Are B-type natriuretic peptide (BNP) and N-terminal-pro-BNP useful in neonates?

Utility of urinary NT-proBNP in congenital diaphragmatic hernia: a prospective pilot study

BACKGROUND

Echocardiography is the reference standard for diagnosing pulmonary hypertension (PH) and cardiac dysfunction (CD) in congenital diaphragmatic hernia (CDH). The use of an adjunct non-invasive biomarker would be invaluable. Plasma N-terminal brain Natriuretic Peptide (NT-proBNP) has been evaluated as a biomarker in CDH. Our objective was to investigate the utility of urinary NT-proBNP as an adjunct biomarker in CDH.

METHODS

Prospective observational study of neonates with CDH. Urinary NT-proBNP and its ratio to urinary creatinine (UNBCR) were analyzed at 24 h of life (HOL). Spearman's correlation was used to quantify the association between the urinary NT-proBNP with corresponding plasma concentrations. Logistic regression and receiver operating characteristic (ROC) curve analyses were used to examine urinary NT-proBNP and UNBCR's association with need for ECMO. The Kruskal-Wallis test was used to compare urinary NT-proBNP concentrations with echocardiography parameters of PH and CD.

RESULTS

Urinary NT-proBNP and UNBCR positively correlated with plasma concentrations. Patients with high right ventricular (RV) pressures had higher urinary NT-proBNP concentrations. Both urinary NT-proBNP and UNBCR concentrations increased with worsening left and right ventricular dysfunction on first postnatal echocardiogram.

CONCLUSION

We report the feasibility of urinary NT-proBNP as a non-invasive biomarker to assess PH and CD in CDH.

IMPACT STATEMENT

Non-invasive biomarkers are an important area of research in neonates as they have the potential to decrease the need for blood sampling, which may cause pain, stress, and induce iatrogenic anemia. Use of non-invasive biomarkers could be especially useful in congenital diaphragmatic hernia (CDH) who may need Extra-Corporeal Life Support (ECLS) for their management. We evaluated the potential utility of the urinary NT-proBNP in CDH. Plasma NT-proBNP has been studied in neonates with CDH; however, urinary NT-proBNP has not been explored, making this the first study to examine its potential as a biomarker.

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

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

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.

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.

Evaluation of Circulating Cardiovascular Biomarker Levels for Early Detection of Congenital Heart Disease in Newborns in Sweden

IMPORTANCE

Congenital heart disease (CHD) is the most common congenital malformation in humans worldwide. Circulating cardiovascular biomarkers could potentially improve the early detection of CHD, even in asymptomatic newborns.

OBJECTIVES

To assess the performance of a dried blood spot (DBS) test to measure the cardiovascular biomarker amino terminal fragment of the prohormone brain-type natriuretic peptide (NT-proBNP) levels in newborns and to compare DBS with standard EDTA analysis in control newborns during the first week of life.

DESIGN, SETTING, AND PARTICIPANTS

This diagnostic study was conducted in a single regional pediatric service in southern Sweden. Healthy, term neonates born between July 1, 2018, and May 31, 2019, were prospectively enrolled and compared against retrospectively identified newborns with CHD born between September 1, 2003, and September 30, 2019. Neonates who required inpatient treatment beyond the standard postnatal care were excluded.

EXPOSURE

New DBS test for NT-proBNP quantification in newborns that used 3 μL of blood vs the current screening standard.

MAIN OUTCOMES AND MEASURES

Performance of the new test and when combined with pulse oximetry screening was measured by receiver operating characteristic curve analysis. Performance of the new test and EDTA screening was compared using Pearson linear correlation analysis.

RESULTS

The DBS samples of 115 neonates (81 control newborns and 34 newborns with CHD, of whom 63 were boys [55%] and the mean [SD] gestational age was 39.6 [1.4] weeks) were analyzed. The new NT-proBNP test alone identified 71% (n = 24 of 34) of all CHD cases and 68% (n = 13 of 19) of critical CHD cases as soon as 2 days after birth. Detection of any CHD type improved to 82% (n = 28 of 34 newborns) and detection of critical CHD improved to 89% (n = 17 of 19 newborns) when combined pulse oximetry screening and NT-proBNP test results were used. Performance of the NT-proBNP test was excellent when control newborns were matched to newborns with CHD born between July 1, 2018, and May 31, 2019 (area under the curve, 0.96; SE, 0.027; 95% CI, 0.908-1.0; asymptotic P < .05).

CONCLUSIONS AND RELEVANCE

This study found that NT-proBNP assay using minimal DBS samples appears to be timely and accurate in detecting CHD in newborns and to discriminate well between healthy newborns and newborns with various types of CHD. This finding warrants further studies in larger cohorts and highlights the potential of NT-proBNP to improve neonatal CHD screening.

Cardiovascular biomarkers in the evaluation of patent ductus arteriosus in very preterm neonates: A cohort study

BACKGROUND

The evaluation of the patent ductus arteriosus (PDA) in the very premature neonate is a challenge. Echocardiography provides an interpretation of the hemodynamic condition. It is however, only a snapshot. Biomarkers may represent a physiological response to the hemodynamic alterations brought on by the PDA and may add to the identification of the clinical significant PDA.

AIM

To investigate the association between mid regional proadrenomodulin (MR-proADM), N-terminal pro b-type natriuretic peptide (NT-proBNP), mid regional pro-atrial natriuretic peptide (MR-proANP), C-terminal pro endothelin-1 (CT-proET1) and copeptin and echocardiographic measures of PDA.

STUDY DESIGN

Cohort study with echocardiography performed on day 3 and 6. Blood samples from day 3.

SUBJECT

139 consecutive neonates born at a gestational age <32 weeks.

OUTCOME MEASURES

The main outcomes were presence of a PDA day 3 and 6, PDA diameter, left atrium to aorta ratio (LA:Ao-ratio), and descending aorta diastolic flow (DADF).

RESULTS

Adjusted plasma levels of all investigated biomarkers, except CT-proET1, were found to be associated with both PDA diameter and LA:Ao-ratio, and also the presence of a large PDA. CT-proET1 and copeptin was found to be associated with abnormal DADF. Using pre-specified cut-off values NT-proBNP and MR-proANP day 3 seemed to be of value in identifying a large PDA day 3 and 6 in very preterm neonates.

CONCLUSION

Among the investigated biomarkers NT-proBNP and MR-proANP performed best in relation to echocardiographic markers of PDA severity in very preterm neonates.

Pathophysiology and molecular signalling in pediatric heart failure and VAD therapy

Heart Failure (HF) is a progressive clinical syndrome characterized by molecular and structural abnormalities that result in impaired ventricular filling and a reduced blood ejection. In pediatric patients, HF represents an important cause of morbidity and mortality, but underlying cause, presentation and disease course remains unclear in many cases. It is evident that a child is not a "small adult" and findings are not comparable. The adoption of a standardized clinical and surgical tools as well as increased biomolecular research and therapeutic trials targeting pediatric patients with HF would greatly improve the management of this special class of patients. This review examines the most current information about the pathophysiology and molecular mechanisms related to HF in children to identify gaps in our knowledge base to further improve clinical care and outcomes.

