Effect of Nonintervention vs Oral Ibuprofen in Patent Ductus Arteriosus in Preterm Infants: A Randomized Clinical Trial

At a crossroads for early medical treatment of persistent patent ductus arteriosus in preterm infants

Administration of early medical therapy for the patent ductus arteriosus has ebbed and flowed through the years, with a multitude of studies failing to demonstrate a reduction in morbidity or mortality from ductal closure in the preterm population. Concerningly, an increasing number of studies have demonstrated an increase in morbidity, such as bronchopulmonary dysplasia and mortality with the use of early medical therapy to close the ductus. Considering information regarding potential risk without clear benefit in an overall cohort of preterm patients with a patent ductus, use of early medical therapy is increasingly challenging to justify and necessitates studies that will aid in identifying a patient population that would benefit from ductal closure and timing of therapy.

Genetic Foundation of Prostaglandin Metabolism Influences Patent Ductus Arteriosus Closure in Extremely Low Birth Weight Infants

OBJECTIVE

 Prostaglandins (PGs) play a major role in maintaining patency of the ductal arteriosus (DA). Pulmonary 15-hydroxyprostaglandin dehydrogenase (PGDH), which is ecoded by the hydroxyprostaglandin dehydrogenase (HPGD) gene, is the primary enzyme responsible for PG breakdown. Animal studies have shown HPGD-knockout mice have significantly higher prostaglandin E2 levels and no ductal remodeling. Functional variants of the HPGD gene that alter PG breakdown have not been studied in preterm infants with patent ductus arteriosus (PDA).

STUDY DESIGN

 This was an observational cohort study including extreme low birth weight (ELBW) infants classified as having spontaneous, medical, or procedural (transcatheter or surgical ligation) closure of their DA. Urine prostaglandin E metabolite (PGEM) levels were measured in ELBW infants following ibuprofen treatment using competitive ELISA. HPGD genetic variants rs8752, rs2612656, and rs9312555 were analyzed. Kruskal-Wallis, Fisher's exact, chi square, logistic regression, and Wilcoxon signed-rank tests were used; p < 0.05 was considered significant.

RESULTS

 Infants in the procedural closure group had a younger gestational age (GA). The incidence of spontaneous closure or medical closure was higher compared to procedural closure in the presence of any minor allele of rs8752 (67 and 27%, respectively; p = 0.01), when adjusted for GA and gender. Haplotype analysis of three variants of HPGD revealed differences when comparing the spontaneous and medical closure group to the procedural group (p < 0.05). Urinary PGEM levels dropped significantly in those ELBW infants who responded to ibuprofen (p = 0.003) in contrast to those who did not respond (p = 0.5).

CONCLUSION

 There was a different genotype distribution for the rs8752 genetic variant of the HPGD gene-as it relates to the mode of treatment for ELBW infants with PDA. We speculate that medical management in the presence of this variant facilitated additional PG breakdown, significantly abrogating the need for procedural closure. Additionally, differences in genotype and haplotype distributions implicate a specific HPGD genetic foundation for DA closure in ELBW infants.

KEY POINTS

· PGs and their metabolism play a major role in PDA patency or closure.. · Genetic variants of the HPGD gene influence mode of treatment of PDA in ELBW infants.. · ELBW infants with PDA that responded to medical closure had significantly decreased urine PGEM levels..

Patent ductus arteriosus management in very-low-birth-weight prematurity: a place for an early operation?

OBJECTIVES

The goal was to evaluate neonatal outcomes based on treatment strategies and time points for haemodynamically significant patent ductus arteriosus (hsPDA) in very-low-birth-weight preterm infants, with a particular focus on surgical closure.

METHODS

This retrospective study included very-low-birth-weight infants born between 2014 and 2021 who received active treatment for hsPDA. Neonatal outcomes were compared between (i) primary surgical closure versus primary ibuprofen; (ii) early (<14th post-natal day) versus late primary surgical closure (≥14th post-natal day); and (iii) primary versus secondary surgical closure after ibuprofen failure. Further analysis using 1:1 propensity score matching was performed. Logistic regression was conducted to analyse the risk factors for post-ligation cardiac syndrome (PLCS) and/or acute kidney injury (AKI).

RESULTS

A total of 145 infants with hsPDA underwent active treatment for closure. The in-hospital death rate and the incidence of severe bronchopulmonary dysplasia (BPD) were similar between the primary surgical closure group and the primary ibuprofen group in a 1:1 matched analysis. Severe BPD was significantly higher in the late surgical closure group than in the early primary surgical closure group with 1:1 propensity score matching (72.7% vs 40.9%, P=0.033). The secondary surgical closure group showed the mildest clinical condition; however, the probability of PLCS/AKI was highest (38.6%) compared to the early (15.2%) or the late primary surgical group (28.1%, P<0.001), especially in extremely premature infants (gestational age < 28 weeks).

CONCLUSIONS

Surgical patent ductus arteriosus closure is not inferior to pharmacologic treatment. Considering the harmful effect of a prolonged patent ductus arteriosus shunt exposure, a timely decision and timely efforts should be made to minimize the risk of severe BPD and PLCS/AKI after surgical closure.

A predictive model for patent ductus arteriosus seven days postpartum in preterm infants: an ultrasound-based assessment of ductus arteriosus intimal thickness within 24 h after birth

Objectives

To develop a predictive model for patent ductus arteriosus (PDA) in preterm infants at seven days postpartum. The model employs ultrasound measurements of the ductus arteriosus (DA) intimal thickness (IT) obtained within 24 h after birth.

Methods

One hundred and five preterm infants with gestational ages ranging from 27.0 to 36.7 weeks admitted within 24 h following birth were prospectively enrolled. Echocardiographic assessments were performed to measure DA IT within 24 h after birth, and DA status was evaluated through echocardiography on the seventh day postpartum. Potential predictors were considered, including traditional clinical risk factors, M-mode ultrasound parameters, lumen diameter of the DA (LD), and DA flow metrics. A final prediction model was formulated through bidirectional stepwise regression analysis and subsequently subjected to internal validation. The model's discriminative ability, calibration, and clinical applicability were also assessed.

Results

The final predictive model included birth weight, application of mechanical ventilation, left ventricular end-diastolic diameter (LVEDd), LD, and the logarithm of IT (logIT). The receiver operating characteristic (ROC) curve for the model, predicated on logIT, exhibited excellent discriminative power with an area under the curve (AUC) of 0.985 (95% CI: 0.966-1.000), sensitivity of 1.000, and specificity of 0.909. Moreover, the model demonstrated robust calibration and goodness-of-fit (χ2 value = 0.560, p > 0.05), as well as strong reproducibility (accuracy: 0.935, Kappa: 0.773), as evidenced by 10-fold cross-validation. A decision curve analysis confirmed the model's broad clinical utility.

