Urinary NT-proBNP and ductal closure in preterm infants

Lung ultrasound score in the decision of patent ductus arteriosus closure in neonates

PURPOSE

We aimed to investigate the role of lung ultrasound (LUS) score in the closure of hemodynamically insignificant patent ductus arteriosus (PDA) and the clinical findings of the patients before and after closure.

METHODS

The study groups (107 preterm neonates under 34 gestational weeks) were classified as hemodynamically significant PDA (group 1), hemodynamically insignificant PDA with closure therapy (group 2), hemodynamically insignificant PDA without closure therapy (group 3), and no PDA group (group 4) based on the echocardiography. 6- and 10-region LUS scores were compared for each group.

RESULTS

There was a significant difference between groups 1 and 3 on first, third, and seventh days. In contrast, groups 1 and 2 had similar LUS scores on the first, third, and seventh days. There was a negative correlation between LUS scores on the first and third days and gestational age, birth weight, the first- and fifth-minute APGAR scores, and there was a positive correlation between aortic root to left atrium ratio, and PDA diameter/weight ratio.

CONCLUSION

We observed that LUS scores in patients with hemodynamically insignificant PDA treated with closure therapy were similar to in patients with hemodynamically significant PDA. Thus, LUS score can have role in PDA closure in preterm neonates. However, more comprehensive studies are needed.

Diagnostic Accuracy of Urinary N Terminal pro-B Type Natriuretic Peptides for Hemodynamically Significant-Patent Ductus Arteriosus in Preterm Infants

BACKGROUND

Echocardiography is the gold standard for the diagnosis hemodynamically significant-patent ductus arteriosus (hs-PDA). It requires trained personnel and is not readily available. Urinary biomarkers can be used as an adjunct.

OBJECTIVE

The objective of this study was to systematically review the diagnostic accuracy of urinary N terminal pro-B type natriuretic peptides (NT-proBNP) for hs-PDA in preterm neonates.

METHODS

We included studies that evaluated urinary NT-proBNP and urinary NT-proBNP/creatinine ratio (index tests) in preterm neonates with hs-PDA (participants) in comparison with echocardiogram (reference standard). Methodological quality and certainty of evidence were assessed using Quality Assessment of Diagnostic-Accuracy Studies (QUADAS-2) and Grading of Recommendations Assessment, Development and Evaluation (GRADE), respectively.

RESULTS

Low quality of evidence suggests that urinary NT-proBNP has modest sensitivity and specificity for the diagnosis of a hs-PDA, with variation in accuracy based on assay and patient characteristics.

CONCLUSION

Urinary NT-proBNP assays must be locally validated for specific patient populations and further studies to support its use must be performed.

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.

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..

Predictive Value of Blood N-Terminal Pro-Brain Natriuretic Peptide Concentrations for Early Patent Ductus Closure in Very Preterm Infants

Objectives

It has been shown that blood concentrations of NT-proBNP may be useful in identifying preterm infants at risk of hemodynamically significant patent ductus arteriosus and its complications. The aim of the study was to assess predictive value of serum NT-proBNP levels for early ductus arteriosus (DA) closure in very preterm newborns.

Methods

Fifty-two infants <32 weeks’ gestation aged <72 hours with patent ductus arteriosus (PDA) diameter >1.5 mm were involved in a randomized study. Twenty-seven (52%) of them were treated with ibuprofen or paracetamol starting within the first 3 days of life. Expectant management was applied to 25 (48%) infants. All patients underwent planned echocardiographic (daily) and two serum NT-proBNP measurements within the first 10 days after birth. Depending on the DA closure within the first 10 days of life, 2 groups of patients were formed retrospectively, with closed (n = 30) or patent (n = 22) DA by this age.

Results

In the first 10 days of life, DA closure occurred in 19 (70%) treated infants and in 11 (44%) infants managed expectantly (p > 0,05). Initial concentrations of NT-proBNP were significantly higher in infants that had patent ductus arteriosus (PDA) at 10 days of life. By the eighth day, median NT-proBNP values in both groups significantly decreased but remained considerably higher in newborns with PDA. NT-proBNP serum concentrations on the second day of life could reliably predict DA closure within the first 10 days after birth in treated babies (the AUC was significant 0.81 [95% CI: 0.58–1.03], p < 0.05) but not in infants who were managed expectantly.

Conclusions

Serum NT-proBNP concentrations on the second day of life could reliably predict early PDA closure in treated but not in expectantly managed very preterm infants.

