826-1,167) and a median (IQR) gestational age of 27(2) weeks (26(2) -28(6) ). There was no difference between BNP or NTproBNP levels for infants with or without measurable RVSP. There was no significant correlation of BNP and RVSP in multiple linear regression analysis (regression coefficient -0.0035 (95%CI: -0.020 to 0.013), P = 0.67). Also, NTproBNP and RVSP were not significantly correlated in multiple linear regression analysis (regression coefficient 0.0071 (95%CI: -0.019 to 0.033), P = 0.58).

CONCLUSION

B-type natriuretic peptides did not correlate with RVSP in the early postnatal period of very preterm infants. Pediatr Pulmonol. 2016;51:820-824. © 2016 Wiley Periodicals, Inc.

N-terminal pro-brain natriuretic peptide measurements in hemodynamically significant patent ductus arteriosus in preterm infants

OBJECTIVES

Evaluate the role of NT-proBNP levels in Preterm neonates suffering from PDA and used as a screening tool for predicting HsPDA and guiding physicians to consider early echocardiographic evaluation.

METHODS

This is a monocentric prospective blind study which was conducted at Arar Central Hospital, Ar'ar, Saudi Arabia, during the period between Jan 2014 to June 2014. Thirty-three (33) preterm infants born at less than 31 weeks of gestation or weighing less than 1200 g at birth infants were initially enrolled during a 6-month period. Blood samples were collected along with routine blood tests on days 1, 2, 3, and 7 of life for NT-proBNP analysis. Two echocardiographies were systematically performed on day two of life to ascertain about the status of Ductus Arteriosus.

RESULTS

The Plasma NT-proBNP levels were high on day one of life and decline from day three to day seven of life except in those infants with significant hsPDA. Plasma NT-proNBP levels on day 2 of infants in the HsPDA group were significantly higher (<0.001) than those in non-HsPDA group. Echocardiogram parameters indicates the significant difference (p<0.002) in Left Atrial and Aortic ratio (LA/AO), Interventricular septum thickness (P<0.03), Left ventricular posterior wall thickness (p<0.05), diastole PDA gradient (p<0.005) between HsPDA and non-HsPDA.

CONCLUSIONS

Plasma NT-proBNP level peaked during the first few days after birth and declined rapidly within a week. Therefore, its level may have a role as a screening tool to predict HsPDA and provide more information regarding its spontaneous closure or otherwise.

Management of hypoxemic respiratory failure and pulmonary hypertension in preterm infants

While diagnoses of hypoxemic respiratory failure (HRF) and pulmonary hypertension (PH) in preterm infants may be based on criteria similar to those in term infants, management approaches often differ. In preterm infants, HRF can be classified as 'early' or 'late' based on an arbitrary threshold of 28 postnatal days. Among preterm infants with late HRF, the pulmonary vascular abnormalities associated with bronchopulmonary dysplasia (BPD) represent a therapeutic challenge for clinicians. Surfactant, inhaled nitric oxide (iNO), sildenafil, prostacyclin and endothelin receptor blockers have been used to manage infants with both early and late HRF. However, evidence is lacking for most therapies currently in use. Chronic oral sildenafil therapy for BPD-associated PH has demonstrated some preliminary efficacy. A favorable response to iNO has been documented in some preterm infants with early PH following premature prolonged rupture of membranes and oligohydramnios. Management is complicated by a lack of clear demarcation between interventions designed to manage respiratory distress syndrome, prevent BPD and treat HRF. Heterogeneity in clinical phenotype, pathobiology and genomic underpinnings of BPD pose challenges for evidence-based management recommendations. Greater insight into the spectrum of disease phenotypes represented by BPD can optimize existing therapies and promote development of new treatments. In addition, better understanding of an individual's phenotype, genotype and biomarkers may suggest targeted personalized interventions. Initiatives such as the Prematurity and Respiratory Outcomes Program provide a framework to address these challenges using genetic, environmental, physiological and clinical data as well as large repositories of patient samples.

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.

Persistent Challenges in Pediatric Pulmonary Hypertension

Pulmonary hypertension and related pulmonary vascular diseases cause significant morbidities and high mortality and present many unique challenges toward improving outcomes in neonates, infants, and children. Differences between pediatric and adult disease are reflected in controversies regarding etiologies, classification, epidemiology, diagnostic evaluations, and therapeutic interventions. This brief review highlights several key topics reflecting recent advances in the field and identifies persistent gaps in our understanding of clinical pediatric pulmonary hypertension.

Biochemical Screening for Pulmonary Hypertension in Preterm Infants with Bronchopulmonary Dysplasia

BACKGROUND

Pulmonary hypertension (PH) in infants with bronchopulmonary dysplasia (BPD) is associated with increased morbidity and mortality. Elevated levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP) and decreased levels of amino acid precursors of nitric oxide (NO) have been associated with PH, but have not been studied in infants with PH secondary to BPD.

OBJECTIVE

The aim of this study was to identify a biochemical marker for PH in infants with BPD.