Conclusions

Our study successfully establishes a predictive model for PDA in preterm infants at seven days postpartum, leveraging the measurement of DA IT. This model enables identifying, within the first 24 h of life, infants who are likely to benefit from timely DA closure, thereby informing treatment decisions.

Secular Trends in Patent Ductus Arteriosus Management in Infants Born Preterm in the National Institute of Child Health and Human Development Neonatal Research Network

We evaluated changes in patent ductus arteriosus (PDA) diagnosis and treatment from 2012 through 2021 in a network of US academic hospitals. PDA treatment decreased among infants born at 26-28 weeks but not among infants born at 22-25 weeks. Rates of indomethacin use and PDA ligation decreased while acetaminophen use and transcatheter PDA closure increased.

Treatment of patent ductus arteriosus and short-term outcomes among extremely preterm infants: a multicentre cohort study

Background

The optimal treatment strategy for patent ductus arteriosus (PDA) in extremely preterm infants is currently highly controversial. This study aimed to evaluate the association between PDA treatment and short-term outcomes among extremely preterm infants.

Methods

This cohort study included all extremely preterm infants (≤27 and 6/7 weeks) who were admitted to hospitals participating in the Chinese Neonatal Network from January 2019 to December 2021, and were diagnosed to have PDA by echocardiogram. PDA treatment was defined as medical treatment and/or surgical ligation of PDA during hospitalization. Short-term outcomes included death, bronchopulmonary dysplasia (BPD), death/BPD, retinopathy of prematurity, necrotizing enterocolitis, and severe brain injury. Multivariate logistic regression was used to evaluate the association between PDA treatment and outcomes. Subgroup analysis were performed among infants with different respiratory support on 3 and 7 days of life.

Findings

A total of 2494 extremely preterm infants with the diagnosis of PDA were enrolled, of which 1299 (52.1%) received PDA treatment. PDA treatment was significantly associated with lower risk of death (adjusted odds ratio, 0.48; 95% confidence interval, 0.38-0.60). The decreased risk of death was accompanied by increased risk of BPD and death/BPD. In subgroup analysis according to respiratory support, PDA treatment was associated with lower risk of death among infants who required invasive ventilation. However, the beneficial effect on death was not significant among infants who did not require invasive ventilation.

Interpretation

PDA treatment was associated with reduced mortality in extremely preterm infants, but this beneficial effect was mainly present among infants who required invasive ventilation.

Funding

This study was funded by the Shanghai Science and Technology Commission's Scientific and Technological Innovation Action Plan (21Y21900800) and the Canadian Institutes of Health Research (CTP87518).

Expectant management of patent ductus arteriosus for preterm infants: A meta-analysis of randomized controlled trials

We conducted this meta-analysis to compare expectant management of patent ductus arteriosus (PDA) with active treatment for PDA closure in preterm infants. Data from 7 randomized controlled trials (RCTs) showed that all-cause mortality and other clinical adverse outcomes did not differ between expectant management of PDA and active treatment. Future large-scale and double-blinded RCTs with a consistent definition for hemodynamically significant PDA, and focusing on clearly delineated high-risk subgroups or later selective treatment are needed to further evaluate the role of expectant management.

The past, current, and future of neonatal intensive care units with artificial intelligence: a systematic review

Machine learning and deep learning are two subsets of artificial intelligence that involve teaching computers to learn and make decisions from any sort of data. Most recent developments in artificial intelligence are coming from deep learning, which has proven revolutionary in almost all fields, from computer vision to health sciences. The effects of deep learning in medicine have changed the conventional ways of clinical application significantly. Although some sub-fields of medicine, such as pediatrics, have been relatively slow in receiving the critical benefits of deep learning, related research in pediatrics has started to accumulate to a significant level, too. Hence, in this paper, we review recently developed machine learning and deep learning-based solutions for neonatology applications. We systematically evaluate the roles of both classical machine learning and deep learning in neonatology applications, define the methodologies, including algorithmic developments, and describe the remaining challenges in the assessment of neonatal diseases by using PRISMA 2020 guidelines. To date, the primary areas of focus in neonatology regarding AI applications have included survival analysis, neuroimaging, analysis of vital parameters and biosignals, and retinopathy of prematurity diagnosis. We have categorically summarized 106 research articles from 1996 to 2022 and discussed their pros and cons, respectively. In this systematic review, we aimed to further enhance the comprehensiveness of the study. We also discuss possible directions for new AI models and the future of neonatology with the rising power of AI, suggesting roadmaps for the integration of AI into neonatal intensive care units.

Lung ultrasound score predicts patent ductus arteriosus ligation among neonates ≤25 weeks

BACKGROUND

This prospective study aimed to investigate whether lung ultrasound score (LUSs) can predict the patent ductus arteriosus (PDA) ligation.

METHODS

Preterm infants ≤25 weeks of gestational age (GA) were enrolled. A lung ultrasound was performed on the 14th day of life. Each lung zone was given a score between 0 and 4. A receiver-operating characteristic (ROC) curve was constructed to evaluate the ability of the LUSs for predicting ligation.

RESULTS

A total of 81 infants were eligible with a median GA and birth weight (BW) of 25 weeks (24.1-25.2) and 710 g (645-770), respectively. The median time from birth to ligation was 35 days (32-51). Those who underwent ligation had a longer time of mechanical ventilation (34 [26-39] vs. 19 [12-30], p < 0.001), shorter time of noninvasive respiratory support (39 [32-51] vs. 50 [41.5-57], p < 0.01), higher incidence of the bronchopulmonary dysplasia (BPD) (p < 0.01), and severe BPD (p < 0.001). The LUSs had an area under the ROC of 0.96 (95% confidence interval: 0.93-0.99) for the prediction of ligation. A LUSs cutoff of 36 has a sensitivity and specificity of 96% and 86% and positive and negative predictive values of 82% and 98%, respectively.

CONCLUSIONS

LUSs at an early stage of life can predict PDA ligation in extremely preterm infants. It would be helpful to reduce morbidity by reducing the duration and magnitude of respiratory support.