Circulating Forms of B-Type Natriuretic Peptide in Very Preterm Infants

BACKGROUND

B-type natriuretic peptide (BNP) is a cardiac hormone released with an N-terminal fragment (NTproBNP) under conditions of ventricular pressure or volume overload. BNP has been proposed for use as a biomarker of cardiac dysfunction in premature infants in the setting of hemodynamically significant patent ductus arteriosus (HsPDA) and bronchopulmonary dysplasia (BPD). In adult settings the presence of proBNP and glycosylated isoforms may affect assay interpretation. However, there are limited data on how immature preterm physiology may affect BNP or NTproBNP levels and no published data on post-translational BNP processing in premature infants.

METHODS

Pooled serial plasma samples from preterm infants born at less than 30 weeks gestation were analyzed for BNP congeners using Luminex® assay and high performance liquid chromatography. Samples were grouped according to clinical status: Group 1, no HsPDA and no BPD, Group 2 HsPDA and no/mild BPD, Group 3 HsPDA and moderate/severe BPD.

RESULTS

Plasma from 15 infants was analyzed, and across all three groups NTproBNP predominated with minimal amounts of other isoforms; no glycosylation was detected.

CONCLUSIONS

NTproBNP appears to be the predominant isoform across each of our clinical groups in our pooled sample analysis with no evidence of significant glycosylation. This suggests NTproBNP is likely to be a robust marker in this clinical setting.

N-terminal pro-brain natriuretic peptide as a biomarker for differentiating cardiac and pulmonary disease in term neonates with respiratory distress

Objective

Brain natriuretic peptide (BNP) is synthesized in the cardiac ventricles and released in response to volume or pressure load. The aim of the study was to determine whether plasma level of N-terminal pro BNP (NT-pro BNP) can distinguish between cardiac and pulmonary disease (PD) among neonates with respiratory distress (RD).

Patients and methods

The study included 48 term neonates in the first month of life with signs of RD. They were recruited from Neonatal Intensive Care Unit of Al-Galaa Teaching Hospital. Twenty-six healthy neonates were included as a control group. The degree of RD was assessed using Silverman–Anderson score. Chest X-ray, echocardiography, and laboratory measurement of NT-pro BNP were performed.

Results

According to the underlying disease, neonates with RD were divided into 28 neonates with PD and 20 neonates with congenital heart disease (CHD). Regardless the etiology of RD, NT-pro BNP was significantly higher in the RD group than in the control (p = 0.001). There was a significant difference between and within the three groups regarding NT-pro BNP (p = 0.001). NT-pro BNP was significantly higher in the CHD group than in the PD group (p = 0.001). There was a significant difference between and within RD subgroups. The NT-pro BNP is a very useful test for identification of CHD in neonates with RD. Area under the receiver operating characteristic curve for CHD was 0.857 (p = 0.01), sensitivity 66%, specificity 85%, and cutoff point was 24.5 pg/mL. The area under the curve for PD was 0.646 (p = 0.1) with poor sensitivity and specificity, indicating that NT-pro BNP is a poor test for identification of PD in neonates with RD.

Conclusion

Term neonates with RD have increased plasma levels of NT-pro BNP. NT-pro BNP is a very good test for identification of CHD in neonates with RD, in comparison with PD. Therefore, plasma NT-pro BNP can be used to differentiate between cardiac and pulmonary cause of RD.

Serum and Urinary N-Terminal Pro-brain Natriuretic Peptides as Biomarkers for Bronchopulmonary Dysplasia of Preterm Neonates

Bronchopulmonary dysplasia (BPD) is a common cause of respiratory illness in preterm newborns with high morbidity and mortality rates. At present, there are no early prognostic biomarkers that can be used in clinical practice to predict the development of BPD. In this review, we critically appraise evidence regarding the use of serum N-terminal pro-brain natriuretic peptide (NTproBNP) levels as a biomarker for BPD in neonates. Furthermore, we summarize studies assessing the feasibility of urinary NTproBNP levels as a non-invasive method to predict BPD in preterm infants. Multiple studies reported a strong association between NTproBNP serum levels and the onset of BPD. For urinary NTproBNP there is scarce evidence showing an association with BPD. Given the promising data obtained by preliminary studies, further assessment of this biomarker in both serum and urine is needed. Standardized reference values should be defined before conducting any further clinical studies.

NOD-like receptor protein 3 and high mobility group box-1 are associated with prognosis of patients with congenital heart disease

Objective

To investigate the association between plasma levels of nucleotide-binding oligomerization domain-like (NOD)-like receptor protein 3 (NLRP3) and high mobility group box-1 (HMGB1) and their prognostic significance in neonatal patients with congenital heart disease (CHD).

Methods

This study enrolled neonatal patients with CHD and collected their demographic and clinical data. Plasma concentrations of NLRP3 and HMGB1 were measured using enzyme-linked immunosorbent assays. Spearman’s analysis was used to determine the correlation between NLRP3 and HMGB1 levels. The association between NLRP3 and HMGB1 levels and 2-year survival and mortality were evaluated using Kaplan–Meier curve and logistic regression analyses.

Results

A total of 84 neonatal patients with CHD were included in the study. Plasma NLRP3 and HMGB1 levels were significantly higher in deceased patients compared with those that survived. There was a positive correlation between NLRP3 and HMGB1 levels in neonatal patients with CHD. Patients with elevated levels of NLRP3 and HMGB1 showed significantly lower 2-year survival and higher mortality rates compared with those with lower NLRP3 and HMGB1 levels.

Conclusion

Neonatal patients with CHD and a poor prognosis had higher NLRP3 and HMGB1 levels, which suggests that these might be potential biomarkers of CHD prognosis.

Cardiovascular Biomarkers in Amniotic Fluid, Umbilical Arterial Blood, Umbilical Venous Blood, and Maternal Blood at Delivery, and Their Reference Values for Full-Term, Singleton, Cesarean Deliveries

Background: Several cardiovascular biomarkers have regulatory functions in perinatal physiology. Aim: This study aimed to analyze the feto-maternal distribution pattern of biomarkers in samples of amniotic fluid, umbilical arterial blood, umbilical venous blood, and maternal blood samples, and to establish reference values. Each linked sample set consisted of the combined samples obtained in an individual pregnancy. Study design: We performed a prospective, observational, cross-sectional, single-center study. Subjects: The sample cohort included 189 neonates who were born to 170 mothers. A total of 162/189 neonates were full term and 129/189 were delivered by elective cesarean section. Outcome measures: Midregional pro-adrenomedullin (MRproADM [nmol/L]), midregional pro-atrial natriuretic peptide (MRproANP [pmol/L]), brain natriuretic peptide (BNP [pg/mL]), N-terminal pro-brain natriuretic peptide (NTproBNP [pg/mL]), copeptin [pmol/L], and high-sensitive troponin I (hsTnI [pg/mL]) levels were measured. Results: In singleton, full-term, primary cesarean deliveries (n = 91), biomarker levels (median, [IQR]) at delivery were as follows. MRproADM levels in umbilical arterial blood/umbilical venous blood/amniotic fluid/maternal blood were 0.88 (0.20)/0.95 (0.18)/2.80 (1.18)/1.10 (0.54), respectively. MRproANP levels were 214.23 (91.38)/216.03 (86.15)/0.00 (3.82)/50.67 (26.81), respectively. BNP levels were 14.60 (25.18)/22.08 (18.91)/7.15 (6.01)/6.20 (18.23), respectively. NTproBNP levels were 765.48 (555.24)/816.45 (675.71)/72.03 (55.58)/44.40 (43.94), respectively. Copeptin levels were 46.17 (290.42)/5.54 (9.08)/9.97 (7.44)/4.61 (4.59), respectively. Levels of hsTnI were 6.20 (4.25)/5.60 (5.01)/0.45 (1.73)/2.50 (2.40), respectively. Conclusion: We determined reference values for biomarkers in term neonates delivered by primary cesarean section in amniotic fluid, umbilical arterial and venous blood, and maternal blood. Biomarkers in the fetal circulation appear to be of primary fetal origin, except for MRproADM.