Objective Assessment of Physiologic Alterations Associated With Hemodynamically Significant Patent Ductus Arteriosus in Extremely Premature Neonates

Delay in closure of ductus arteriosus in postnatal life may lead to serious consequences and complications in an extremely premature neonate secondary to hemodynamic alterations in regional blood flow pattern in various organs. Despite the widespread recognition amongst neonatologists to identify a hemodynamically significant patent ductus arteriosus (hsPDA) early in the postnatal course, there is lack of consensus in its definition and thus the threshold to initiate treatment. Echocardiographic assessment of PDA shunt size and volume combined with neonatologists' impression of clinical significance is most frequently used to determine the need for treatment of PDA. Common clinical signs of hsPDA utilized as surrogate for decreased tissue perfusion may lag behind early echocardiographic signs. Although echocardiogram allows direct assessment of PDA shunt and hemodynamic alterations in the heart, it is limited by dependence on pediatric cardiologist availability, interobserver variation and isolated time point assessment. Electrical cardiometry (EC) is a non-invasive continuous real time measurement of cardiac output by applying changes in thoracic electrical impedance. EC has been validated in preterm newborns by concomitant transthoracic echocardiogram assessments and may be beneficial in studying changes in cardiac output in premature newborns with hsPDA. Alterations in perfusion index derived from continuous pulse oximetry monitoring has been used to study changes in cardiac performance and tissue perfusion in infants with PDA. Near infrared spectroscopy (NIRS) has been used to objectively and continuously assess variations in renal, mesenteric, and cerebral oxygen saturation and thus perfusion changes due to diastolic vascular steal from hsPDA in preterm neonates. Doppler ultrasound studies measuring resistive indices in cerebral circulation indicate disturbance in cerebral perfusion secondary to ductal steal. With recent trends of change in practice toward less intervention in care of preterm newborn, treatment strategy needs to be targeted for select preterm population most vulnerable to adverse hemodynamic effects of PDA. Integration of these novel ways of hemodynamic and tissue perfusion assessment in routine clinical care may help mitigate the challenges in defining and targeting treatment of hsPDA thereby improving outcomes in extremely premature neonates.

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.

Early Urinary Metabolomics in Patent Ductus Arteriosus Anticipates the Fate: Preliminary Data

Introduction: In premature neonates, the persistence of hemodynamically significant ductus arteriosus (hsPDA) can be associated with short- and long-term consequences, impairing their outcome. The correct strategy of management for such condition is under debate, especially regarding contraindications and/or side effects. In recent years, metabolomics was applied to several perinatal, pediatric, and adult conditions to investigate potential biomarkers of disease, which have become useful for early diagnosis and/or therapeutic management. Aim of the Study: The main purpose of our exploratory study was to asses, through ¹H-NMR metabolomics analysis of urinary samples at birth, possible metabolic pathways differentiating, with a significant predictive power, those preterm neonates who will subsequently develop hsPDA and neonates of comparable gestational age (GA) who will undergo spontaneous ductal closure or the persistence of an irrelevant PDA (no-hsPDA). Moreover, we investigated potential prenatal or perinatal clinical factors potentially influencing the development of hsPDA. Materials and Methods: We enrolled n = 35 preterm neonates with GA between 24 and 32 weeks; urinary samples were collected within the first 12 h of life. Patients were closely monitored regarding intensive care, respiratory support, fluid balance and administered drugs; an echocardiogram was performed at 48-72 h. Results: Our results reported a significant correlation between lower GA at birth and the development of hsPDA. Moreover, neonates with GA ≤ 30w developing hsPDA were characterized by lower Apgar scores at 1' and 5', higher rates of perinatal asphyxia, higher need of delivery room resuscitation and subsequent surfactant administration. Interestingly, metabolomics analysis at birth detected a clear separation between the ¹H-NMR urinary spectra of subjects GA ≤ 30w not developing hsPDA (n = 19) and those of subjects born at GA ≤ 30w in which hsPDA was confirmed at 48-72 h of life (n = 5). Conclusions: This is the first study applying metabolomics to investigate the PDA condition. Although preliminary and conducted on a limited sample, our results reveal that metabolomics could be a promising tool in the early identification of hsPDA, potentially superior to the clinical or laboratory predictive tools explored to date and even to the clinical observations and correlations in our sample, through the detection of specific urinary metabolites.

Base excess and hematocrit predict response to indomethacin in very low birth weight infants with patent ductus arteriosus

Background

The treatment of patent ductus arteriosus (PDA) in very low birth weight (VLBW) infants remains a challenge. The ability to predict which infants will respond to indomethacin could spare some from the risks of unnecessary medications. Our objective was to determine if indicators of acid-base homeostasis could predict response to indomethacin treatment for ductal closure, and thus help guide treatment decisions.