Increasing the dose of ibuprofen with postnatal age to close a hemodynamically significant patent ductus arteriosus in very preterm infants

Patent ductus arteriosus (PDA) is associated with neonatal morbidities in high-risk preterm infants. Early neonatal treatment by ibuprofen induces the ductus arteriosus (DA) closure in approximatively 60% of infants. Dose escalation of ibuprofen according to postnatal age has been suggested for improving the DA closure rate. The aim of this study was to assess the efficacy and tolerance of an increasing dose regimen of ibuprofen. This single-center retrospective cohort study involved infants hospitalized from 2014 to 2019 in our neonatal unit. Selection criteria were gestational age < 30 weeks, birth weight < 1000 g, and treatment by ibuprofen. Three dose levels were used and consisted of a daily intravenous injection of ibuprofen-tris-hydroxymethyl-aminomethane (ibuprofen-THAM) for three consecutive days: (i) 10 -5 -5 mg/kg before the 70th h of life (H70) (dose level 1), (ii) 14 -7 -7 mg/kg between H70 and H108 (dose level 2), (iii) 18 -9 -9 mg/kg after H108 (dose level 3). The ibuprofen-induced DA closure was compared between ibuprofen schedules, and the Cox proportional-hazard regression was performed to identify factors associated with the ibuprofen efficacy. Tolerance was assessed through renal function, acidosis, and platelet count. One hundred forty-three infants met the inclusion criteria. The ibuprofen-induced DA closure was observed in 67 infants (46.8%). One course of ibuprofen at dose level 1 was more efficient in closing the DA than other schedules (dose level 1, one course (n = 70): 71%, dose level 2 or 3, one course (n = 20): 45%, two-course schedules (n = 53): 15%, p < 0.0001). Independent factors associated with ibuprofen-induced DA closure were a complete antenatal schedule of steroids (p = 0.001), a lower CRIB II score (p = 0.009), and a lower and earlier exposure to ibuprofen (p < 0.0001 and p = 0.002). No severe side effects were observed. Neonatal mortality and morbidities were similar regardless of the infant's response to ibuprofen.  Conclusion: Increasing ibuprofen doses with postnatal age failed to reach an efficacy similar to earlier treatment. Although the infant response to ibuprofen was likely to depend on multiple factors, the optimal use of ibuprofen included its early initiation. What is Known: • Ibuprofen is the current first-line treatment for patent ductus arteriosus during the early neonatal period in very preterm infants. • However, the ibuprofen efficacy rapidly declined with postnatal age during the first week of life. A dose escalation of ibuprofen according to postnatal age has been suggested to improve the ibuprofen-induced ductus arteriosus closure. What is New: • The rapid drop of ibuprofen's ability to close hemodynamically significant patent ductus arteriosus persisted beyond the postnatal day 2 despite the dose adjustment arguing for an early initiation to optimize its efficacy. • The early selection of patients who will suffer from patent ductus arteriosus-related morbidities and who will positively respond to ibuprofen is an issue that could determine the future place of ibuprofen in the patent ductus arteriosus management.

Expectant Management or Early Ibuprofen for Patent Ductus Arteriosus

BACKGROUND

Cyclooxygenase inhibitors are commonly used in infants with patent ductus arteriosus (PDA), but the benefit of these drugs is uncertain.

METHODS

In this multicenter, noninferiority trial, we randomly assigned infants with echocardiographically confirmed PDA (diameter, >1.5 mm, with left-to-right shunting) who were extremely preterm (<28 weeks' gestational age) to receive either expectant management or early ibuprofen treatment. The composite primary outcome included necrotizing enterocolitis (Bell's stage IIa or higher), moderate to severe bronchopulmonary dysplasia, or death at 36 weeks' postmenstrual age. The noninferiority of expectant management as compared with early ibuprofen treatment was defined as an absolute risk difference with an upper boundary of the one-sided 95% confidence interval of less than 10 percentage points.

RESULTS

A total of 273 infants underwent randomization. The median gestational age was 26 weeks, and the median birth weight was 845 g. A primary-outcome event occurred in 63 of 136 infants (46.3%) in the expectant-management group and in 87 of 137 (63.5%) in the early-ibuprofen group (absolute risk difference, -17.2 percentage points; upper boundary of the one-sided 95% confidence interval [CI], -7.4; P<0.001 for noninferiority). Necrotizing enterocolitis occurred in 24 of 136 infants (17.6%) in the expectant-management group and in 21 of 137 (15.3%) in the early-ibuprofen group (absolute risk difference, 2.3 percentage points; two-sided 95% CI, -6.5 to 11.1); bronchopulmonary dysplasia occurred in 39 of 117 infants (33.3%) and in 57 of 112 (50.9%), respectively (absolute risk difference, -17.6 percentage points; two-sided 95% CI, -30.2 to -5.0). Death occurred in 19 of 136 infants (14.0%) and in 25 of 137 (18.2%), respectively (absolute risk difference, -4.3 percentage points; two-sided 95% CI, -13.0 to 4.4). Rates of other adverse outcomes were similar in the two groups.

CONCLUSIONS

Expectant management for PDA in extremely premature infants was noninferior to early ibuprofen treatment with respect to necrotizing enterocolitis, bronchopulmonary dysplasia, or death at 36 weeks' postmenstrual age. (Funded by the Netherlands Organization for Health Research and Development and the Belgian Health Care Knowledge Center; BeNeDuctus ClinicalTrials.gov number, NCT02884219; EudraCT number, 2017-001376-28.).

Combination pharmacotherapy for patent ductus arteriosus: Rationale and evidence

While cyclooxygenase inhibitors have been the most common medications used to facilitate earlier closure of patent ductus arteriosus in preterm infants, adverse effects and low efficacy in extremely low gestational age neonates (ELGANs) have highlighted a need for alternative options. Combination therapy with acetaminophen and ibuprofen is a novel strategy for PDA treatment in ELGANs, as it may facilitate higher ductal closure rates via additive action on two separate pathways inhibiting prostaglandin production. Initial small observational studies and pilot randomized clinical trials indicate potentially higher efficacy of the combination regime to induce ductal closure in comparison to treatment with ibuprofen alone. In this review, we examine the potential clinical impact of treatment failure in ELGANs with significant PDA, highlight the biological rationale in support of studying combination therapy, and review the randomized and non-randomized studies to date. With the rising number of ELGANs receiving neonatal intensive care, who are vulnerable to PDA-related morbidities, there is an urgent need for adequately powered clinical trials to systematically investigate the efficacy and safety of combination therapy for PDA treatment.