METHODS

Twenty infants, born at <27 weeks' gestational age (GA) and/or with a birth weight (BW) ≤750 g, who met the criteria for BPD at 36 weeks' corrected GA (CGA) were enrolled in this cross-sectional pilot study. A screening echocardiogram was conducted at 36-38 weeks' CGA and plasma NT-proBNP and amino acid levels were obtained within 1 week of the screening echocardiogram.

RESULTS

Five infants (25%) had echocardiographic evidence of PH. GA and BW were not significantly different between the 2 groups (a PH group and a No PH group). NT-proBNP was significantly elevated in the PH group (median 1,650 vs. 520 pg/ml; p = 0.001) but citrulline levels were significantly lower (median 21 vs. 36 μmol/l; p = 0.005). Arginine levels were not significantly different between the groups (median 78 vs. 79 μmol/l; p = 1).

CONCLUSION

NT-proBNP and the NO precursor citrulline may be cost-effective biochemical markers for screening for the presence of PH in preterm infants who have BPD. If validated in a larger study, such biochemical markers may, in part, replace PH screening echocardiograms in these patients.

B-type natriuretic peptide as a parameter for pulmonary hypertension in children. A systematic review

Pulmonary hypertension (PH) is a life-threatening disease with a high mortality rate and a broad variety of underlying etiologies. The current golden standard for diagnosing PH and monitoring efficiency of treatment is right heart catheterization. As an alternative, serum biomarkers have been suggested. Cardiac troponin T (TnT), brain natriuretic peptide (BNP), and NT-proBNP seem the most potential. The aim of this systematic review was to evaluate the current literature on the prognostic value of these biomarkers in children with PH and their usefulness as a diagnostic tool. A systematic literature search yielded 14 studies on patients ≤18 years with proven PH with (NT-pro)BNP or TnT as primary outcome. TnT is suggested to be a promising biomarker, but its usefulness in clinical practice has not been proven. The levels of (NT-pro)BNP seemed to be reliable within one PH category, but differed significantly between categories. NT-proBNP showed a good correlation with mortality and might have a prognostic value.

CONCLUSION

The lack of absolute levels makes (NT-pro)BNP unsuitable as a diagnostic marker, but in view of the relative changes, it could be used to monitor patients. Further investigation should explore differences in normal (NT-pro)BNP levels between the different categories of PH.

WHAT IS KNOWN

• Pulmonary hypertension is a life-threatening disease. Diagnosis can be challenging in children; the current diagnostic options-right heart catheterization and echocardiography-are invasive and/or investigator-dependent procedures. • Biomarkers could be useful in this context because they are investigator independent and easy to obtain through blood samples. Brain natriuretic peptide (BNP) and its N-terminal cleavage product (NT-proBNP) seem to be the most promising. The value of these biomarkers in the diagnostic approach of PH has already been investigated in adults, with promising results. Pediatric studies are still scarce. What is new: • The levels of BNP and NT-proBNP in pediatric patients differ strongly between the different categories of PH. Within the same category, the levels are more or less equal. • The relative changes could render them a prognostic marker in the follow-up of a certain individual patient. At this moment there is not enough evidence to rely on BNP or NT-proBNP in clinical treatment of patients with PH.

Diagnosing significant PDA using natriuretic peptides in preterm neonates: a systematic review

BACKGROUND AND OBJECTIVES

Echocardiogram is the gold standard for the diagnosis of hemodynamically significant patent ductus arteriosus (hsPDA) in preterm neonates. A simple blood assay for brain natriuretic peptide (BNP) or amino-terminal pro-B-type natriuretic peptide (NT-proBNP) may be useful in the diagnosis and management of hsPDA. Our objectives were to determine the diagnostic accuracy of BNP and NT-proBNP for hsPDA in preterm neonates and to explore heterogeneity by analyzing subgroups.

METHODS

The systematic review was performed as recommended by the Cochrane Diagnostic Test Accuracy Working Group. Electronic databases, conference abstracts, and cross-references were searched. We included studies that evaluated BNP or NT-proBNP (index test) in preterm neonates with suspected hsPDA (participants) in comparison with echocardiogram (reference standard). A bivariate random effects model was used for meta-analysis, and summary receiver operating characteristic curves were generated.

RESULTS

Ten BNP and 11 NT-proBNP studies were included. Studies varied by methodological quality, type of commercial assay, thresholds, age at testing, gestational age, and whether the assay was used to initiate medical or surgical therapy. Sensitivity and specificity for BNP at summary point were 88% and 92%, respectively, and for NT-proBNP they were 90% and 84%, respectively.

CONCLUSIONS

The studies evaluating the diagnostic accuracy of BNP and NT-proBNP for hsPDA varied widely by assay characteristics (assay kit and threshold) and patient characteristics (gestational and chronological age); therefore, generalizability between centers is not possible. We recommend that BNP or NT-proBNP assays be locally validated for specific patient population and outcomes, to initiate therapy or follow response to therapy.