B-type natriuretic peptide reference interval of newborns from healthy and pre-eclamptic women: a prospective, multicentre, cross-sectional study

OBJECTIVE

To define and compare the reference interval of B-type natriuretic peptide (BNP) in healthy newborns (HN) from healthy mothers and with severe pre-eclampsia.

DESIGN

Prospective, multicentre, cross-sectional study.

SETTING

Four obstetric wards of second-level academic hospitals.

PARTICIPANTS

167 HN, from 146 healthy and 21 severe pre-eclamptic women. We included newborns from healthy mothers with full-term pregnancies (38 to 42 gestational weeks), who received adequate prenatal care and who had Apgar scores ≥7 at 0 and 5 min. Newborns with chromosomopathies identified during prenatal consultations, those with respiratory distress and those with cardiac or pulmonary disease detected in the first paediatric evaluation were excluded from this study. In the group of pre-eclamptic women, we considered the same inclusion criteria, but the patients also had to meet the diagnostic criteria for pre-eclampsia with severity features, according to the American College of Obstetricians and Gynaecologists guidelines. The same exclusion criteria used for the healthy group were applied to the pre-eclampsia-associated newborn.

INTERVENTIONS

A single blood sample from the umbilical cord artery after delivery (vaginal or caesarean section).

PRIMARY OUTCOME

Reference level of BNP in HN.

RESULTS

In the HN group, the median BNP was 12.15 pg/mL (IQR 7.7-16.8 pg/mL) and in the pre-eclamptic group 20.8 pg/mL (IQR 5.8-46.5 pg/mL). The reference interval for BNP in HN was 5pg/mL (95% CI 5 to 5) to 34 pg/mL (95% CI 28.4 to 38.8). We identified higher expression of BNP in newborns from pre-eclamptic women overall (p=0.037, r=0.16) and in newborns exposed to stress conditions, such as complications during labour and delivery (p=0.004, r=0.33).

CONCLUSIONS

In HN, BNP concentrations at birth were lower than reported in other similar populations. In neonates with stress conditions, the higher expression of this biomarker establishes another possible link between stress and the cardiovascular response.

TRIAL REGISTRATION NUMBER

NCT02574806; Pre-results.

Correlation of B-type natriuretic peptide levels and echocardiographic parameters in preterm infants with patent ductus arteriosus

Purpose

This study aimed to evaluate the correlation, according to postnatal age, between plasma B-type natriuretic peptide (BNP) levels and echocardiographic parameters for the assessment of patent ductus arteriosus (PDA) in preterm infants with respiratory distress.

Methods

We enrolled 42 preterm infants with respiratory distress who underwent serial echocardiographic evaluation with simultaneous plasma BNP measurements until ductal closure. The correlations between BNP levels and the following 4 representative echocardiographic parameters were studied: diameter of the ductus arteriosus (DA), ratio of the left atrial diameter to the aortic diameter (LA/Ao), ratio of the PDA diameter to the infant's left pulmonary artery diameter (PDA/LPA), and the antegrade diastolic flow of LPA (DFLPA).

Results

BNP levels were significantly correlated to the magnitude of the ductal shunt, comprising the DA diameter, PDA/LPA ratio, LA/Ao ratio, and antegrade DFLPA for the overall study period. The earliest significant correlation, starting from postnatal day 2, was observed between the LA/Ao ratio and BNP levels. The PDA/LPA ratio and the antegrade DFLPA showed significant correlations with BNP levels postnatal day 3 onward, and with the DA diameter, postnatal day 5 onward.

Conclusion

BNP levels and echocardiographic parameters showed a positive correlation, but the significance of the correlations differed according to the postnatal age, especially during the first few days of life.

Amino-Terminal proB-Type Natriuretic Peptide Levels in the Umbilical Cord Blood of Neonates Differ According to the Type of Prenatally Diagnosed Congenital Heart Disease

The aim of this study was to investigate differences in amino-terminal proB-type natriuretic peptide (NT-proBNP) levels in the cord blood of neonates according to the type of congenital heart disease (CHD) and to evaluate the usefulness of NT-proBNP as a prognostic marker. We included 76 neonates with prenatally diagnosed CHD and 45 controls without CHD. Neonates were classified into five groups based on echocardiographic findings. The levels of NT-proBNP in the cord blood were examined and analyzed according to the neonatal outcomes. The levels of NT-proBNP were significantly elevated in the cord blood of neonates with CHD compared with that in the cord blood of controls. The levels of NT-proBNP in the group with right ventricular outflow tract obstruction without a ventricular septal defect were significantly increased compared to that in the other groups. The neonates that required acute surgical correction had higher levels of NT-proBNP in the cord blood, though they were not statistically significant. Meanwhile, NT-proBNP levels in the cord blood of neonates with functional single ventricle were significantly higher than that in the cord blood of those with functional biventricles. Significant differences in the levels of NT-proBNP between survivors and nonsurvivors were observed within 1 year of birth. In this study, we found that the levels of NT-proBNP in the cord blood of neonates with CHD were higher than the levels in controls. This finding was striking in the group with right ventricular outflow tract obstruction, and it was associated with surgery for functional single ventricle and 1-year survival.

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.

Neonatal cardiac dysfunction in intrauterine growth restriction

BACKGROUND

The early postnatal cardiovascular consequences of intrauterine growth restriction (IUGR) have not been completely elucidated. This study aimed to evaluate the effect of IUGR on neonatal myocardial function and cardiovascular adaptation to extrauterine life.

METHODS

Conventional and tissue Doppler echocardiographic parameters were compared on the second and fifth postnatal day between 30 IUGR and 30 appropriate-for-gestational age (AGA) neonates.

RESULTS

IUGR neonates presented relative interventricular septum (IVS) hypertrophy (IVS to left ventricular (LV) posterior wall diastolic ratio: median IUGR-AGA difference of 0.05 (interquartile range: 0.04-0.06); P = 0.020), relative LV dilatation (wall thickness to end-diastolic LV dimension difference of 0.12 (0.06-0.16); P = 0.012), and increased left myocardial performance index (MPI difference of 0.19 (0.05-0.28); P = 0.012). Repeated measurements ANOVA revealed a different pattern of change in LV stroke volume (LVSV; P < 0.001), LV cardiac output (LVCO; P < 0.001), MPI (P < 0.001), and heart rate (HR; P = 0.025) between AGA and IUGR infants. From the second to the fifth postnatal day, AGA neonates presented a decrease in MPI and HR with an increase in LVSV and LVCO. IUGR neonates failed to achieve similar changes in MPI, HR, and LVSV, whereas their LVCO decreased.

