Defining "Haemodynamic Significance" of the Patent Ductus Arteriosus: Do We Have All the Answers?

Guidelines and Recommendations for Targeted Neonatal Echocardiography and Cardiac Point-of-Care Ultrasound in the Neonatal Intensive Care Unit: An Update from the American Society of Echocardiography

Targeted neonatal echocardiography (TNE) involves the use of comprehensive echocardiography to appraise cardiovascular physiology and neonatal hemodynamics to enhance diagnostic and therapeutic precision in the neonatal intensive care unit. Since the last publication of guidelines for TNE in 2011, the field has matured through the development of formalized neonatal hemodynamics fellowships, clinical programs, and the expansion of scientific knowledge to further enhance clinical care. The most common indications for TNE include adjudication of hemodynamic significance of a patent ductus arteriosus, evaluation of acute and chronic pulmonary hypertension, evaluation of right and left ventricular systolic and/or diastolic function, and screening for pericardial effusions and/or malpositioned central catheters. Neonatal cardiac point-of-care ultrasound (cPOCUS) is a limited cardiovascular evaluation which may include line tip evaluation, identification of pericardial effusion and differentiation of hypovolemia from severe impairment in myocardial contractility in the hemodynamically unstable neonate. This document is the product of an American Society of Echocardiography task force composed of representatives from neonatology-hemodynamics, pediatric cardiology, pediatric cardiac sonography, and neonatology-cPOCUS. This document provides (1) guidance on the purpose and rationale for both TNE and cPOCUS, (2) an overview of the components of a standard TNE and cPOCUS evaluation, (3) disease and/or clinical scenario-based indications for TNE, (4) training and competency-based evaluative requirements for both TNE and cPOCUS, and (5) components of quality assurance. The writing group would like to acknowledge the contributions of Dr. Regan Giesinger who sadly passed during the final revisions phase of these guidelines. Her contributions to the field of neonatal hemodynamics were immense.

Risk stratification of hemodynamically significant patent ductus arteriosus by clinical and genetic factors

BACKGROUND

Hemodynamically significant patent ductus arteriosus (hsPDA) is associated with increased comorbidities in neonates. Early evaluation of hsPDA risk is critical to implement individualized intervention. The aim of the study was to provide a powerful reference for the early identification of high-risk hsPDA population and early treatment decisions.

METHODS

We enrolled infants who were diagnosed with PDA and performed exome sequencing. The collapsing analyses were used to find the risk gene set (RGS) of hsPDA for model construction. The credibility of RGS was proven by RNA sequencing. Multivariate logistic regression was performed to establish models combining clinical and genetic features. The models were evaluated by area under the receiver operating curve (AUC) and decision curve analysis (DCA).

RESULTS

In this retrospective cohort study of 2199 PDA patients, 549 (25.0%) infants were diagnosed with hsPDA. The model [all clinical characteristics selected by least absolute shrinkage and selection operator regression (all CCs)] based on six clinical variables was acquired within three days of life, including gestational age (GA), respiratory distress syndrome (RDS), the lowest platelet count, invasive mechanical ventilation, and positive inotropic and vasoactive drugs. It has an AUC of 0.790 [95% confidence interval (CI) = 0.749-0.832], while the simplified model (basic clinical characteristic model) including GA and RDS has an AUC of 0.753 (95% CI = 0.706-0.799). There was a certain consistency between RGS and differentially expressed genes of the ductus arteriosus in mice. The AUC of the models was improved by RGS, and the improvement was significant (all CCs vs. all CCs + RGS: 0.790 vs. 0.817, P < 0.001). DCA demonstrated that all models were clinically useful.

CONCLUSIONS

Models based on clinical factors were developed to accurately stratify the risk of hsPDA in the first three days of life. Genetic features might further improve the model performance. Video Abstract (MP4 86834 kb).

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.