Conservative Management of Patent Ductus Arteriosus Is Feasible in the Peri-Viable Infants at 22-25 Gestational Weeks

The purpose of this study was to determine the natural course of hemodynamically significant (HS) patent ductus arteriosus (PDA) with conservative management and whether the presence or prolonged duration of HS PDA affected mortality/morbidities in infants at 22-25 weeks estimated gestational age (EGA). We retrospectively reviewed the medical records of 77 infants born at 22-25 weeks EGA, stratified into 22-23 weeks (n = 21) and 24-25 weeks EGA (n = 56). HS PDA was present in 77%, 76%, and 77%, and open ductus at discharge was 12%, 13%, and 12% in the total and at 22-23 and 24-25 weeks EGA infants, respectively. For backup rescue treatment, 7% and 5% of the infants received oral ibuprofen and device closure, respectively. A mortality rate of 9% was found in the HS PDA (+) infants, significantly lower than the 28% in HS PDA (-) infants. There are no significant differences in morbidities. In multivariate analyses, the presence and/or prolonged duration of HS PDA was not associated with increased mortality or morbidity. Spontaneous closure of HS PDA was achieved through conservative management in the peri-viable infants at 22-25 weeks EGA.

Comparison of Various Pharmacologic Agents in the Management of Hemodynamically Significant Patent Ductus Arteriosus in Preterm: A Network Meta-Analysis and Risk-Benefit Analysis

INTRODUCTION

Various pharmacological treatments are available for preterm infants with patent ductus arteriosus (PDA), but their risks and benefits are controversial. This study aimed to identify the best treatment for PDA using network meta-analysis (NMA) and risk-benefit assessment (RBA).

METHODS

Relevant randomized controlled trials (RCTs) were identified from MEDLINE, Scopus, and the Cochrane Library. RCTs were eligible if they were studied for preterm or low birth weight infants with presymptomatic PDA and hemodynamically significant PDA (hsPDA). The outcomes were PDA closure for a benefit and the composite risk outcome of adverse effects (AEs) for risk. An NMA was used to estimate the treatment effects of benefit and risk. The RBA helped to incorporate the risk and benefits of multiple treatments. Then, an incremental risk-benefit ratio was calculated by dividing the incremental risk by benefit using data from NMA, and they were jointly simulated using Monte Carlo methods. Finally, net clinical benefit (NCB) probability curves were constructed at varying acceptability thresholds.

RESULTS

Seventy RCTs with hsPDA were eligible considering 13 different interventions, but data on presymptomatic PDA were not enough for pooling. The clustered ranking plot from NMA indicated that 3 interventions (i.e., high-dose oral ibuprofen, standard-dose oral acetaminophen, and standard-dose oral ibuprofen) yielded high PDA closure and low AE. These three treatments and additional commonly used indomethacin were considered in the RBA. Given an acceptable threshold of 25% or having one AE out of four PDA closures, high-dose oral ibuprofen had a 36% chance of having the highest NCB, followed by standard-dose oral acetaminophen (27%), and oral ibuprofen (23.7%). Subgroup analysis indicated that the chances of having the highest NCB of GA ≥28 weeks were similar to that of all available studies. The best for GA <28 weeks, no data for high-dose oral ibuprofen, was standard-dose oral acetaminophen, followed by standard-dose oral ibuprofen.

CONCLUSIONS

Trade-off RBA indicated that high-dose oral ibuprofen might be the best treatment for preterm, GA ≥28 weeks, with hsPDA followed by the standard-dose oral acetaminophen and ibuprofen. Preferably, optimal high doses, postnatal age to start treatment, and long-term outcomes are needed to study in the future.

Echocardiographic assessment of intimal thickness growth of patent ductus arteriosus in neonates and analysis of influencing factors

The spontaneous closure rate of patent ductus arteriosus (PDA) is high, and the necessity of early intervention is debated. Quantitative echocardiographic assessment of the intima in PDA has not been reported. This study evaluated intimal thickness growth in neonatal cases of PDA via echocardiography and investigated its correlation with clinical factors. Seventy-three neonates were enrolled, and echocardiography was performed three times: within 24 h post-birth (first echo), 48 h after the first echo (second echo), and before discharge (third echo). According to PDA outcome, the neonates were divided into the PDA-open group (n = 18 cases), PDA-closure at second echo group (n = 32 cases), and non-PDA at first echo group (n = 23 cases). We measured the intimal thickness (IT1 and IT2 at first and second echo, respectively), lumen diameter of ductus arteriosus (D1 and D2 at first and second echo, respectively), IT1/D1 ratio, and intimal thickness growth rate (V). Correlations between echocardiographic indicators, perinatal factors, and clinical treatment were analyzed. On first echo, the PDA-open group showed a significantly lower IT1/D1 than the combined PDA-closure group (P < 0.05). On second echo, the PDA-open group showed a significantly lower IT2 and V than the PDA-closure group as well as a significantly higher D2 (P < 0.05). Smaller gestational age correlated with a larger D2 but smaller IT2 and V (P < 0.05) and a higher level of respiratory support within 72 h post-birth correlated with a larger D2 and smaller IT 2 (P < 0.05). Increasing oxygen demand within 72 h of birth correlated with a larger D1 and D2 (P < 0.05). Echocardiographic assessment of intimal thickness growth in PDA may provide an approach for predicting spontaneous PDA closure, thereby guiding decision-making regarding early intervention.

Protecting the brain of the micropreemie

Advances in perinatal care have seen substantial improvements in survival without disability for extremely preterm infants. Protecting the developing brain and reducing neurodevelopmental sequelae of extremely preterm birth are strategic priorities for both research and clinical care. A number of evidence-based interventions exist for neuroprotection in micropreemies, inclusive of prevention of preterm birth and multiple births with implantation of only one embryo during in vitro fertilisation, as well as antenatal care to optimize fetal wellbeing, strategies for supporting neonatal transition, and neuroprotective developmental care. Avoidance of complications that trigger ischemia and inflammation is vital for minimizing brain dysmaturation and injury, particularly of the white matter. Neurodevelopmental surveillance, early diagnosis of cerebral palsy and early intervention are essential for optimizing long-term outcomes and quality of life. Research priorities include further evaluation of putative neuroprotective agents, and investigation of common neonatal interventions in trials adequately powered to assess neurodevelopmental outcome.

2021 Update on Pediatric Overuse

This update on pediatric medical overuse identifies and provides concise summaries of 10 impactful articles related to pediatric medical overuse from the years 2019 to 2020.

Patent ductus arteriosus, tracheal ventilation, and the risk of bronchopulmonary dysplasia

BACKGROUND

An increased risk for bronchopulmonary dysplasia (BPD) exists when moderate-to-large patent ductus arteriosus shunts (hsPDA) persist beyond 14 days.

GOAL

To examine the interaction between prolonged exposures to tracheal ventilation (≥10 days) and hsPDA on the incidence of BPD in infants <28 weeks gestation.

STUDY DESIGN

Predefined definitions of prolonged ventilation (≥10 days), hsPDA (≥14 days), and BPD (room air challenge test at 36 weeks) were used to analyze deidentified data from the multicenter TRIOCAPI RCT in a secondary analysis of the trial.