CONCLUSION

IUGR neonates present changes in cardiac morphology and subclinical myocardial dysfunction, which may result in an altered pattern of cardiovascular adaptation to extrauterine life.

N-terminal pro-brain natriuretic peptide levels in monochorionic diamniotic twins with selective intrauterine growth restriction

OBJECTIVE

To compare serum N-terminal pro-brain natriuretic peptide levels at birth between monochorionic diamniotic twins with and without selective intrauterine growth restriction.

STUDY DESIGN

Blood samples were collected from 73 monochorionic diamniotic twins without twin-to-twin transfusion syndrome. Two groups were studied on the basis of fetal ultrasonographic findings: 16 twins with and 57 twins without selective intrauterine growth restriction. Selective intrauterine growth restriction was defined as an estimated fetal weight below the 10th percentile in one twin at 18 to 26 weeks of gestation. Serum N-terminal pro-brain natriuretic peptide levels were measured.

RESULT

Serum N-terminal pro-brain natriuretic peptide levels in monochorionic diamniotic twins with selective intrauterine growth restriction were significantly higher than in those without selective intrauterine growth restriction. Selective intrauterine growth restriction was independently associated with increased N-terminal pro-brain natriuretic peptide levels.

CONCLUSION

N-terminal pro-brain natriuretic peptide levels at birth are elevated in monochorionic diamniotic twins with selective intrauterine growth restriction.

B-type natriuretic peptide for assessment of haemodynamically significant patent ductus arteriosus in premature infants

Aim: Haemodynamically significant patent ductus arteriosus (hsPDA) is frequently observed in premature infants. This study was conducted to explore whether the blood BNP can be a valuable biomarker to assess the necessity of treatment for hsPDA in premature infants.

Methods: Serial measurements of the blood BNP were performed during the first 5 days of life in premature infants with hsPDA (Group I) and those without hsPDA (Group N). The definition of the hsPDA was the PDA requiring treatment, such as indomethacin administration and/or surgical ligation.

Results: Forty-six subjects were enrolled. Compared with Group N, Group I showed significantly higher level of blood BNP at postnatal 24–96 h and demonstrated the peak value at postnatal 24–48 h. With the ROC curve using the data at postnatal 24–48 h in Group I, we deduced the predictive value of 250 pg/mL of blood BNP for indomethacin treatment. Similarly, with the ROC curve using the maximal value of blood BNP within the first 5 days of life, the predictive value of 2000 pg/mL for surgical ligation was deduced.

Conclusions: Blood BNP during early postnatal period can be a useful biomarker to assess the necessity of treatment for hsPDA in premature infants.

Use of cardiac biomarkers in neonatology

Cardiac biomarkers are used to identify cardiac disease in term and preterm infants. This review discusses the roles of natriuretic peptides and cardiac troponins. Natriuretic peptide levels are elevated during atrial strain (atrial natriuretic peptide (ANP)) or ventricular strain (B-type natriuretic peptide (BNP)). These markers correspond well with cardiac function and can be used to identify cardiac disease. Cardiac troponins are used to assess cardiomyocyte compromise. Affected cardiomyocytes release troponin into the bloodstream, resulting in elevated levels of cardiac troponin. Cardiac biomarkers are being increasingly incorporated into clinical trials as indicators of myocardial strain. Furthermore, cardiac biomarkers can possibly be used to guide therapy and improve outcome. Natriuretic peptides and cardiac troponins are potential tools in the diagnosis and treatment of neonatal disease that is complicated by circulatory compromise. However, clear reference ranges need to be set and validation needs to be carried out in a population of interest.

Can a clinical decision rule help ductus arteriosus management in preterm neonates?

AIM

Patent ductus arteriosus (DA) occurs frequently in premature neonates with respiratory distress syndrome. We assessed a combination of clinical, biological and echocardiographic parameters to derive a decision rule for selecting candidates for treatment based on the criteria in use in our unit.

METHODS

Hundred and forty neonates with a mean (SD) gestational age of 28 (2.3) weeks and a mean birth weight of 1159 (386) g, all requiring invasive ventilation with FiO(2) > 0.3 or catecholamines for severe hypotension, were assessed prospectively using echocardiography in conjunction with N-terminal pro-B-type natriuretic peptide (NTpBNP) levels within 24-72 h of birth. Independent predictors of DA treatment were identified with univariate analysis and combined in a clinical decision rule.

RESULTS

Early treatment of significant DA was adopted for 26 (18.6%) neonates. A clinical decision rule suggesting treatment in patients with NTpBNP > 8500 pg/mL, ductal diameter >1.5 mm and, for infants with a birth weight > 830 g, left pulmonary artery end-diastolic velocity >0.20 m/sec showed 88% sensitivity and 94% specificity.

CONCLUSIONS

A decision rule using realistic and/or commonly used parameters for significant patent ductus arteriosus assessment could be derived. External validation of this rule is needed before any application.

The evaluation of diagnostic role of cardiac troponin T (cTnT) in newborns with heart defects

Heart diseases are a significant cause of morbidity and mortality in newborns. Diagnostic methods are often not sufficient or, in many cases, cannot be used. There is a great advance in medical knowledge concerning biomarkers in the diagnosis of circulatory system in adult patients. Among them, cardiac troponins play the main role. In current literature, there is not enough data concerning the possibility of using them in neonatal cardiac diagnostics. Aim of the Study. To evaluate diagnostic usefulness of cTnT in correlation with other markers of circulatory failure and myocardial damage in newborns with heart defects. Patients and Methods. The study involved 83 newborns up to 46 weeks of postmenstrual age. The exclusion criteria were severe perinatal asphyxia and presence of severe noncardiac diseases. Patients were divided into 2 main groups: group I—54 patients with congenital heart defects (CHDs), and group II (control)—29 healthy neonates. All patients underwent detailed examination of circulatory system. Cardiac troponin T (cTnT) concentrations were evaluated by Roche CARDIAC T Quantitive test. Results. Performed studies revealed that cTnT levels in newborns with heart pathology were significantly higher than in healthy ones. However, cTnT concentrations in patients with CHD did not correlate with clinical symptoms of heart failure, nor with echocardiographic markers of LV function. Type of heart defect did not influence cTnT levels as well. Only hemodynamic significance evaluated by echocardiography influenced the cTnT levels with statistical significance. Conclusions. (1) Statistically significant differences in cTnT levels between newborns with heart defects and healthy subjects were shown. (2) CTnT levels in newborns with heart defects refer only to hemodynamic significance of the defect.

Diagnosis of the preterm patent ductus arteriosus: clinical signs, biomarkers, or ultrasound?

The current uncertainty in relation to treatment of the preterm patent ductus arteriosus reflects limitations to our understanding of the pathophysiology of ductal shunting, most particularly which ducts matter to which babies and when they matter. Doppler ultrasound offers a pragmatic tool with which to assess ductal patency and shunt significance and to allow prediction of spontaneous and therapeutic closure. Biomarkers, such as B-type natriuretic peptide, and clinical signs may have a diagnostic role where ultrasound is not available and also possibly as an adjunct to echocardiography in determining the pathophysiological impact of a ductal shunt in an individual baby.