Reproducibility of the EL-Khuffash PDA severity score and PDA diameter measurements in extremely preterm infants

BACKGROUND & AIM

Almost all randomised controlled trials use a Patent Ductus Arteriosus (PDA) diameter ≥ 1.5 mm as the primary criterion to ascribe haemodynamic significance to the PDA. The aim of this study was to evaluate if calculation of a PDA Severity Score (PDAsc) possessed superior intra- and inter-rater reproducibility when compared with the measurement of PDA diameter alone.

METHODS

This cross-sectional study assessed echocardiograms performed on infants <30 weeks gestation at 36 to 72 h of age between July 2020 and December 2022 to calculate the PDAsc. Intra-observer reproducibility of the PDA diameter and PDAsc were assessed by blinded repeated measurements performed by one investigator (AS) 4 weeks apart. One set of those measurements was compared with blinded measurements by another investigator (RM) to assess inter-rater reliability.

RESULTS

Echocardiograms from 150 infants with mean ± SD gestation and birthweights of 26.5 ± 1.7 weeks and 903 ± 249 g respectively were examined. The PDAsc demonstrated near perfect agreement both within raters (Cohen's Kappa 0.97, p < 0.01) and between raters (Cohen's Kappa 0.94, p < 0.01) with regards to the threshold for treatment (a cut off ≥5.0). The PDA diameter threshold only demonstrated moderate agreement within raters (Kappa 0.57, p < 0.01) and between raters (Kappa 0.54, p < 0.01). In this cohort, 31 % of infants with a low risk PDAsc (< 5.0) also had a PDA diameter >1.5 mm.

CONCLUSION

Future RCTs for PDA treatment should strongly consider abandoning the use of PDA diameter in isolation as a criterion for recruitment into clinical trials.

Platelets and ductus arteriosus closure in neonates

Platelet plug formation is critically involved in murine ductus arteriosus closure and thrombocytopenia in preterm infants seems to negatively affect spontaneous and pharmacologically induced ductal closure. Furthermore, platelet dysfunction may contribute to ductal patency, especially in extremely immature infants. Neonatal platelets likely have multifaceted roles during ductal closure, such as secretion of several signaling molecules and facilitation of specific cell-cell interactions. The only available randomized-controlled trial on platelet transfusions in preterm infants with patent ductus arteriosus demonstrated that a liberal transfusion regimen did not promote ductal closure, but was associated with an increased rate of intraventricular hemorrhage. Herein, we discuss the available mechanistic evidence on the role of platelets in ductus arteriosus closure and their potential clinical implications in preterm infants. We further briefly outline future research directions aimed at a better understanding of platelet-endothelial interactions in neonatal health and disease.

Use of Cardio-Pulmonary Ultrasound in the Neonatal Intensive Care Unit

Cardiopulmonary ultrasound (CPUS), the combination of lung ultrasound (LUS) and targeted neonatal echocardiography (TnECHO)AA, may offer a more appropriate approach to the challenging neonatal cardiovascular and respiratory disorders. This paper reviews the possible use of CPUS in the neonatal intensive care unit (NICU).

Clinical Significance of Early Pulmonary Hypertension in Preterm Infants

OBJECTIVE

To characterize different phenotypes of early pulmonary hypertension (PH) in preterm infants and their respective associations with bronchopulmonary dysplasia (BPD) and survival.

STUDY DESIGN

A prospective cohort study in a tertiary university medical center from June 2016 until March 2019. Infants with a gestational age <30 weeks and/or a birth weight <1000 g were included. Echocardiographic assessment for PH was performed at 3-10 days after birth. Subsequent development of BPD at 36 weeks postmenstrual age and mortality were assessed.

RESULTS

Early PH was identified in 55% of 104 included infants, including 21% with persistent PH of the newborn (PPHN), 61% with flow-associated PH, and 18% PH without shunt. Only PPHN was associated with placental fetal vascular malperfusion, lower gestational age, and low Apgar score. Both PPHN and flow PH were associated with the development of BPD. Early PH was associated with poorer survival, driven by PPHN.