RESULTS

Among 307 infants who survived >14 days, 41 died before 36 weeks. Among survivors, 93/266 had BPD. The association between BPD and hsPDA depended on the length of intubation. In multivariable analyses, prolonged hsPDA shunts were associated with increased BPD (odds ratio (OR) (95% confidence interval (CI)) = 3.00 (1.58-5.71)) when infants required intubation for ≥10 days. In contrast, there was no significant association between hsPDA exposure and BPD when infants were intubated <10 days (OR (95% CI) = 1.49 (0.98-2.26)). A similar relationship between prolonged hsPDA and length of intubation was found for BPD/death (n = 307): infants intubated ≥10 days: OR (95% CI) = 2.41 (1.47-3.95)); infants intubated <10 days: OR (95% CI) = 1.37 (0.86-2.19)).

CONCLUSIONS

Moderate-to-large PDAs were associated with increased risks of BPD and BPD/death-but only when infants required intubation ≥10 days.

IMPACT

Infants with a moderate-to-large hsPDA that persist beyond 14 days are only at risk for developing BPD if they also receive prolonged tracheal ventilation for ≥10 days. Infants who receive less ventilatory support (intubation for <10 days) have the same incidence of BPD whether the ductus closes shortly after birth or whether it persists as a moderate-to-large shunt for several weeks. Early PDA closure may be unnecessary in infants who require short durations of intubation since the PDA does not seem to alter the incidence of BPD in infants who require intubation for <10 days.

Survey highlighting the lack of consensus on diagnosis and treatment of patent ductus arteriosus in prematurity

To gain insight in the availability of guidelines, diagnostic criteria, and treatment strategies and whether clinical equipoise regarding optimal treatment for patent ductus arteriosus (PDA) in prematurity is present. We hypothesized that (co-)authors of PDA-related papers were more likely to screen for a PDA and would treat earlier and more aggressively. An international internet-based survey between September 2019 and March 2020 in which we collected (1) baseline characteristics; (2) availability of guidelines; (3) screening strategy for PDA; (4) diagnostic criteria for hemodynamic significance; (5) treatment strategy; and (6) metrics of treatment efficacy. Finally, ten clinical equipoise statements were posed on a Likert scale. In total, 144 surveys were sent, of which 71/144 (49%) surveys could be analyzed with 56/71 (79%) fully completed surveys. The respondents, mainly neonatologists in a level III neonatal intensive care unit, of whom 36/71 (51%) had (co-)authored a publication on the PDA, highlighted a lack of national guidelines, heterogeneous approach to screening strategies, and marked variability in diagnostic criteria to assess hemodynamic significance, treatment strategies and effect measurement. No major significant differences were observed between respondents who did or did not (co-)author a publication on the PDA. Respondents who screened for PDA scored significantly higher on the need for screening, early and aggressive treatment. Remarkably, the scores of all statements regarding clinical equipoise varied widely.   Conclusions: Our survey highlights the lack of guidelines and enormous heterogeneity in current practice. Current evidence is not robust enough to harmonize current treatment strategies into (inter)national guidelines. What is Known: • Patent ductus arteriosus (PDA) incidence is inversely related to gestational age. • Although early pharmacological treatment induces PDA closure, optimal treatment is debated due to the lack of beneficial effects on outcome. What is New: • In the absence of (inter)national guidelines, diagnostic and treatment strategies are heterogeneous and contradictory, even in a selected hemodynamically- interested group. • Different PDA screening strategies did, while PDA publication status did not, show significant differences in treatment strategy and responses to equipoise statements.

Decreased plasma levels of PDGF-BB, VEGF-A, and HIF-2α in preterm infants after ibuprofen treatment

INTRODUCTION

Ibuprofen is one of the most common non-steroidal anti-inflammatory drugs used to close patent ductus arteriosus (PDA) in preterm infants. PDA is associated with bronchopulmonary dysplasia (BPD), while PDA closure by ibuprofen did not reduce the incidence of BPD or death. Previous studies have indicated an anti-angiogenesis effect of ibuprofen. This study investigated the change of angiogenic factors after ibuprofen treatment in preterm infants.

METHODS

Preterm infants with hemodynamically significant PDA (hsPDA) were included. After confirmed hsPDA by color doppler ultrasonography within 1 week after birth, infants received oral ibuprofen for three continuous days. Paired plasma before and after the ibuprofen treatment was collected and measured by ELISA to determine the concentrations of platelet-derived growth factor-BB (PDGF-BB) and vascular endothelial growth factor A (VEGF-A), and hypoxia-inducible factor-2α (HIF-2α).

RESULTS

17 paired plasma from infants with hsPDA were collected. The concentration of PDGF-BB and VEGF-A significantly decreased after ibuprofen treatment (1,908 vs. 442 pg/mL for PDGF-BB, 379 vs. 174 pg/mL for VEGF-A). HIF-2α level showed a tendency to decrease after ibuprofen treatment, although the reduction was not statistically significant (p = 0.077).

CONCLUSION

This study demonstrated decreased vascular growth factors after ibuprofen exposure in hsPDA infants.

Patent ductus arteriosus: From pharmacology to surgery

Patent ductus arteriosus (PDA) may be found in 0.1-0.2% of term infants, but the average incidence is at least five-fold higher in premature infants, correlating inversely with birth weight and gestational age. While not all patients with a PDA require treatment, the deleterious effects of persistent left-to-right shunting across the ductus can have important short- and long-term consequences. Medical and interventional approaches to PDA closure have evolved greatly in the past decade and add to the decision-making pathways. This article summarizes the pathophysiology of PDA and characterizes the medical, surgical and endovascular treatment approaches.

Artificial intelligence model comparison for risk factor analysis of patent ductus arteriosus in nationwide very low birth weight infants cohort

Despite the many comorbidities and high mortality rate in preterm infants with patent ductus arteriosus (PDA), therapeutic strategies vary depending on the clinical setting, and most studies of the related risk factors are based on small sample populations. We aimed to compare the performance of artificial intelligence (AI) analysis with that of conventional analysis to identify risk factors associated with symptomatic PDA (sPDA) in very low birth weight infants. This nationwide cohort study included 8369 very low birth weight (VLBW) infants. The participants were divided into an sPDA group and an asymptomatic PDA or spontaneously close PDA (nPDA) group. The sPDA group was further divided into treated and untreated subgroups. A total of 47 perinatal risk factors were collected and analyzed. Multiple logistic regression was used as a standard analytic tool, and five AI algorithms were used to identify the factors associated with sPDA. Combining a large database of risk factors from nationwide registries and AI techniques achieved higher accuracy and better performance of the PDA prediction tasks, and the ensemble methods showed the best performances.