Cardiac biomarkers in neonatal hypoxic ischaemia

Following a perinatal hypoxic-ischaemic insult, term infants commonly develop cardiovascular dysfunction. Troponin-T, troponin-I and brain natriuretic peptide are sensitive indicators of myocardial compromise. The long-term effects of cardiovascular dysfunction on neurodevelopmental outcome following perinatal hypoxic ischaemia remain controversial. Follow-up studies are warranted to ensure optimal cardiac function in adulthood.

CONCLUSION

Cardiac biomarkers may improve the diagnosis of myocardial injury, help guide management, estimate mortality risk and may also aid in longterm neurodevelopmental outcome prediction following neonatal hypoxic-ischaemia.

B-type natriuretic Peptide assay for the diagnosis and prognosis of patent ductus arteriosus in preterm infants

BACKGROUND AND OBJECTIVES

Patent ductus arteriosus (PDA) is a significant cause of morbidity and mortality in preterm infants. Measurement of plasma B-type natriuretic peptide (BNP) has been reported to be a useful bedside screening tool for the presence of hemodynamically significant PDA (hsPDA) in neonates. This study was conducted to investigate the usefulness of a BNP assay as a biochemical marker for the diagnosis of hsPDA and predictive biomarker of the response to indomethacin in preterm infants.

SUBJECTS AND METHODS

Preterm infants born at <37 weeks' gestational age were prospectively enrolled within 24 hours of birth. Plasma BNP levels were measured on days 1, 4, and 7. Significant PDA was diagnosed by large ductal flow with left to right shunt on color Doppler echocardiography, along with clinical features of PDA. Following that, hsPDA was treated with indomethacin.

RESULTS

A total of 28 preterm infants were prospectively enrolled in this study. Seven infants with PDA had higher on day 4 plasma BNP values (median 654.68 pg/mL; range 428.29-1280.00) compared to the control group (median 124.52 pg/mL; range 37.21-290.49). The area under the receiver operator characteristic curve for the detection of hsPDA was high: 0.998 (95% confidence interval: 0.995-1.002). The cutoff of BNP concentration for the diagnosis of hsPDA was determined to be 412 pg/mL (sensitivity: 100%; specificity: 95%).

CONCLUSION

B-type natriuretic peptide can be a useful biomarker for the screening and diagnosis of PDA in preterm infants. Serial BNP measurements are valuable for assessing the clinical course and indomethacin responsiveness of PDA.

B-type natriuretic peptide and rebound during treatment for persistent pulmonary hypertension

OBJECTIVE

To investigate whether serum B-type natriuretic peptide (BNP) is a useful biomarker in evaluating the course of persistent pulmonary hypertension of the newborn (PPHN) and the effectiveness of treatment.

STUDY DESIGN

Prospective follow-up study of infants with clinical and echocardiographic signs of PPHN, who were treated with inhaled nitric oxide (iNO). Of 24 patients with PPHN who were treated, serum BNP levels were determined longitudinally in 21. BNP levels were compared between infants with (n = 6) and without rebound PPHN (n = 15).

RESULTS

BNP levels in all infants with PPHN were not significantly different at the initial start of iNO. BNP levels decreased in both groups during iNO treatment. In the infants in whom rebound PPHN developed after weaning from iNO, a significantly higher increase was found in BNP (283 pmol/L to 1232 pmol/L) compared with that in infants without rebound (98 pmol/L to 159 pmol/L). This occurred before the onset of clinical deterioration. BNP again decreased significantly after iNO treatment was restarted.

CONCLUSIONS

BNP, a biomarker of cardiac ventricular strain, proved to be useful in evaluating the efficacy of PPHN treatment, and moreover, BNP helps to predict a rebound of PPHN.

Cardiac biomarkers as indicators of hemodynamic adaptation during postasphyxial hypothermia treatment

BACKGROUND

Little is known about the effects of hypothermia on the cardiovascular system in term newborns with neonatal encephalopathy.

OBJECTIVES

To evaluate whether mild hypothermia for neonatal encephalopathy is cardioprotective as indicated by the cardiac biomarkers cardiac troponin I (cTnI) and B-type natriuretic peptide (BNP).

METHODS

This was an observational cohort study of infants treated for perinatal asphyxia. In infants, mild total body hypothermia treatment of 33.5°C during 72 h was initiated (n = 20). Samples of cTnI and BNP were collected before the start of hypothermia, at 24 and 48 h after birth, and after rewarming (84 h). BNP and cTnI values were then compared with BNP and cTnI values of asphyxiated infants not treated with hypothermia (n = 28).

RESULTS

No differences were found between the groups in clinical patient characteristics or inotropic support. The hypothermia-treated patients seemed to be clinically more affected (5-min Apgar score, p < 0.05; umbilical artery pH, p = 0.08), but showed similar encephalopathy scores. Significantly lower values for BNP were found in hypothermia- compared to nonhypothermia-treated infants at 48 h and at normothermia after rewarming [144 pmol/l (95-286) vs. 75 pmol/l (45-143), 182 pmol/l (73-341) vs. 43 pmol/l (24-163)]. No differences were found for cTnI concentrations between both groups.

CONCLUSIONS

The raised, but similar, cTnI values between hypothermia- and nonhypothermia-treated infants indicate similar myocardial damage in both groups. The lower BNP levels during hypothermia treatment suggest that hypothermia after perinatal asphyxia exerts a beneficial effect on cardiac function.

Clinical relevance of time course of BNP levels in neonates with congenital heart diseases

INTRODUCTION

The aim of this study is to better characterize the time courses of BNP levels throughout the first days of life in larger populations of neonate and infant with or without congenital heart diseases (CHD) in order to increase the diagnostic accuracy of BNP assay in pediatric patients with CHD.

MATERIALS AND METHODS

BNP was measured by an automated platform (Triage BNP reagents, ACCESS Immunoassay Systems, Beckman Coulter, Inc., Fullerton, CA 92835) in 218 neonates and infants with different CHD; 222 healthy children, matched for age, served as controls.

RESULTS

BNP values were significantly higher (P<0.001) in the whole group of CHD patients (median 1029.8 ng/L, range 25-20,152 ng/L) than in controls (median 149.5 ng/L, range 9-866 ng/L). A different trend between BNP values and age was observed in healthy subjects and CHD patients. After an initial increase within the first 4 days of life, BNP values in CHD patients tend to stabilize to high values in the following days. On the contrary, in control subjects a peak of BNP levels was observed in the second or third day, followed by a progressive decrease. Therefore, the diagnostic accuracy of BNP assay, calculated in the samples collected in the first four days of life (AUC of ROC analysis 0.86, 95% CI 0.83-0.90) was significantly lower (P<0.0001) compared to samples collected from 5 days to 30 days of life (AUC 0.97, 95% CI 0.95-0.99). Optimal cut-off values for BNP assay, as calculated by ROC analysis, were also age-dependent (cutoff for the first 4 days of life: 363.5 ng/L; cutoff values from 5 to 30 days of life: 109.5 ng/L).