CONCLUSIONS

Early PH is highly prevalent (55%) in preterm infants and associated with the development of BPD, independent of the phenotype of PH. Infants with PPHN had the poorest survival. Early PH presents in various phenotypes characterized by differences in etiology, pathophysiology, and associated long-term sequelae.

The role of furosemide and fluid management for a hemodynamically significant patent ductus arteriosus in premature infants

A patent ductus arteriosus (PDA) in infants born premature can present significant management challenges for neonatal providers. Quantifying a hemodynamically significant PDA (hsPDA) represents the first hurdle, however, identifying the best evidence-based approach amongst conservative, pharmacologic, and/or interventional management options has proven to be even more complicated. Within the conservative arm, furosemide to reduce pulmonary edema and improve lung function has spawned several discussions given the concerns for its upregulation of prostaglandin E₂ in the kidneys and conflicting outcomes data. There remains no consensus regarding furosemide use in hsPDAs. In this perspective article, we summarize the approach to defining a hsPDA, review the current practice of furosemide use in the management of hsPDA, and suggest an approach to fluid management and diuresis to address the question: is the routine use of furosemide in hsPDA merited in current practice?

Long-term neurodevelopmental outcomes in very low birth weight infants with and without patent ductus arteriosus: A retrospective case control observational study

BACKGROUND

Patent ductus arteriosus (PDA) has been associated with early morbidities and long-term developmental problems in very preterm infants.

AIMS

The aim of this study is to investigate the effect of patent ductus arteriosus and medical treatment on long-term developmental outcomes in very low birth weight infants.

STUDY DESIGN

This is a retrospective case control observational study.

SUBJECT

The study included preterm infants who were born before 30 weeks' gestation and birth weight less than 1,500 g and underwent neurodevelopmental testing at a corrected age of 24 months during follow-up in our centre. The results of neurodevelopmental assessment using the Bayley Scales of Infant Development II at 24 months of corrected age and other morbidities were recorded.

RESULTS

Of 820 infants screened, the 2-year data of 647 infants (78%) were analysed. The mean gestational age was 27.4 weeks (±1.7 weeks), mean birth weight was 980 g (±250 g) and 283 (44%) of the infants received pharmaceutical treatment for hemodynamically significant PDA. The prevalence of neurodevelopmental impairment was higher in infants with PDA compared to those without PDA (odds ratio [OR], 1.6; 95% CI, 1.13-2.29; chi-square, Fisher's exact test P = .009). However, when birth weight and gestational age were corrected for as covariates and other risk factors were added to the analysis, PDA alone was not an independent risk factor for neurodevelopmental problems (OR, 1.12; 95% CI, 0.824-1.549; P = .450). There was no difference between the groups who received ibuprofen or paracetamol for PDA.

CONCLUSION

Although we have not found an association between hemodynamically significant PDA and poor neurodevelopment, this potentially needs to be investigated.

Pathogenesis and prevention of intraventricular hemorrhage

Despite improvements in the mortality rates of preterm infants, rates of germinal matrix intraventricular hemorrhage (IVH) have remained static with an overall incidence of 25% in infants less than 32 weeks. The importance of the lesion relates primarily to the underlying injury to the developing brain and the associated long-term neurodevelopmental consequences. This clinical-orientated review focuses on the pathogenesis of IVH and discusses the evidence behind proposed prevention strategies.

Point-of-Care (POC) Urinary L-Type Fatty Acid-Binding Protein (u-LFABP) Use in Critically Ill, Very Preterm Neonates