Methods

We performed a retrospective analysis of medical records of VLBW (< 1500 g) neonates with hemodynamically significant PDA born at our institution between January 2009 and December 2012; all infants included in the study were treated with indomethacin for ductal closure within the first 2 weeks of life. We extracted data for a number of clinical variables including gestational age, birth weight, blood chemistries, surfactant use, hematocrit, and blood gas parameters. Our primary outcome measure was successful closure of PDA following the first round of indomethacin. Using variables that were significant on initial testing, we created multivariable regression models to determine the independent association of selected variables with indomethacin response.

Results

Of the 91 infants included in the study, 62 (68%) responded to the first course of indomethacin with successful ductal closure. Multivariable regression modeling revealed that both base excess and hematocrit were independently associated with indomethacin response; odds of PDA closure increased with increasing base excess (OR [odds ratio]: 1.81; 95% confidence interval [CI]: 1.36–2.60) and increasing hematocrit (OR: 1.21; 95% CI: 1.01–1.45). The optimal cutoff value for base excess was − 4.56, with a sensitivity of 96.8% (95% CI: 89–100) and specificity of 79.3% (95% CI: 60–92); optimal cutoff value for hematocrit was 40, with 69.4% sensitivity (95% CI: 56–80) and 65.5% specificity (95% CI: 46–82).

Conclusions

Base excess and hematocrit may be independent predictors of indomethacin response in VLBW infants with PDA. Low-cost and readily accessible, acid-base indicators such as base excess could help guide treatment decisions.

Electronic supplementary material

The online version of this article (10.1186/s13052-019-0706-y) contains supplementary material, which is available to authorized users.

N-terminal-probrain natriuretic peptide as a biomarker of moderate to severe bronchopulmonary dysplasia in preterm infants: A prospective observational study

OBJECTIVE

N-terminal-probrain natriuretic peptide (NT-proBNP) is a marker of hemodynamically significant patent ductus arteriosus (HsPDA) in preterm infants. In this study, we assessed whether NT-proBNP levels could predict the risk of moderate to severe bronchopulmonary dysplasia (BPD) and/or death.

METHODS

This was an observational prospective study of preterm infants with GA ≤32 weeks. Infants who died within the first 48 h or who had major congenital malformations or incomplete information were excluded. NT-proBNP was determined at 48-96 h of life and at 5-10 days of life. The predictive capacity of NT-proBNP for the combined outcome of BPD and/or death was evaluated using receiver operator characteristic (ROC) curves and multivariate regression.

RESULTS

Of the 125 eligible patients, 110 completed the analysis. Twenty-eight developed BPD (n = 15) and/or died (n = 13). Infants who developed BPD and/or died had higher NT-proBNP levels ​​at 48-96 h (26,848 ng/L, interquartile range [IQR] 7818-60,684 vs 3008 ng/L, IQR 1425-9876) and at 5-10 days (8849 ng/L, IQR 3796-19,526 vs 1427 ng/L, IQR 907-2889). The NT-proBNP levels at 5-10 days, but not at 48-96 h, were independently associated with BPD and/or death after adjustments for HsPDA and other confounders (OR = 3.36; 95%CI: 1.52-7.4, P = 0.006). For the prediction of this result, a cutoff of 3348 ng/L had a sensitivity and specificity of 82% and 83%, respectively (area under the curve [AUC] = 0.87; 95%CI: 0.79-0.95).

CONCLUSION

The NT-proBNP levels at 5-10 days of life may identify preterm infants with an HsPDA who are at high risk of BPD or death and may be useful for individualized preventive and therapeutic strategies.

Hemodynamic assessment of the patent ductus arteriosus: Beyond ultrasound

Assessment and management of a patent ductus arteriosus (PDA) in premature infants remains problematic. The more immature the infant, the more likely a PDA is to be present, due to lower spontaneous PDA closure rates. Clinicians now recognize that not all PDAs require treatment and that selection of the group of infants with a more hemodynamically relevant PDA, often manifesting as an increasing systemic-to-pulmonary shunt, is increasingly important. Ultrasound is the mainstay of diagnosis and physiological assessment of the PDA; however, there are other methodologies used to assess hemodynamic importance of the PDA. These range from assessment of clinical signs through biomarkers and finally to physiological assessment of the end-organ effect of the PDA, using methods such as cerebral Doppler or near infra-red spectroscopy. Extended assessment of a PDA's physiological effect may lead to a more individualized approach to PDA treatment.