CONCLUSIONS

Our study demonstrates that differences in time-courses of BNP values between newborns with and without CHD throughout the first days of life clearly affect the diagnostic accuracy of BNP assay. Indeed, the diagnostic accuracy of BNP assay in discriminating between healthy newborns and CHD patients progressively increases after the 4th day of life. As a result, also cutoff values of BNP assay greatly change throughout the first days of life. However, decision values of BNP assay are strongly method-dependent, consequently clinicians should give great care to compare results obtained by different laboratories, especially when different methods are used.

N-terminal-pro-brain natriuretic peptide: a guide for early targeted indomethacin therapy for patent ductus arteriosus in preterm Infants

AIM

To determine whether N-terminal-pro-brain natriuretic peptide (NT-proBNP) level could be an effective guide for early targeted indomethacin therapy for patent ductus arteriosus (PDA) in preterm infants.

METHODS

An interventional study involved preterm infants, born at <33 weeks of gestation, who had plasma NT-proBNP levels obtained at day 2 of life. Indomethacin therapy was given if plasma NT-proBNP level was ≥10,180 pg/mL, the cut-off for predicting hemodynamic significant PDA (hsPDA). Echocardiograms were performed within 6 h at the time of plasma NT-proBNP collection and again at day 7, or whenever clinical hsPDA was suspected. Primary outcomes were the incidence of later hsPDA and unnecessary exposure rate to indomethacin.

RESULTS

Fifty infants were enrolled. On day 2, 19 (38%) infants had plasma NT-proBNP above the cut-off and received indomethacin therapy; none of them developed later hsPDA, while 1 of 31 infants with NT-proBNP below the cut-off level developed clinical hsPDA. Unnecessary exposure to indomethacin occurred in two infants (11%). Overall, no enrolled infants had either reopening of ductus or PDA ligation.

CONCLUSION

Using NT-proBNP level on day 2 as a guide for early targeted indomethacin therapy reduced later onset of hsPDA and the number of unnecessary exposures to indomethacin.

N-terminal pro-brain natriuretic peptide level as a screening tool for cardiac involvement in paediatric diseases of extracardiac origin

BACKGROUND

Serum concentrations of N-terminal natriuretic pro-brain natriuretic peptide (NT-proBNP) correlate well with the severity of cardiac disease in children and adults. There are also paediatric illnesses of extracardiac origin that may cause deterioration of the cardiac function in some patients (pts). A high NP level can signify a concomitant cardiac involvement in respiratory distress, or secondary to a systemic disease.

OBJECTIVE

To assess the potential of NT-proBNP as a screening tool for cardiac involvement in paediatric diseases of extracardiac origin.

METHODS

A literature search was performed in PubMed for the relevant studies with the subject brain natriuretic peptide (BNP) and NT-proBNP from 1995 to 2010 with stress on characteristics of the natriuretic peptides, paediatric reference values and systemic paediatric diseases with potential influence on the myocardial performance. The main focus has been NT-proBNP being the most stable NP and correlating well with BNP.

RESULTS

Most studies agree that a high NT-proBNP level indicates cardiac dysfunction in different systemic diseases such as thalassemia and cystic fibrosis or in pts after chemotherapy. In special clinical scenarios as sepsis or respiratory distress, NT-proBNP helps to narrow down the differential diagnosis or can be used for risk stratification.

CONCLUSION

NT-proBNP can serve as a screening tool in various primarily non-cardiac paediatric diseases. Together with the clinical picture, a high level suggests further assessment by a paediatric cardiologist.

Diagnostic role of plasma BNP levels in neonates with signs of congenital heart disease

BACKGROUND

Only a few studies have examined the relationship of plasma BNP levels and congenital heart disease (CHD) in neonates and these mainly concern preterm neonates with patent ductus arteriosus. We aimed to investigate the diagnostic role of plasma BNP in neonates admitted in the neonatal intensive care unit, (NICU), with signs of congenital heart disease (CHD).

METHODS

Prospective assessment of plasma BNP levels in 75 consecutive neonates with suspected CHD (heart murmur, respiratory distress, or cyanosis), admitted in the NICU of our university hospital. The final diagnosis was done with echocardiography.

RESULTS

Haemodynamically significant Left to Right shunts, (hsLtR), were found in 29 neonates, insignificant LtR shunts in 22, no heart disease in 15 and cyanotic heart disease in 9. BNP levels were significantly higher in neonates with hsLtR shunts vs. all other groups (logBNP 2.9 ± 0.5 pg/ml vs. 1.5 ± 0.4 pg/ml vs. 1.5 ± 0.3 pg/ml vs. 1.6 ± 0.2 pg/ml, p < 0.0001). Plasma BNP levels > 132.5 pg/ml had 93.1% sensitivity and 100% specificity for diagnosing hsLtR shunts (accuracy 99.6%).

CONCLUSIONS

Plasma BNP is a reliable test for diagnosing hsLtR shunts in the NICU. This will alert the neonatologist for ordering an echocardiographic examination, or if the latter is not available, for transferring the neonate to an appropriate tertiary centre with neonatal-paediatric cardiology facilities. Normal BNP levels imply the absence of a significant LtR shunt, but may not exclude cyanotic heart disease.

How useful are B-type natriuretic peptide measurements for monitoring changes in patent ductus arteriosus shunt magnitude?

OBJECTIVE

Although B-type natriuretic peptide (BNP) concentrations seem to be useful for detecting the presence of patent ductus arteriosus, there is no information about their usefulness for monitoring changes in PDA shunt magnitude.

STUDY DESIGN

We performed a retrospective analysis of paired BNP-echocardiogram measurements (obtained from infants (24 to 32 weeks gestation) with clinical suspicion of PDA).

RESULT

Individual BNP concentrations (n=146, from 88 infants) were significantly related to shunt magnitude at the time of measurement and had good discriminating power for detecting a moderate-or-large shunt (area under receiver-operator characteristic curves (ROC-AUC)=0.85). In total, 36 infants had serial BNP-echocardiogram pairs (n=91) measured during their hospitalization. Changes (either increases or decreases) in BNP concentrations over time had only fair discriminating power (ROC-AUC=0.76) for detecting increases or decreases, respectively, in shunt magnitude.

CONCLUSION

The high degree of variability in the BNP measurements made them less useful for monitoring changes in magnitude.

B-type natriuretic peptide: perioperative patterns in congenital heart disease

OBJECTIVE

B-type natriuretic peptide (BNP) has diagnostic, prognostic, and therapeutic roles in adults with heart failure. BNP levels in children undergoing surgical repair of congenital heart disease (CHD) were characterized broadly, and distinguishable subgroup patterns delineated.

DESIGN

Prospective, blinded, observational case series.

SETTING

Academic, tertiary care, free-standing pediatric hospital.

PATIENTS

Children with CHD; controls without cardiopulmonary disease. Interventions. None.

MEASUREMENTS

Preoperative cardiac medications/doses, CHD lesion types, perioperative BNP levels, intraoperative variables (lengths of surgery, bypass, cross-clamp), postoperative outcomes (lengths of ventilation, hospitalization, open chest; averages of inotropic support, central venous pressure, perfusion, urine output; death, low cardiac output syndrome (LCOS), cardiac arrest; readmission; and discharge medications).