Preterm neonates are born with fewer functional nephrons, rendering them vulnerable to secondary insult. These insults are associated with acute kidney injury (AKI); thus, structural damage must be detected as early as possible. Urinary L-type fatty acid-binding protein (u-LFABP) has been proposed as a highly suitable kidney injury biomarker during prematurity. We aimed to analyze the use of POC u-LFABP in critically ill, very preterm neonates. This study was conducted at the neonatal intensive care unit (NICU), Dr. Cipto Mangunkusumo General Hospital, from November to December 2020. Baseline characteristics were recorded from electronic medical records. u-LFABP examination utilized stored urine samples from a previous study and was performed using a LFABP POC test kit. The proportion of abnormal u-LFABP (83.3%) was highest at 72 hours. Neonates with older gestational age (0–48 hours; $p=0.017$ ) and higher birth weight (0–48 hours; $p=0.022$ , 72 hours; $p=0.013$ ) had normal u-LFABP levels. Neonates exposed to nephrotoxic agents showed higher proportion of abnormal u-LFABP (0–48 hours; $p=0.006$ ). Longer invasive mechanical ventilation (IMV) period was observed in neonates with abnormal u-LFABP levels at 0–48 hours (7.44 ± 7.9 vs. 1.50 ± 2.9 days; $p=0.011$ ). We found an association between complication rates and poorer disease outcome trends with abnormal u-LFABP; however, this relationship was not supported statistically. In conclusion, this study demonstrated that u-LFABP can be detected using bedside POC kit in critically ill very preterm neonates and those exposed to nephrotoxic agents may be at risk for kidney injury, confirmed by abnormal u-LFABP levels.

Percutaneous Closure of Patent Ductus Arteriosus

Percutaneous-based patent ductus arteriosus closure is technically feasible among infants less than 1.5 kg. However, marked heterogeneity in the type and nature of adverse events obscures current safety profile assessments. Although data on the risks of postdevice closure syndrome remain promising, a lack of comparative trials of surgical ductal ligation and inconsistent surveillance across published studies obscure confidence in present estimates of safety and efficacy. To minimize risk and yield the greatest benefits, clinical studies of patent ductus arteriosus treatment should consider incorporating more robust assessments to ensure that infants at greatest risk for adverse ductal consequences are included.

Early N-Terminal Pro B-Type Natriuretic Peptide (NTproBNP) Plasma Values and Associations with Patent Ductus Arteriosus Closure and Treatment-An Echocardiography Study of Extremely Preterm Infants

The aim was to investigate the association of gestational age (GA), echocardiographic markers and levels of plasma N-terminal pro-B-type natriuretic peptide (NTproBNP) with the closure rate of a haemodynamically significant patent ductus arteriosus (hsPDA). Ninety-eight Swedish extremely preterm infants, mean GA 25.7 weeks (standard deviation 1.3), born in 2012–2014, were assessed with echocardiography and for levels of NTproBNP. Thirty-three (34%) infants had spontaneous ductal closure within three weeks of age. Infants having spontaneous closure at seven days or less had significantly lower NTproBNP levels on day three, median 1810 ng/L (IQR 1760–6000 ng/L) compared with: infants closing spontaneously later, 10,900 ng/L (6120–19,200 ng/L); infants treated either with ibuprofen only, 14,600 ng/L (7740–28,100 ng/L); or surgery, 32,300 ng/L (29,100–35,000 ng/L). Infants receiving PDA surgery later had significantly higher NTproBNP values on day three than other infants. Day three NTproBNP cut-off values of 15,001–18,000 ng/L, predicted later PDA surgery, with an area under the curve in ROC analysis of 0.69 (0.54–0.83). In conclusion, the spontaneous PDA closure rate is relatively high in extremely preterm infants. Early NTproBNP levels can be used with GA in the management decisions of hsPDA.

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

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

Patent ductus arteriosus, systemic NT-proBNP concentrations and development of bronchopulmonary dysplasia in very preterm infants: retrospective data analysis from a randomized controlled trial

BACKGROUND

Patent ductus arteriosus (PDA) is a common complication in very preterm infants. It is known that there is an association between PDA and development of bronchopulmonary dysplasia (BPD) or death before the postmenstrual age (PMA) of 36 weeks, but this association remains one of the most controversial aspects of the problem. The study aimed to evaluate the relationship between PDA, serum NT-proBNP levels at 2-3 and 8-9 days of life, and BPD/death in very preterm infants.