An Update on the Prevention and Management of Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is a common morbidity affecting preterm infants and is associated with substantial long-term disabilities. There has been no change in the incidence of BPD over the past 20 years, despite improvements in survival and other outcomes. The preterm lung is vulnerable to injuries occurring as a result of invasive ventilation, hyperoxia, and infections that contribute to the development of BPD. Clinicians caring for infants in the neonatal intensive care unit use multiple therapies for the prevention and management of BPD. Non-invasive ventilation strategies and surfactant administration via thin catheters are treatment approaches that aim to avoid volutrauma and barotrauma to the preterm developing lung. Identifying high-risk infants to receive postnatal corticosteroids and undergo patent ductus arteriosus closure may help to individualize care and promote improved lung outcomes. In infants with established BPD, outpatient management is complex and requires coordination from several specialists and therapists. However, most current therapies used to prevent and manage BPD lack solid evidence to support their effectiveness. Further research is needed with appropriately defined outcomes to develop effective therapies and impact the incidence of BPD.

Fluid status in the first 10 days of life and death/bronchopulmonary dysplasia among preterm infants

OBJECTIVE

To investigate the association between fluid and sodium status in the first 10 postnatal days and death/bronchopulmonary dysplasia (BPD) among infants born <29 weeks' gestation.

STUDY DESIGN

Single center retrospective cohort study (2015-2018) of infants born 23-28 weeks'. Three exposure variables were evaluated over the first 10 postnatal days: cumulative fluid balance (CFB), median serum sodium concentration, and maximum percentage weight loss. Primary outcome was death and/or BPD. Multivariable logistic regression adjusting for patient covariates was used to assess the association between exposure variables and outcomes.

RESULTS

Of 191 infants included, 98 (51%) had death/BPD. Only CFB differed significantly between BPD-free survivors and infants with death/BPD: 4.71 dL/kg (IQR 4.10-5.12) vs 5.11 dL/kg (IQR 4.47-6.07; p < 0.001). In adjusted analyses, we found an association between higher CFB and higher odds of death/BPD (AOR 1.56, 95% CI 1.11-2.25). This was mainly due to the association of CFB with BPD (AOR 1.60, 95% CI 1.12-2.35), rather than with death (AOR 1.08, 95% CI 0.54-2.30).

CONCLUSION

Among preterm infants, a higher CFB in the first 10 days after delivery is associated with higher odds of death/BPD.

IMPACT

Previous studies suggest that postnatal fluid status influences survival and respiratory function in neonates. Fluid balance, serum sodium concentration, and daily weight changes are commonly used as fluid status indicators in neonates. We found that higher cumulative fluid balance in the first 10 days of life was associated with higher odds of death/bronchopulmonary dysplasia in neonates born <29 weeks. Monitoring of postnatal fluid balance may be an appropriate non-invasive strategy to favor survival without bronchopulmonary dysplasia. We developed a cumulative fluid balance chart with corresponding thresholds on each day to help design future trials and guide clinicians in fluid management.

Changes in Patent Ductus Arteriosus Treatment Strategy and Respiratory Outcomes in Premature Infants

OBJECTIVE

To evaluate whether change in patent ductus arteriosus (PDA) management strategies over time had an impact on respiratory outcomes in premature infants.

STUDY DESIGN

Prospectively collected data were included from all preterm infants born at 23-30 weeks gestational age with PDA admitted to the Children's Hospital of the University of Miami/Jackson Memorial Medical Center from January 1, 2005 to December 31, 2007 (epoch 1) and January 1, 2011 to December 31, 2015 (epoch 2). The 2 epochs were compared for approach with PDA diagnosis and subsequent management strategies and respiratory outcomes.

RESULTS

Significantly fewer infants were treated for PDA in epoch 2 (54%) compared with epoch 1 (90%). Multivariable logistic regression analysis demonstrated that infants in epoch 2, with later PDA diagnosis and less frequent PDA treatment, had greater odds of bronchopulmonary dysplasia (BPD), composite of BPD or death, and more treatment with postnatal steroids than in epoch 1.

CONCLUSIONS

The change in approach to diagnosis and management of PDA, from a more proactive and aggressive approach during the earlier epoch 1 to a more expectant approach during the subsequent epoch 2, was associated with worse respiratory outcomes, including increase in BPD and in BPD or death.

Early pulmonary hypertension is a risk factor for bronchopulmonary dysplasia-associated late pulmonary hypertension in extremely preterm infants

This study evaluated whether early pulmonary hypertension (PH) in extremely preterm infants (EPIs) at 22–27 weeks of gestation detected clinically with echocardiography at 4–7 postnatal days (PND) is a risk factor for death before 36 weeks post-menstrual age (PMA) or late PH in moderate or severe (m/s) bronchopulmonary dysplasia (BPD) (BPD-PH). We analyzed risk factors for death before 36 weeks PMA or BPD-PH. Among 247 EPIs enrolled, 74 (30.0%) had early PH. Twenty-one (28.4%) infants with early PH and 18 (10.4%) without early PH died before 36 weeks PMA; 14 (18.9%) infants with early PH and 9 (5.2%) without early PH had BPD-PH at 36–38 weeks PMA. Multivariate analysis revealed that early PH (adjusted odds ratio, 6.55; 95% confidence interval, 3.10–13.82, P < 0.05), clinical chorioamnionitis (2.50; 1.18–5.31), intraventricular hemorrhage (grade 3–4) (3.43; 1.26–9.37), and late sepsis (6.76; 3.20–14.28) independently increased the risk of development of death before 36 weeks PMA or BPD-PH. Subgroup analysis among m/s BPD patients revealed that early PH (4.50; 1.61–12.58) and prolonged invasive ventilator care (> 28 days) (4.91; 1.02–23.68) increased the risk for late PH independently. In conclusion, EPIs with early PH at 4–7 PND should be monitored for BPD-associated late PH development.

Patent ductus arteriosus treatment trends and associated morbidities in neonates

To evaluate national epidemiologic data on infants treated for patent ductus arteriosus (PDA) in Korea and analyze outcomes associated with different PDA treatments. We retrospectively evaluated data on 12,336 patients diagnosed with PDA (International Classification of Diseases-10 code: Q250) between 2015 and 2018 from the Health Insurance Review and Assessment database. Among them, 1623 patients underwent surgical ligation (code: O1671). We used birth certificate data from Statistics Korea to estimate the prevalence, diagnosis, and treatment of PDA. The prevalence of infants with PDA was 81 infants per 10,000 live births and 45.2% in very low birth weight (VLBW) infants, which increased from 2015 to 2018. PDA ligation was performed in 2571 infants and 22% VLBW infants. Medical treatment was administered to 4202 infants, which decreased significantly, especially in VLBW infants (62% to 53%). The proportion of treatment was as follows: conservative treatment (53.1%), intravenous ibuprofen (24.4%), surgery (20.4%), and oral ibuprofen (10.7%); that among 4854 VLBW infants was as follows: intravenous ibuprofen (46.3%), conservative treatment (33.2%), surgery (22.2%), and oral ibuprofen (14.2%). Surgical treatment had a significantly higher risk (odds ratio 1.36) of mortality than conservative treatment. Surgical and/or medical treatments were associated with a higher risk of morbidity. Recently, increased use of conservative management of PDA has contributed to improved neonatal outcomes in VLBW infants. Select patients may still benefit from surgical ligation following careful consideration.