Early NT-proBNP levels as a screening tool for the detection of hemodynamically significant patent ductus arteriosus during the first week of life in very low birth weight infants

OBJECTIVE

To assess whether early NT-ProBNP can identify the need for echocardiographic assessment of hemodynamically significant patent ductus arteriosus (HsPDA) in preterm infants.

STUDY DESIGN

Prospective observational study of infants with a gestational age ≤32 weeks. Echocardiographic assessment and NT-proBNP measurement were performed at 48-96 h. ROC curves were generated to assess optimal cutoffs to detect HsPDA and predict the need for treatment.

RESULTS

Eighty-five patients were included. HsPDA was present in 28 infants (37.6%), and 22 (25.8%) received treatment. The optimal NT-proBNP cutoff for the detection of HsPDA was 5099 pg/mL (sensitivity 94%, specificity 82%, area under the curve 0.941, P < 0.001). Only 1 child with NT-proBNP levels <5099 pg/mL was ultimately treated for PDA. NT-proBNP screening could have avoided 45 of 85 routine echocardiograms (53%).

CONCLUSION

NT-proBNP screening at 48-96 h of life may identify preterm infants at low risk for HsPDA, improving PDA management.

Urinary NT-proBNP levels and echocardiographic parameters for patent ductus arteriosus

OBJECTIVE

Patent ductus arteriosus (PDA) is common in preterm infants and is associated with significant morbidities. B type natriuretic peptide (BNP) is synthesized in the ventricles secondary to volume overload and excreted as urinary N-terminal pro-brain natriuretic peptide (NT-proBNP).

STUDY DESIGN

We report an observational prospective study of 64 preterm infants with birth weight ⩽1000 g. Echocardiographic parameters were obtained from clinical echocardiograms performed in the first week of life. Urinary NT-proBNP/creatinine ratios (pg mg^-1) were measured on the same day of the echocardiograms.

RESULTS

Infants with medium to large PDA (n=39) had significantly higher NT-proBNP/creatinine levels compared with infants with small PDA (n=10) (median (IQ range): 2333 (792-6166) vs 714 (271-1632) pg mg^-1, P=0.01) and compared with infants with no PDA (n=15) (2333 (792-6166) vs 390 (134-1085) pg mg^-1, P=0.0003). Urinary NT-proBNP/creatinine ratios were significantly lower post treatment if PDA closed (n=17), P=0.001 or if PDA became smaller after treatment (n=9), P=0.004. Urinary NT-proBNP/creatinine levels correlated with ductal diameter (P⩽0.0001), but not with LA/Ao ratio (P=0.69) or blood flow velocity through the ductus (P=0.06).

CONCLUSION

Our findings indicate that there is a positive correlation between ductal diameter and urinary NT-proBNP in preterm infants.

Paracetamol in Patent Ductus Arteriosus Treatment: Efficacious and Safe?

In preterm infants, failure or delay in spontaneous closure of Ductus Arteriosus (DA), resulting in the condition of Patent Ductus Arteriosus (PDA), represents a significant issue. A prolonged situation of PDA can be associated with several short- and long-term complications. Despite years of researches and clinical experience on PDA management, unresolved questions about the treatment and heterogeneity of clinical practices in different centers still remain, in particular regarding timing and modality of intervention. Nowadays, the most reasonable strategy seems to be reserving the treatment only to hemodynamically significant PDA. The first-line therapy is medical, and ibuprofen, related to several side effects especially in terms of nephrotoxicity, is the drug of choice. Administration of oral or intravenous paracetamol (acetaminophen) recently gained attention, appearing effective as traditional nonsteroidal anti-inflammatory drugs (NSAIDs) in PDA closure, with lower toxicity. The results of the studies analyzed in this review mostly support paracetamol efficacy in ductal closure, with inconstant low and transient elevation of liver enzymes as reported side effect. However, more studies are needed to confirm if this therapy shows a real safety profile and to evaluate its long-term outcomes, before considering paracetamol as first-choice drug in PDA treatment.