METHODS

Data of 52 preterm infants with a gestational age < 32 weeks, chronological age < 72 h, and PDA diameter > 1.5 mm, enrolled in a randomized controlled trial, were used for the retrospective analysis. All patients underwent daily echocardiographic and two serum NT-proBNP measurements within the first 10 days after birth. Two groups of infants were formed retrospectively at PMA of 36 weeks depending on the outcome, BPD (n = 18)/death (n = 7) or survival without BPD (n = 27). Receiver operator characteristic (ROC) curve was used to evaluate the predictive performance of serum NT-proBNP levels for BPD/death occurrence.

RESULTS

The percentage of infants who received pharmacological treatment for PDA did not differ between the groups. Based on the area under the ROC curve, serum NT-proBNP levels on the 2-3 day of life (AUC = 0.71; 95% confidence interval (CI): 0.56-0.9; p = 0.014)) and on the 8-9 day of life (AUC = 0.76; 95% CI: 0.6-0.9; p = 0.002) could reliably predict BPD/death in very preterm infants who had PDA diameter > 1.5 mm in the first 72 h of life. Hemodynamically significant PDA (hsPDA) was significantly more often detected in newborns with BPD/death, however, treatment of infants with hsPDA did not reduce the incidence of BPD/death.

CONCLUSIONS

In very preterm infants with PDA > 1.5 mm at the age of 24-48 h, serum NT-proBNP concentration could reliably predict the development of BPD or death, regardless of the persistence of PDA, with the highest diagnostic value at 8-9 days.

TRIAL REGISTRATION

This study is registered in ClinicalTrials.gov - NCT03860428 on March 4, 2019.

Reintubation rates after extubation to different non-invasive ventilation modes in preterm infants

INTRODUCTION

Respiratory Distress Syndrome (RDS) is a common cause of neonatal morbidity and mortality in premature newborns. In this study, we aim to compare the reintubation rate in preterm babies with RDS who were extubated to Nasal Continuous Positive Airway Pressure (NCPAP) versus those extubated to Nasal Intermittent Positive Pressure Ventilation (NIPPV).

METHODS

This is a retrospective study conducted in the Neonatal Intensive Care Unit (NICU) of Women's Wellness and Research Center (WWRC), Doha, Qatar. The medical files (n = 220) of ventilated preterm infants with gestational age ranging between 28 weeks 0 days and 36 weeks + 6 days gestation and extubated to non-invasive respiratory support (whether NCPAP, NIPPV, or Nasal Cannula) during the period from January 2016 to December 2017 were reviewed.

RESULTS

From the study group of 220 babies, n = 97 (44%) babies were extubated to CPAP, n = 77 (35%) were extubated to NIPPV, and n = 46 (21%) babies were extubated to Nasal Cannula (NC). Out of the n = 220 babies, 18 (8.2%) were reintubated within 1 week after extubation. 14 of the 18 (77.8%) were reintubated within 48 h of extubation. Eleven babies needed reintubation after being extubated to NCPAP (11.2%) and seven were reintubated after extubation to NIPPV (9.2%), none of those who were extubated to NC required reintubation (P = 0.203). The reintubation rate was not affected by extubation to any form of non-invasive ventilation (P = 0.625). The mode of ventilation before extubation does not affect the reintubation rate (P = 0.877). The presence of PDA and NEC was strongly associated with reintubation which increased by two and four-folds respectively in those morbidities. There is an increased risk of reintubation with babies suffering from NEC and BPD and this was associated with an increased risk of hospital stay with a P-value ranging (from 0.02-0.003). Using multivariate logistic regression, NEC the NEC (OR = 5.52, 95% CI 1.26, 24.11, P = 0.023) and the vaginal delivery (OR = 0.23, 95% CI 0.07, 0.78, P = 0.018) remained significantly associated with reintubation.