Relative effectiveness and safety of pharmacotherapeutic agents for patent ductus arteriosus (PDA) in preterm infants: a protocol for a multicentre comparative effectiveness study (CANRxPDA)

INTRODUCTION

Patent ductus arteriosus (PDA) is the most common cardiovascular problem that develops in preterm infants and evidence regarding the best treatment approach is lacking. Currently available medical options to treat a PDA include indomethacin, ibuprofen or acetaminophen. Wide variation exists in PDA treatment practices across Canada. In view of this large practice variation across Canadian neonatal intensive care units (NICUs), we plan to conduct a comparative effectiveness study of the different pharmacotherapeutic agents used to treat the PDA in preterm infants.

METHODS AND ANALYSIS

A multicentre prospective observational comparative-effectiveness research study of extremely preterm infants born <29 weeks gestational age with an echocardiography confirmed PDA will be conducted. All participating sites will self-select and adhere to one of the following primary pharmacotherapy protocols for all preterm babies who are deemed to require treatment.Standard dose ibuprofen (10 mg/kg followed by two doses of 5 mg/kg at 24 hours intervals) irrespective of postnatal age (oral/intravenous).Adjustable dose ibuprofen (oral/intravenous) (10 mg/kg followed by two doses of 5 mg/kg at 24 hours intervals if treated within the first 7 days after birth. Higher doses of ibuprofen up to 20 mg/kg followed by two doses of 10 mg/kg at 24 hours intervals if treated after the postnatal age cut-off for lower dose as per the local centre policy).Acetaminophen (oral/intravenous) (15 mg/kg every 6 hours) for 3-7 days.Intravenous indomethacin (0.1-0.3 mg/kg intravenous every 12-24 hours for a total of three doses).

OUTCOMES

The primary outcome is failure of primary pharmacotherapy (defined as need for further medical and/or surgical/interventional treatment following an initial course of pharmacotherapy). The secondary outcomes include components of the primary outcome as well as clinical outcomes related to response to treatment or adverse effects of treatment.

SITES AND SAMPLE SIZE

The study will be conducted in 22 NICUs across Canada with an anticipated enrollment of 1350 extremely preterm infants over 3 years.

ANALYSIS

To examine the relative effectiveness of the four treatment strategies, the primary outcome will be compared pairwise between the treatment groups using χ² test. Secondary outcomes will be compared pairwise between the treatment groups using χ² test, Student's t-test or Wilcoxon rank sum test as appropriate. To further examine differences in the primary and secondary outcomes between the four groups, multiple logistic or linear regression models will be applied for each outcome on the treatment groups, adjusted for potential confounders using generalised estimating equations to account for within-unit-clustering. As a sensitivity analysis, the difference in the primary and secondary outcomes between the treatment groups will also be examined using propensity score method with inverse probability weighting approach.

ETHICS AND DISSEMINATION

The study has been approved by the IWK Research Ethics Board (#1025627) as well as the respective institutional review boards of the participating centres.

TRIAL REGISTRATION NUMBER

NCT04347720.

Acetaminophen Therapy for Persistent Patent Ductus Arteriosus

Persistence of a left-to-right shunt caused by a patent ductus arteriosus (PDA) leads to significant sequelae in extremely premature infants as a result of pulmonary overcirculation and systemic steal. Although timing and duration of treatment for a persistent clinically significant PDA differ among institutions, standard pharmacologic interventions are the nonsteroidal anti-inflammatory drugs indomethacin and ibuprofen. Acetaminophen has emerged as an alternative to indomethacin and ibuprofen with less significant adverse effects, but there is no consensus regarding its use. This review summarizes the most recent evidence for the use of acetaminophen in PDA treatment.

Comparison of standard versus high-dose ibuprofen for the treatment of hemodynamically significant patent ductus arteriosus in preterm infants

OBJECTIVE

To evaluate the effectiveness and safety of standard vs. high-dose ibuprofen for the treatment of hemodynamically significant patent ductus arteriosus(hs-PDA).

STUDY DESIGN

A retrospective study of preterm infants who received either standard (10-5-5 mg/kg/day) or high (postnatal age 1-3 days: 10-5-5 mg/kg/day; 3-5 days: 15-7.5-7.5 mg/kg/day; >5 days: 20-10-10 mg/kg/day) dose ibuprofen for hs-PDA was conducted.

RESULT

Sixty preterm infants with a mean birthweight of 898.2 (±262.6) g and mean gestational age of 26.3 (±0.6) weeks were included. High-dose ibuprofen was associated with a 21%(95% CI, -1.87 to 39.06%; p = 0.07) absolute reduction in PDA ligation compared to standard-dose ibuprofen. On adjusted analysis, receipt of standard-dose ibuprofen (OR 7.37, 95% CI, 1.2-45.27; p = 0.03) independently predicted increased PDA ligation risk. There were no differences in oliguria, NEC, or BPD between groups.

CONCLUSION

High-dose ibuprofen may significantly reduce PDA ligations. No difference in the safety profile with high-dose ibuprofen as compared to the standard-dose regimen was demonstrated.

Primary Pulmonary Vein Stenosis: A New Look at a Rare but Challenging Disease

Primary pulmonary vein stenosis (PPVS) represents a rare but emerging, often progressive heterogeneous disease with high morbidity and mortality in the pediatric population. Although our understanding of PPVS disease has improved markedly in recent years, much remains unknown regarding disease pathogenesis, distinct disease phenotypes, and patient- and disease-related risk factors driving the unrelenting disease progression characteristic of PPVS. In the pediatric population, risk factors identified in the development of PPVS include an underlying congenital heart disease, prematurity and associated conditions, and an underlying genetic or congenital syndrome. Continued improvement in the survival of high-risk populations, coupled with ongoing advances in general PPVS awareness and diagnostic imaging technologies suggest that PPVS will be an increasingly prevalent disease affecting pediatric populations in the years to come. However, significant challenges persist in both the diagnosis and management of PPVS. Standardized definitions and risk stratification for PPVS are lacking. Furthermore, evidence-based guidelines for screening, monitoring, and treatment remain to be established. Given these limitations, significant practice variation in management approaches has emerged across centers, and contemporary outcomes for patients affected by PPVS remain guarded. To improve care and outcomes for PPVS patients, the development and implementation of universal definitions for disease and severity, as well as evidence-based guidelines for screening, monitoring, cardiorespiratory care, and indications for surgical intervention will be critical. In addition, collaboration across institutions will be paramount in the creation of regionalized referral centers as well as a comprehensive patient registry for those requiring pulmonary vein stenosis.