Cardiac biomarkers and haemodynamically significant patent ductus arteriosus in preterm infants

Accurately defining haemodynamically significant patent ductus arteriosus (PDA) in preterm infants who are at risk of PDA related morbidities are active areas of neonatal research. Natriuretic peptides are cardiac hormones that respond to volume and pressure loading, with elevated plasma levels found in infants with PDA. In the preterm neonatal setting, studies to date have predominantly investigated the ability of these biomarkers to discriminate between infants with and without a PDA at various postnatal ages. Their clinical utility has therefore been exclusively evaluated as a method of triaging cases of suspected hsPDA to decrease the need for echocardiograms, and to monitor treatment response. Biomarkers are yet to be robustly investigated for their ability to predict important PDA associated morbidities. In this review, we examine the most recent literature to date on the use of biomarkers in the management of PDA.

B-type and N-terminal pro-B-type natriuretic peptides are equally useful in assessing patent ductus arteriosus in very preterm infants

AIM

B-type natriuretic peptide (BNP) and N-terminal pro-BNP (NTproBNP) have been shown to correlate with the size of the patent ductus arteriosus (PDA) in preterm infants. We investigated whether BNP or NTproBNP was more closely correlated with PDA size.

METHODS

This prospective observational study included preterm infants born <32 weeks' gestation who had an echocardiogram performed within the first four days of life. Blood samples were taken simultaneously for BNP and NTproBNP measurements prior to echocardiographic examination.

RESULTS

Of the 60 infants recruited, 58 had complete data sets. The cohort's mean and standard deviation (SD) gestational age was 27(+3) (2(+2)) weeks, the mean (SD) birthweight was 1032 (315) grams, and 46 (79.3%) infants had a PDA with a mean (SD) diameter of 3.2 (0.9) mm. Median and interquartile range (IQR) BNP levels were 486.5 (219-1316) pg/mL for infants with a PDA and 190 (95.5-514.5) pg/mL for infants without a PDA. Median (IQR) NTproBNP levels were 10 858.5 (6319-42 108) pg/mL for infants with a PDA and 7488 (3363-14 227.5) pg/mL for infants without a PDA. Both BNP (R = 0.35, p = 0.0066) and NTproBNP (R = 0.31, p = 0.018) were significantly correlated with PDA size.

CONCLUSION

BNP and NTproBNP are similarly useful for assessing PDA size in preterm infants.

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.

Preterm infants who later require duct ligation show different vital signs and pH in early postnatal life

AIM

The study investigated early postnatal vital signs in very low birthweight (VLBW) infants who later developed patent ductus arteriosus (PDA). We hypothesised that the early postnatal course of vital signs and blood gas variables might differ between infants whose PDA closed spontaneously, those who responded to ibuprofen and those who later required PDA ligation.

METHODS

We analysed computerised records of VLBW infants born <28 weeks of gestational age, including vital signs, arterial pH values and echocardiographic data from the first postnatal days.

RESULTS

In total, 104 infants were included in the study. In the group of infants born <26 weeks of gestational age and requiring ibuprofen for PDA (n = 34), 12 infants ultimately required surgical ligation. Infants requiring ligation showed significantly lower oxygen saturation (p = 0.019), mean blood pressure (p = 0.034) and higher heart rate fluctuation ranges (p = 0.040) in the first five postnatal days than those who responded to ibuprofen. In multivariable logistic regression analysis, lower pH values in the first 48 h predicted the subsequent requirement for ligation independent of gestational age (p = 0.004).

CONCLUSION

Patients <26 weeks of gestational age requiring PDA ligation showed significant differences in the course of vital signs and pH during the first days of life.

Patent ductus arteriosus in preterm infants: do we have the right answers?

Patent ductus arteriosus (PDA) is a common clinical condition in preterm infants. Preterm newborns with PDA are at greater risk for several morbidities, including higher rates of bronchopulmonary dysplasia (BPD), decreased perfusion of vital organs, and mortality. Therefore, cyclooxygenase (COX) inhibitors and surgical interventions for ligation of PDA are widely used. However, these interventions were reported to be associated with side effects. In the absence of clear restricted rules for application of these interventions, different strategies are adopted by neonatologists. Three different approaches have been investigated including prophylactic treatment shortly after birth irrespective of the state of PDA, presymptomatic treatment using echocardiography at variable postnatal ages to select infants for treatment prior to the duct becoming clinically significant, and symptomatic treatment once PDA becomes clinically apparent or hemodynamically significant. Future appropriately designed randomized controlled trials (RCTs) to refine selection of patients for medical and surgical treatments should be conducted. Waiting for new evidence, it seems wise to employ available clinical and echocardiographic parameters of a hemodynamically significant (HS) PDA to select patients who are candidates for medical treatment. Surgical ligation of PDA could be used as a back-up tool for those patients who failed medical treatment and continued to have hemodynamic compromise.