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

NT-proBNP cardiac value in COVID-19: a focus on the paediatric population

NT-proBNP is a peptide related to brain natriuretic peptide, a cardiac biomarker and a member of the natriuretic family of peptides. NT-proBNP has demonstrated its clinical utility in the assessment of a wide spectrum of cardiac manifestations. It is also considered a more precise diagnostic and prognostic cardiac biomarker than brain natriuretic peptide. With the appearance of the Severe Acute Respiratory Syndrome Coronavirus 2 virus and the subsequent COVID-19 pandemic, diagnosis of heart implications began to pose an increasing struggle for the physician. Echocardiography is considered a central means of evaluating cardiac disorders like heart failure, and it is considered a reliable method. However, other diagnostic methods are currently being explored, one of which involves the assessment of NT-proBNP levels. In the literature that involves the adult population, significant positive correlations were drawn between the levels of NT-proBNP and COVID-19 outcomes such as high severity and fatality. In the paediatric population, however, the literature is scarce, and most of the investigations assess NT-proBNP in the context of Multiple Inflammatory Syndrome in Children, where studies have shown that cohorts with this syndrome had elevated levels of NT-proBNP when compared to non-syndromic cohorts. Thus, more large-scale studies on existing COVID-19 data should be carried out in the paediatric population to further understand the prognostic and diagnostic roles of NT-proBNP.

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

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

Brain natriuretic peptide and N-terminal brain natriuretic peptide for the diagnosis of haemodynamically significant patent ductus arteriosus in preterm neonates

BACKGROUND

Echocardiogram is the reference standard for the diagnosis of haemodynamically significant patent ductus arteriosus (hsPDA) in preterm infants. 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, but a summary of the diagnostic accuracy has not been reviewed recently.

OBJECTIVES

Primary objective: To determine the diagnostic accuracy of the cardiac biomarkers BNP and NT-proBNP for diagnosis of haemodynamically significant patent ductus arteriosus (hsPDA) in preterm neonates. Our secondary objectives were: to compare the accuracy of BNP and NT-proBNP; and to explore possible sources of heterogeneity among studies evaluating BNP and NT-proBNP, including type of commercial assay, chronological age of the infant at testing, gestational age at birth, whether used to initiate medical or surgical treatment, test threshold, and criteria of the reference standard (type of echocardiographic parameter used for diagnosis, clinical symptoms or physical signs if data were available).

SEARCH METHODS

We searched the following databases in September 2021: MEDLINE, Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL) and Web of Science. We also searched clinical trial registries and conference abstracts. We checked references of included studies and conducted cited reference searches of included studies. We did not apply any language or date restrictions to the electronic searches or use methodological filters, so as to maximise sensitivity.

SELECTION CRITERIA

We included prospective or retrospective, cohort or cross-sectional studies, which evaluated BNP or NT-proBNP (index tests) in preterm infants (participants) with suspected hsPDA (target condition) in comparison with echocardiogram (reference standard).

DATA COLLECTION AND ANALYSIS

Two authors independently screened title/abstracts and full-texts, resolving any inclusion disagreements through discussion or with a third reviewer. We extracted data from included studies to create 2 × 2 tables. Two independent assessors performed quality assessment using the Quality Assessment of Diagnostic-Accuracy Studies-2 (QUADAS 2) tool. We excluded studies that did not report data in sufficient detail to construct 2 × 2 tables, and where this information was not available from the primary investigators. We used bivariate and hierarchical summary receiver operating characteristic (HSROC) random-effects models for meta-analysis and generated summary receiver operating characteristic space (ROC) curves. Since both BNP and NTproBNP are continuous variables, sensitivity and specificity were reported at multiple thresholds. We dealt with the threshold effect by reporting summary ROC curves without summary points.