CONCLUSION

Reintubation rates were less with NIPPV when compared with NCPAP, however, this difference was not statistically significant. This study highlights the need for further research studies with a larger number of neonates in different gestational ages birth weight categories. Ascertaining this information will provide valuable data for the factors that contribute to re-intubation rates and influence the decision-making and management of RDS patients in the future.

Patent ductus arteriosus shunt elimination results in a reduction in adverse outcomes: a post hoc analysis of the PDA RCT cohort

OBJECTIVE

A post hoc appraisal of the PDA RCT to assess the relationship between early patent ductus arteriosus (PDA) shunt elimination and chronic lung disease or death (CLD/Death).

STUDY DESIGN

Infants <29 weeks were divided into four groups: intervention arm in whom PDA closure was achieved (n = 17); intervention arm in whom PDA closure was not achieved (n = 13); placebo arm (n = 30); low risk infants (n = 13). The main outcome measure was CLD/Death.

RESULTS

The rates of CLD/Death were lower in the Intervention Success Group (29%) when compared to the Intervention Failure Group (85%) or the Placebo Group (60%, all p < 0.05). There was no difference in CLD/Death between the Intervention Success and Low Risk Groups (8%, p > 0.05). A persistent PDA beyond Day 8 was associated with CLD/Death (aOR 6.5 [1.7-25.5]).

CONCLUSIONS

Early shunt elimination in preterm infants with a PDA may reduce respiratory morbidity when compared to infants with prolonged shunt exposure.

Current Controversy on Platelets and Patent Ductus Arteriosus Closure in Preterm Infants

Platelets are critically involved in murine patent ductus arteriosus (PDA) closure. To date, the clinical significance of these findings in human preterm infants with PDA is still controversial. We discuss the available study data on the role of platelets for PDA closure in preterm infants: Several mostly retrospective studies have yielded conflicting results on whether thrombocytopenia contributes to failed spontaneous ductal closure. The same applies to investigations on the role of thrombocytopenia as a risk factor for unsuccessful ductus arteriosus closure by pharmacological treatment with cyclooxygenase inhibitors. Nonetheless, recent meta-analyses have concluded that thrombocytopenia constitutes an independent risk factor for both failed spontaneous and pharmacological PDA closure in preterm infants. However, the available investigations differ in regard to patient characteristics, diagnostic strategies, and treatment protocols. Several studies suggest that impaired platelet function rather than platelet number is critically involved in failure of ductus arteriosus closure in the preterm infant. A recent randomized-controlled trial on platelet transfusions in preterm infants with PDA failed to show any benefit for liberal vs. restrictive transfusion thresholds on PDA closure rates. Importantly, liberal transfusions were associated with an increased rate of intraventricular hemorrhage, and thus should be avoided. In conclusion, the available evidence suggests that thrombocytopenia and platelet dysfunction contribute to failure of spontaneous and pharmacological PDA closure in preterm infants. However, these platelet effects on PDA seem to be of only moderate clinical significance. Furthermore, platelet transfusions in thrombocytopenic preterm infants in order to facilitate PDA closure appear to cause more harm than good.

Platelet Counts and Patent Ductus Arteriosus in Preterm Infants: An Updated Systematic Review and Meta-Analysis