RESULTS

Median BNP levels for 102 neonatal and non-neonatal controls were 27 and 7 pg/mL, respectively. Serial BNP measures from 105 patients undergoing CHD repair demonstrated a median postoperative peak at 12 hours. The median and interquartile postoperative 24-hour average BNP levels for neonates were 1506 (782-3784) pg/mL vs. 286 (169-578) pg/mL for non-neonates (P < 0.001). Postoperative BNP correlated with inotropic requirement, durations of open chest, ventilation, intensive care unit stay, and hospitalization (r = 0.33-0.65, all P < 0.001). Compared with biventricular CHD, Fontan palliations demonstrated lower postoperative BNP (median 150 vs. 306 pg/mL, P < 0.001), a 3-fold higher incidence of LCOS (P < 0.01), and longer length of hospitalization (median 6.0 vs. 4.5 days, P= 0.01).

CONCLUSIONS

Perioperative BNP correlates to severity of illness and lengths of therapy in the CHD population, overall. Substantial variation in BNP across time as well as within and between CHD lesions limits its practical utility as an isolated point-of-care measure. BNP commonly peaks 6-12 hours postoperatively, but the timing and magnitude of BNP elevation demonstrates notable age-dependency, peaking earlier and rising an order of magnitude higher in neonates. In spite of higher clinical acuity, non-neonatal univentricular CHD paradoxically demonstrates lower BNP levels compared with biventricular physiologies.

Fetal pulmonary vascular remodeling in a rat model induced by hypoxia and indomethacin

OBJECTIVE

This study sought to determine the effect of combined treatment of hypoxia plus indomethacin on pulmonary vascular remodeling in fetal rats.

METHODS

Hypoxia and indomethacin were used to treat pregnant rats during 19-21 days of gestation. The adventitia, media, and intima of pulmonary arteries from fetal rats were assessed. Western blots were used for determining the abundance of smooth muscle specific alpha-actin protein (α-SMA), elastin, and endothelial nitric oxide synthase (eNOS) in lung tissues. Plasma brain-type natriuretic peptide (BNP) levels, reflecting the increased right ventricular load or pulmonary arterial pressure, were detected.

RESULTS

The ratio of left ventricular free wall plus septum to right ventricular weight significantly increased in hypoxia plus indomethacin-treated group. The medial thickness percentage of pulmonary arteries of < 100 μm and ≥100 μm in diameter from hypoxia plus indomethacin-treated group was higher than that from control or single treatment group. Vascular elastin area percentage and immunostaining density of eNOS from the combined-treated group were higher than other groups. The relative abundance of α-SMA, elastin, and eNOS and plasma BNP levels in hypoxia plus indomethacin-treated group also significantly increased compared with other groups.

CONCLUSIONS

Hypoxia and indomethacin had synergistic effect on fetal pulmonary vascular remodeling. This rat model induced by combined treatments can mimic human persistent pulmonary hypertension of the newborn.

BNP concentrations and cardiovascular adaptation in preterm and fullterm newborn infants

To evaluate and compare cardiovascular adaptation of 36 preterm and 34 fullterm newborns, we analyzed BNP concentration and echocardiographic parameters at day 3 of life and at day 28 (+/-2). On day 3 BNP concentrations (pg/ml) resulted higher in PDA preterm group (n=11; 125, IQR 56.1-301) than preterm without PDA (n=25; 25.5 IQR 10.9-49; p<0.001) than fullterms (n=34; 55.1 IQR 23.6-82.7; p=0.013). No difference resulted in all groups at 28days (respectively: 12.7 IQR 4.9-23.8; 15.6 IQR 10-22; 8.9 IQR 5.6-20.6). Because of the newborns' growth, all echocardiographic parameters increased with linear relationship with body weight. On day 3 BNP concentration and echocardiographic parameters were not correlated besides LA/AO in preterms with PDA (p=0.0015). On day 28, BNP was significantly correlated with mVTI (p=0.019), M (p=0.007) and LA (p=0.005) in fullterms and only with LA (p=0.007) in preterms. In conclusion, BNP concentrations and echocardiographic measures confirm that preterm, and fullterm newborns conduct themselves in a similar manner during the transition from foetal to post-natal circulation, reaching low levels at a month of life. The presence of PDA during first days of life has no significant impact in this adaptation. LA is the echocardiographic parameter mostly related to BNP concentration in the newborns.

B-type natriuretic peptide utilization as an adjunct to management in a case of conjoined twins with pulmonary hypertension

This article reports a case of pulmonary hypertension in 37-week-gestational-age, pygopagus conjoined twins where B-type natriuretic peptide (BNP) was used as a cost-effective and important tool to aid effective management. Pulmonary hypertension in neonates is associated with high morbidity and mortality and multiplies the challenge of caring for conjoined twins. BNP is a peptide hormone secreted by cardiac ventricles that have undergone stress related to ventricular filling, volume overload, and pressure. BNP is commonly used in adults to assess heart failure, but its utility is less established in infants receiving neonatal intensive care. In this case, BNP testing was used as an adjunct to standard assessments for rapid diagnosis which was critical to expediting appropriate treatment management for these high-risk patients.

The Use of N-Terminal-Pro-BNP in Preterm Infants

The use of natriuretic peptides in the neonatal population is emerging. B-type Natriuretic Peptide (BNP) and N-terminal-Pro-BNP (NTpBNP) are used in the adult population to assess myocardial function and volume loading. Their role in prognosis following cardiac surgery has also been identified. In preterm infants NTpBNP is becoming increasingly recognised as a potential screening tool for patent ductus arteriosus (PDA), and a marker for myocardial performance. In addition, NTpBNP may provide prognostic information in preterm infants and term infants with congenital diaphragmatic hernia (CDH). In this paper, the role of NTpBNP in the preterm population will be discussed.

Does pre-eclampsia influence fetal cardiovascular function in early-onset intrauterine growth restriction?

OBJECTIVES

Increasing evidence shows that intrauterine growth restriction (IUGR) is associated with fetal cardiac dysfunction. Most studies group IUGR with and without pre-eclampsia (PE) altogether. Our objective was to evaluate whether the association with PE has any impact on cardiac function in IUGR fetuses

METHODS

Thirty-one normotensive IUGR cases and 31 IUGR cases with pre-eclampsia (PE + IUGR) below 34 weeks of gestation were included. IUGR was defined as a birth weight below the 10(th) centile together with an umbilical artery pulsatility index above 2 SD. Fetal cardiac function was assessed by measuring ductus venosus pulsatility index, modified myocardial performance index, aortic isthmus blood flow, E/A ratios and cardiac output. The presence of fetal cardiac dysfunction was also assessed by measuring cord blood B-type natriuretic peptide (BNP) levels collected at birth. Echocardiographic data were compared with those in 80 term appropriate-for-gestational age (AGA) fetuses from normotensive mothers. Cord blood BNP levels were compared with those in 40 AGA cases that delivered preterm.

RESULTS

All IUGR cases (with or without PE) showed echocardiographic and biochemical signs of cardiac dysfunction compared with AGA cases. However, no differences were observed between IUGR and PE + IUGR cases either in echocardiographic or in biochemical parameters. IUGR cases with or without PE had similar perinatal results.