MAIN RESULTS

We included 34 studies: 13 evaluated BNP and 21 evaluated NT-proBNP in the diagnosis of hsPDA. 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. We noted some variability in the definition of hsPDA among the included studies. For BNP, the summary curve is reported in the ROC space (13 studies, 768 infants, low-certainty evidence). The estimated specificities from the ROC curve at fixed values of sensitivities at median (83%), lower and upper quartiles (79% and 92%) were 93.6% (95% confidence interval (CI) 77.8 to 98.4), 95.5% (95% CI 83.6 to 98.9) and 81.1% (95% CI 50.6 to 94.7), respectively. Subgroup comparisons revealed differences by type of assay and better diagnostic accuracy at lower threshold cut-offs (< 250 pg/ml compared to ≥ 250 pg/ml), testing at gestational age < 30 weeks and chronological age at testing at one to three days. Data were insufficient for subgroup analysis of whether the BNP testing was indicated for medical or surgical management of PDA. For NT-proBNP, the summary ROC curve is reported in the ROC space (21 studies, 1459 infants, low-certainty evidence). The estimated specificities from the ROC curve at fixed values of sensitivities at median (92%), lower and upper quartiles (85% and 94%) were 83.6% (95% CI 73.3 to 90.5), 90.6% (95% CI 83.8 to 94.7) and 79.4% (95% CI 67.5 to 87.8), respectively. Subgroup analyses by threshold (< 6000 pg/ml and ≥ 6000 pg/ml) did not reveal any differences. Subgroup analysis by mean gestational age (< 30 weeks vs 30 weeks and above) showed better accuracy with < 30 weeks, and chronological age at testing (days one to three vs over three) showed testing at days one to three had better diagnostic accuracy. Data were insufficient for subgroup analysis of whether the NTproBNP testing was indicated for medical or surgical management of PDA. We performed meta-regression for BNP and NT-proBNP using the covariates: assay type, threshold, mean gestational age and chronological age; none of the covariates significantly affected summary sensitivity and specificity.

AUTHORS' CONCLUSIONS

Low-certainty evidence suggests that BNP and NT-proBNP have moderate accuracy in diagnosing hsPDA and may work best as a triage test to select infants for echocardiography. The studies evaluating the diagnostic accuracy of BNP and NT-proBNP for hsPDA varied considerably by assay characteristics (assay kit and threshold) and infant characteristics (gestational and chronological age); hence, generalisability between centres is not possible. We recommend that BNP or NT-proBNP assays be locally validated for specific populations and outcomes, to initiate therapy or follow response to therapy.

Can NT-proBNP Levels Be an Early Biomarker of Reduced Left Ventricular Ejection Fraction in Preterm Infants?

Background/Objective: N-terminal pro-B-type natriuretic peptide (NT-proBNP) is a cardiac natriuretic hormone that cardiomyocytes release in response to ventricular stretch. It helps with the diagnosis of heart failure in adults, but this application in preterm infants has rarely been reported. This study aimed to evaluate whether NT-proBNP could be used for the early detection of reduced cardiac ejection fraction in preterm infants and the optimal timing for NT-proBNP assessment. Design/Methods: This prospective, single-center, observational study enrolled all preterm infants with NT-proBNP measurements from October 2014 to February 2022. They underwent echocardiographic examinations within 48 h of the NT-proBNP measurements. Reduced left ventricular ejection fraction was defined as below 60%. Receiver operator characteristic (ROC) curves were generated to assess the optimal NT-proBNP cutoff point for the early prediction of reduced cardiac ejection fraction. Results: A total of 68 preterm infants were enrolled, with a total of 134 NT-proBNP measurements being available for analysis. Reduced left ventricular ejection fraction was present in seven infants (10.3%) due to various underlying diseases. The NT-proBNP cutoff level for detecting reduced left ventricular ejection fraction was 9248 pg/mL, with 71.4% sensitivity and 60.8% specificity; the area under the curve was 0.623 (95% CI: 0.487~0.760). The threshold for the optimal postnatal age for applying NT-proBNP to detect reduced left ventricular ejection fraction was >2 days of life (AUC: 0.682; 95% CI: 0.518~0.845), with 70% sensitivity and 67.1% specificity. Conclusions: Although the NT-proBNP levels declined dramatically after birth, a NT-proBNP serum level of 9248 pg/mL might be helpful for the early detection of reduced ejection fraction in preterm infants, and the optimal age for detection was after 2 days of life.

The Trend of Urinary N Terminal Probrain Natriuretic Peptide in Extremely Low Birth Weight Infants during the Neonatal Period

OBJECTIVE

N-terminal probrain natriuretic peptide (NT-proBNP) is a biomarker of interest in many cardiopulmonary diseases in extremely low birth weight (ELBW) Infants. However, there is a gap in knowledge about the trend of ELBW infant's urinary NT-proBNP during the neonatal period.

AIM

To determine the trend of urinary NT-proBNP during the first 4 weeks of life of an ELBW infant.

STUDY DESIGN

We analyzed prospectively enrolled 87 ELBW infants. Urinary NT-proBNP to creatinine ratios were measured on days 1 to 7, 14, and 28 of life. We plotted each study point's means to determine the trend of urinary NT-proBNP over the entire neonatal period. Data were analyzed using the Friedman analysis of variance for comparative analysis of study points.

RESULTS

Urinary NT-proBNP/creatinine ratios were significantly elevated on days 1 to 7 (mean 2,452, ± 1,518) than day 14 (mean 747, ± 176), and day 28 (mean 149, ± 54), p = 0.001. Overall, urinary NT-proBNP levels were highest during days 1 to 3 (mean 3,232, ± 1,255) and lowest on day 28 (mean 149, ± 54).