Background: A meta-analysis published in 2015 showed a significant association between low platelet counts in the first day(s) of life and risk of patent ductus arteriosus (PDA). The meta-analysis pooled data from 11 studies cohorts (3,479 preterm infants). Objective: To update the meta-analysis by adding new studies on the topic and including other platelet parameters different from platelet counts. Methods: PubMed/Medline and Embase databases were searched. Random-effects risk ratios (RR) and differences in means (DM) and 95% confidence intervals (CI) were calculated. Results: We included 31 studies (7,638 infants). Meta-analysis showed that the risk of developing any PDA was significantly associated with platelet counts<150 × 109/L (11 studies, RR 1.58, 95% CI 1.28 to 1.95), and <100 x 109/L (7 studies, RR 1.61, 95% CI 1.14 to 2.28), but not <50 x 109/L (4 studies, RR 1.34, 95% CI 0.77 to 2.32). Risk of developing hemodynamically significant PDA (hsPDA) was significantly associated with platelet counts<150 x 109/L (12 studies, RR 1.33, 95% CI 1.09 to 1.63), and <100 x 109/L (7 studies, RR 1.39, 95% CI 1.06 to 1.82), but not <50 x 109/L (6 studies, RR 1.24, 95% CI 0.86 to 1.79). Infants with hsPDA had significantly lower mean platelet counts (19 studies, DM 22.0 x 109, 95% CI 14.9 to 29.1) and platelet mass (11 studies, DM 214.4, 95% CI 131.2 to 297.5) and significantly higher platelet distribution width (PDW, 9 studies, DM -0.53, 95% CI -1.01 to -0.05) than infants without hsPDA. Meta-analysis could not demonstrate significant differences in mean platelet volume (MPV). Conclusion: Compared to the previous analysis, this updated meta-analysis included 21 additional studies that provide stronger evidence of the association between low platelet counts and PDA/hsPDA. Other platelet parameters such as platelet mass and PDW are also associated with hsPDA risk. However, the low number of platelets may be an epiphenomenon associated with the maturity and clinical stability of preterm infants rather than a contributing factor in the pathogenesis of PDA.

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.

Early treatment versus expectant management of hemodynamically significant patent ductus arteriosus for preterm infants

BACKGROUND

Patent ductus arteriosus (PDA) is associated with significant morbidity and mortality in preterm infants. Nonsteroidal anti-inflammatory drugs (NSAIDs) are used to prevent or treat a PDA. There are concerns regarding adverse effects of NSAIDs in preterm infants. Controversy exists on whether early targeted treatment of a hemodynamically significant (hs) PDA improves clinical outcomes.

OBJECTIVES

To assess the effectiveness and safety of early treatment strategies versus expectant management for an hs-PDA in reducing mortality and morbidity in preterm infants.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL 2019, Issue 6) in the Cochrane Library; MEDLINE via PubMed (1966 to 31 May 2019), Embase (1980 to 31 May 2019), and CINAHL (1982 to 31 May 2019). An updated search was run on 2 October 2020 in the following databases: CENTRAL via CRS Web and MEDLINE via Ovid. We searched clinical trial databases, conference proceedings, and the reference lists of retrieved articles for randomized controlled trials (RCT) and quasi-randomized trials.

SELECTION CRITERIA

We included RCTs in which early pharmacological treatment, defined as treatment initiated within the first seven days after birth, was compared to no intervention, placebo or other non-pharmacological expectant management strategies for treatment of an hs-PDA in preterm (< 37 weeks' postmenstrual age) or low birth weight (< 2500 grams) infants.

DATA COLLECTION AND ANALYSIS

We performed data collection and analyses in accordance with the methods of Cochrane Neonatal. Our primary outcome was all-cause mortality during hospital stay. We used the GRADE approach to assess the certainty of evidence for selected clinical outcomes.