CONCLUSIONS

IUGR fetuses showed echocardiographic and biochemical signs of cardiac dysfunction. Pre-eclampsia per se does not influence cardiac function in IUGR fetuses.

Amino terminal pro B-type natriuretic peptide levels are elevated in the cord blood of neonates with congenital heart defect

This prospective study investigates whether amino terminal proB-type natriuretic peptide (NT-proBNP) levels are elevated in neonates with congenital heart defect (CHD). NT-proBNP levels in the umbilical cord blood of 60 neonates with prenatally diagnosed CHD, in the cord blood of 200 control subjects, and in the plasma of the respective mothers were analyzed using an automated enzyme immunoassay. NT-proBNP concentrations in the cord blood of the CHD group were significantly elevated compared with controls [median (range): 158 pg/mL (378-3631 pg/mL) and 626 pg/mL (153-2518 pg/mL); p value <0.001]. The NT-proBNP concentrations of the newborns and their mothers did correlate neither in the CHD nor in the control group. In 54 patients with CHD, NT-proBNP levels were measured on the median 5th day of life. They showed a significant increase (median 1665 pg/mL and 19222 pg/mL; p < 0.001). NT-proBNP levels in the cord blood of neonates with CHD are significantly elevated and show a marked increase in the first week of life. Furthermore, this study confirms previously published reference intervals of NT-proBNP in the cord blood of healthy neonates as well as the finding that there is no exchange of NT-proBNP across the placenta.

Brain-type natriuretic peptide at birth reflects foetal maturation and antenatal stress

AIM

Antenatal stress, maturation and other foetal conditions affect the postnatal cardiovascular function. Atrial- (ANP) and brain-type natriuretic peptide (BNP) play important roles in regulating extracellular fluid volume and blood pressure, which may surrogate the foetal cardiovascular condition. The aim of this study was to investigate the dependence of serum ANP and BNP at birth on antenatal variables in high-risk infants.

METHODS

Plasma ANP and BNP levels in the umbilical cord blood were compared with antenatal clinical information in 280 infants.

RESULTS

High levels of ANP and BNP were associated with multiple pregnancy, antenatal magnesium sulphate and foetal distress. Caesarean section (CS) was paradoxically associated with low ANP and high BNP; low ANP was related with CS before labour whereas high BNP was related with CS after the commencement of labour. High BNP levels further correlated with younger gestational age and intrauteral growth restriction. With regard to short-term postnatal variables, high BNP levels were associated with low Apgar scores and respiratory failure whereas high ANP only correlated with the latter.

CONCLUSION

High natriuretic peptide levels were associated with prematurity at birth, uteral contraction and antenatal stress: cord blood ANP and BNP may be a useful surrogate marker for hidden antenatal stress.

Cardiac troponin T and N-terminal-pro-B type natriuretic peptide reflect myocardial function in preterm infants

BACKGROUND

Cardiovascular compromise is increasingly recognized in preterm infants. Currently, echocardiography is the best tool to assess myocardial contractility and guide management. Elevated levels of cardiac troponin T (cTnT) and N-terminal-pro-B type natriuretic peptide (NTpBNP) are associated with poor myocardial contractility and low cardiac output in adults.

OBJECTIVE

To examine the range of cTnT and NTpBNP in preterm infants, to correlate NTpBNP and cTnT with echocardiographic markers of cardiac function and to assess the influence of antenatal and postnatal factors on these biochemical markers.

STUDY DESIGN

Plasma concentrations of cTnT and NTpBNP were measured in infants <1500 g at 12 h of age. These were correlated with simultaneous echocardiographic measures of myocardial function and output. Antenatal data, infant demographics and postnatal characteristics were prospectively recorded.

RESULT

A total of 80 infant had samples taken and echocardiography performed. Their median (interquartile range) cTnT and NTpBNP values were 0.20 microg l(-1) (0.11 to 0.40) and 1273 pmol l(-1) (664 to 2798), respectively. There was a significant inverse correlation between cTnT and echocardiographic markers of myocardial function and stroke volume. NTpBNP significantly correlated with left atrial to aortic root ratio (LA:Ao). There was a weaker but significant negative correlation between NTpBNP and left ventricular (LV) function. The assays were not influenced by gestation, birth weight, gender or mode of delivery.

CONCLUSION

cTnT and NTpBNP are correlated with echocardiographic measures of cardiac performance in preterm infants. Measurement of levels in the first hours of life may provide useful information regarding myocardial function and volume loading.

Patent ductus arteriosus: an overview

Patent ductus arteriosus (PDA) is one of the most common congenital heart defects, accounting for 5%-10% of all congenital heart disease in term infants. The occurrence of PDA is inversely related to gestational age and weight, with an even greater incidence in preterm infants. The maintenance of ductal patency is essential for the normal development of the fetus. In the neonate, however, persistent patency of the ductus arteriosus (DA) is associated with significant morbidity and mortality. Normally, at birth, the DA constricts, resulting in intraluminal ischemic hypoxia, which eventually leads to closure and remodeling of the ductus. PDA in term infants is usually associated with a functional defect, whereas in preterm infants it is associated with immaturity. Normal physiologic mechanisms contributing to closure - oxygen tension and decreased prostaglandins-are altered in prematurity. Clinical signs of ductal patency include murmur, tachycardia, bounding peripheral pulses, and congestive heart failure and associated symptoms. Symptoms are not always present; therefore, diagnostic imaging is critical if a PDA is suspected on clinical grounds. Three management strategies are currently available for PDA: fluid restriction and diuretics (as clinically appropriate), medical intervention, and surgical ligation. Pharmacologic closure can be achieved via administration of intravenous indomethacin or ibuprofen lysine. While both agents have shown similar efficacy, ibuprofen lysine has demonstrated an improved safety profile, particularly in terms of renal effects, compared to indomethacin.

Patent ductus arteriosus: an overview

Patent ductus arteriosus (PDA) is one of the most common congenital heart defects, accounting for 5%-10% of all congenital heart disease in term infants. The occurrence of PDA is inversely related to gestational age and weight, with an even greater incidence in preterm infants. The maintenance of ductal patency is essential for the normal development of the fetus. In the neonate, however, persistent patency of the ductus arteriosus (DA) is associated with significant morbidity and mortality. Normally, at birth, the DA constricts, resulting in intraluminal ischemic hypoxia, which eventually leads to closure and remodeling of the ductus. PDA in term infants is usually associated with a functional defect, whereas in preterm infants it is associated with immaturity. Normal physiologic mechanisms contributing to closure - oxygen tension and decreased prostaglandins-are altered in prematurity. Clinical signs of ductal patency include murmur, tachycardia, bounding peripheral pulses, and congestive heart failure and associated symptoms. Symptoms are not always present; therefore, diagnostic imaging is critical if a PDA is suspected on clinical grounds. Three management strategies are currently available for PDA: fluid restriction and diuretics (as clinically appropriate), medical intervention, and surgical ligation. Pharmacologic closure can be achieved via administration of intravenous indomethacin or ibuprofen lysine. While both agents have shown similar efficacy, ibuprofen lysine has demonstrated an improved safety profile, particularly in terms of renal effects, compared to indomethacin.