CONCLUSION

Urinary NT-proBNP levels are higher during the first week in ELBW infants with a downward trend during the neonatal period, the lowest values at 4 weeks postnatal age. More studies are required to determine the clinical utility of this trend during and beyond the neonatal period.

KEY POINTS

· NT-proBNP is a biomarker for monitoring cardiac disease in premature infants.. · The trend of urinary NT-proBNP is unknown in premature infants.. · A trend of urinary NT-proBNP was determined during the first 4 weeks in premature infants..

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.

Patent ductus arteriosus in preterm infants: is early transcatheter closure a paradigm shift?

The optimal management approach of the patent ductus arteriosus (PDA) in premature infants remains uncertain owing the lack of evidence for long-term benefits and the limited analyses of the complications of medical and surgical interventions to date. In recent years, devices suitable to plug the PDA of premature infants (including extremely low birthweight, <1000 g) have become available and several trials have demonstrated successful and safe transcatheter PDA closure (TCPC) in this population. Whether TCPC represents a paradigm shift in PDA management that will result in improved short- and long-term outcomes, less bronchopulmonary dysplasia, improved neurodevelopment, or better long term renal function remains to be seen. Careful rigorous study of the potential benefits of TCPC in this highly vulnerable population in the context of well-designed adequately powered trials is needed prior to widespread adoption of this approach.

Early prediction of spontaneous Patent Ductus Arteriosus (PDA) closure and PDA-associated outcomes: a prospective cohort investigation

BACKGROUND

Patent ductus arteriosus (PDA), the most commonly diagnosed cardiovascular condition in preterm infants, is associated with increased mortality and harmful long-term outcomes (chronic lung disease, neurodevelopmental delay). Although pharmacologic and/or interventional treatments to close PDA likely benefit some infants, widespread routine treatment of all preterm infants with PDA may not improve outcomes. Most PDAs close spontaneously by 44-weeks postmenstrual age; treatment is increasingly controversial, varying markedly between institutions and providers. Because treatment detriments may outweigh benefits, especially in infants destined for early, spontaneous PDA closure, the relevant unanswered clinical question is not whether to treat all preterm infants with PDA, but whom to treat (and when). Clinicians cannot currently predict in the first month which infants are at highest risk for persistent PDA, nor which combination of clinical risk factors, echocardiographic measurements, and biomarkers best predict PDA-associated harm.

METHODS

Prospective cohort of untreated infants with PDA (n=450) will be used to predict spontaneous ductal closure timing. Clinical measures, serum (brain natriuretic peptide, N-terminal pro-brain natriuretic peptide) and urine (neutrophil gelatinase-associated lipocalin, heart-type fatty acid-binding protein) biomarkers, and echocardiographic variables collected during each of first 4 postnatal weeks will be analyzed to identify those associated with long-term impairment. Myocardial deformation imaging and tissue Doppler imaging, innovative echocardiographic techniques, will facilitate quantitative evaluation of myocardial performance. Aim1 will estimate probability of spontaneous PDA closure and predict timing of ductal closure using echocardiographic, biomarker, and clinical predictors. Aim2 will specify which echocardiographic predictors and biomarkers are associated with mortality and respiratory illness severity at 36-weeks postmenstrual age. Aim3 will identify which echocardiographic predictors and biomarkers are associated with 22 to 26-month neurodevelopmental delay. Models will be validated in a separate cohort of infants (n=225) enrolled subsequent to primary study cohort.

DISCUSSION

The current study will make significant contributions to scientific knowledge and effective PDA management. Study results will reduce unnecessary and harmful overtreatment of infants with a high probability of early spontaneous PDA closure and facilitate development of outcomes-focused trials to examine effectiveness of PDA closure in "high-risk" infants most likely to receive benefit.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03782610. Registered 20 December 2018.

Cardiovascular Transition of the Extremely Premature Infant and Challenges to Maintain Hemodynamic Stability

The intricate fetal circulatory blood flow undergoes abrupt changes and restructuring at birth, allowing transition to extrauterine life and survival. In the extremely low-birth-weight newborn infant (birth weight <1000 g), these changes are affected by the immaturity of the fetal cardiovascular and pulmonary systems. The immature physiology associated with the inability to transition properly can lead to a poor prognosis and create problematic issues for the clinical management of these infants. Potentially problematic issues and complications include immature myocardium, adrenal insufficiency, patent ductus arteriosus, hypotension, and anemia. Understanding the unique transition to extrauterine life for these infants, problems that arise from immaturity and incomplete transition, and current approaches to management will help nurses and physicians caring for ELBW infants to improve the care they give and minimize mortality and morbidity in this vulnerable population. This article will review transitional physiology for term and preterm newborns, potential problems and complications, and current management approaches.

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.