MAIN RESULTS

We included 14 RCTs that enrolled 910 infants. Seven RCTs compared early treatment (defined as treatment initiated by seven days of age) versus expectant management and seven RCTs compared very early treatment (defined as treatment initiated by 72 hours of age) versus expectant management. No difference was demonstrated between early treatment versus expectant management (no treatment initiated within the first seven days after birth) for an hs-PDA for the primary outcome of 'all-cause mortality' (6 studies; 500 infants; typical RR 0.80, 95% CI 0.46 to 1.39; typical RD -0.02; 95% CI -0.07 to 0.03; moderate-certainty evidence), or other important outcomes such as surgical PDA ligation (4 studies; 432 infants; typical RR 1.08, 95% CI 0.65 to 1.80; typical RD -0.03; 95% CI -0.09 to 0.03; very low-certainty evidence), chronic lung disease (CLD) (4 studies; 339 infants; typical RR 0.90, 95% CI 0.62 to 1.29; typical RD -0.03; 95% CI -0.10 to 0.03; moderate-certainty evidence), severe intraventricular hemorrhage (IVH) (2 studies; 171 infants; typical RR 0.83,95% CI 0.32 to 2.16; typical RD -0.01; 95% CI -0.08 to 0.06; low-certainty evidence), and necrotizing enterocolitis (NEC) (5 studies; 473 infants; typical RR 2.34,95% CI 0.86 to 6.41; typical RD 0.04; 95% CI 0.01 to 0.08; low-certainty evidence). Infants receiving early treatment in the first seven days after birth were more likely to receive any PDA pharmacotherapy compared to expectant management (2 studies; 232 infants; typical RR 2.30, 95% CI 1.86 to 2.83; typical RD 0.57; 95% CI 0.48 to 0.66; low-certainty evidence). No difference was demonstrated between very early treatment versus expectant management (no treatment initiated within the first 72 hours after birth) for an hs-PDA for the primary outcome of 'all-cause mortality' (7 studies; 384 infants; typical RR 0.94, 95% CI 0.58 to 1.53; typical RD -0.03; 95% CI -0.09 to 0.04; moderate-certainty evidence) or other important outcomes such as surgical PDA ligation (5 studies; 293 infants; typical RR 0.88, 95% CI 0.36 to 2.17; typical RD -0.01; 95% CI -0.05 to 0.02; moderate-certainty evidence), CLD (7 studies; 384 infants; typical RR 0.83, 95% CI 0.63 to 1.08; typical RD -0.05; 95% CI -0.13 to 0.04; low-certainty evidence), severe IVH (4 studies, 240 infants; typical RR 0.64, 95% CI 0.21 to 1.93; typical RD -0.02; 95% CI -0.07 to 0.04; moderate-certainty evidence), NEC (5 studies; 332 infants; typical RR 1.08, 95% CI 0.53 to 2.21; typical RD 0.01; 95% CI -0.04 to 0.06; moderate-certainty evidence) and neurodevelopmental impairment (1 study; 79 infants; RR 0.27, 95% CI 0.03 to 2.31 for moderate/severe cognitive delay at 18 to 24 months; RR 0.54, 95% CI 0.05 to 5.71 for moderate/severe motor delay at 18 to 24 months; RR 0.54, 95% CI 0.10 to 2.78 for moderate/severe language delay at 18 to 24 months; low-certainty evidence). Infants receiving very early treatment in the first 72 hours after birth were more likely to receive any PDA pharmacotherapy compared to expectant management (4 studies; 156 infants; typical RR 1.64, 95% CI 1.31 to 2.05; typical RD 0.69; 95% CI 0.60 to 0.79; very low-certainty evidence). Very early treatment, however, shortened the duration of hospitalization compared to expectant management (4 studies; 260 infants; MD -5.35 days; 95% CI -9.23 to -1.47; low-certainty evidence).

AUTHORS' CONCLUSIONS

Early or very early pharmacotherapeutic treatment of an hs-PDA probably does not reduce mortality in preterm infants (moderate-certainty evidence). Early pharmacotherapeutic treatment of hs-PDA may increase NSAID exposure (low-certainty evidence) without likely reducing CLD (moderate-certainty evidence), severe IVH or NEC (low-certainty evidence). We are uncertain whether very early pharmacotherapeutic treatment of hs-PDA also increases NSAID exposure (very low-certainty evidence). Very early treatment probably does not reduce surgical PDA ligation, severe IVH or NEC (moderate-certainty evidence), and may not reduce CLD or neurodevelopmental impairment (low-certainty evidence). Additional large trials that specifically include preterm infants at the highest risk of PDA-attributable morbidity, are adequately powered for patient-important outcomes and are minimally contaminated by open-label treatment are required to explore if early targeted treatment of hs-PDA improves clinical outcomes. There are currently two trials awaiting classification and two ongoing trials exploring this question.