Patent ductus arteriosus management and the drift towards therapeutic nihilism - What is the evidence?

The published literature on patent ductus arteriosus (PDA) management is challenging to interpret due to poorly designed trials with high rates of open label treatments, homogenisation of patients with varying physiological subtypes, poor treatment efficacy, and spontaneous closure in more mature infants. The perceived lack of clinical benefit has led to a drift away from medical and surgical treatment of all infants with a PDA. This therapeutic nihilism as a default response to PDA management fails to recognise the physiological relevance of a left-to-right shunt with early haemodynamic instability after birth and subsequent pulmonary volume overload with prolonged exposure. Clinicians need to know if therapeutic nihilism is safe. This review will provide an overview of the available data on the efficacy of known PDA treatments, conservative management and supportive care measures that are currently applied.

Prolonged Tracheal Intubation and the Association Between Patent Ductus Arteriosus and Bronchopulmonary Dysplasia: A Secondary Analysis of the PDA-TOLERATE trial

In the PDA-TOLERATE trial, persistent (even for several weeks) moderate to large patent ductus arteriosus (PDA) was not associated with an increased risk of BPD when the infant required <10 days of intubation. However, in infants requiring intubation for ≥10 days, prolonged PDA exposure (≥11 days) was associated with an increased risk of moderate/severe BPD.

Conservative Management of Patent Ductus Arteriosus in Preterm Infants-A Systematic Review and Meta-Analyses Assessing Differences in Outcome Measures Between Randomized Controlled Trials and Cohort Studies

Objective: This study aims to evaluate outcome after conservative management (no pharmacological/surgical intervention other than fluid restriction, diuretics, or ventilator adjustments) compared with active (pharmacological and/or surgical) treatment for patent ductus arteriosus (PDA) in preterm infants and analyze differences in outcome between randomized controlled trials (RCTs) and cohort studies. Study Design: This is a systematic literature review using PubMed, EMBASE, and Cochrane library. RCTs and cohort studies comparing conservative management with active treatment were included. Meta-analysis was used to compare conservative management with any active (pharmacological and/or surgical), any pharmacological (non-prophylactic and prophylactic), and/or surgical treatment for mortality as primary and major neonatal morbidity as secondary outcome measure. Fixed-effect analysis was used, unless heterogeneity (I ²) was >50%. Outcome is presented as relative risk (RR) with 95% confidence interval. Results: Twelve cohort studies and four RCTs were included, encompassing 41,804 and 720 patients, respectively. In cohort studies, conservative management for PDA was associated with a significantly higher risk for mortality (RR, 1.34 [1.12-1.62]) but a significantly lower risk for bronchopulmonary dysplasia (RR, 0.55 [0.46-0.65]), necrotizing enterocolitis (RR, 0.85 [0.77-0.93]), intraventricular hemorrhage (RR, 0.88 [0.83-0.95]), and retinopathy of prematurity (RR, 0.47 [0.28-0.79]) compared with any active PDA treatment. Meta-analysis of the RCTs revealed no significant differences in outcome between conservative management and active treatment. Conclusion: No differences in mortality or morbidity for conservative management compared with active treatment regimens were observed in RCTs. Findings from cohort studies mainly highlight the lack of high-quality evidence for conservative management for PDA in preterm infants.

Conservative Treatment Without Any Intervention Compared With Other Therapeutic Strategies for Symptomatic Patent Ductus Arteriosus in Extremely Preterm Infants: A Nationwide Cohort Study in Korea

Objective: Although symptomatic treatment is the most preferred treatment strategy for proven symptomatic patent ductus arteriosus (PDA), a considerable number of infants only received conservative treatment without any pharmacological or surgical interventions in the lower gestational age and lower birth weight group in Korea. We compared in-hospital outcomes of infants treated conservatively without any intervention and those of infants managed by other therapeutic strategies in extremely preterm infants with symptomatic PDA. Methods: A prospectively collected cohort study for 2,303 infants with gestational ages <28 weeks from the Korean Neonatal Network database. These infants were classified into four groups according to the presence of PDA-related symptoms and therapeutic treatment strategy: prophylactic treatment group, pre-symptomatic treatment (PST) group, symptomatic treatment (ST) group, and conservative treatment (CT) without any intervention group. Results: In multivariable logistic regression analysis, the risk of death was significantly decreased in the PST group (adjusted odds ratio [aOR] = 0.507; 95% confidence interval [CI] 0.311-0.826) and ST group (aOR = 0.349; 95% CI: 0.230-0.529) compared with the CT group. However, the risk of composite outcome of severe bronchopulmonary dysplasia or death had not increased in the PST group and ST group. Neonatal death due to pulmonary hemorrhage or neurological disease was significantly higher in the CT group than in the PST group or ST group. Conclusion: In extremely preterm infants, who are at highest risk of PDA-related morbidities and mortality, even less interventional approach for PDA can be allowed; the rescued pharmacological or surgical interventions are necessary if they met the criteria for hemodynamically significant PDA.

A Matched Case Control Study of Surgically and Non-surgically Treated Patent Ductus Arteriosus in Extremely Pre-term Infants

Introduction: There are still uncertainties about the timing and indication for surgical ligation of patent ductus arteriosus (PDA) in pre-term infants, where lower gestational age (GA) usually is predictive for surgical treatment. Objective: Our aim was to assess differences in clinical characteristics and outcomes between surgically treated and matched non-surgically treated PDA in extremely pre-term infants. Methods: All extremely pre-term infants born 2010-2016 with surgically treated PDA (Ligated group; n = 44) were compared to non-surgically treated infants (Control group; n = 44) matched for gestational age (+/-1 week) and time of birth (+/-1 month). Perinatal parameters, echocardiographic variables, details of pharmacological PDA treatment, morbidity, and mortality were assessed. Result: Mean GA and birthweight were similar between the Ligated group (24⁺⁵ ± 1⁺³ weeks and 668 ± 170 g) and the Control group (24⁺⁵ ± 1⁺³ weeks and 704 ± 166 g; p = 1.000 and p = 0.319, respectively). Infants in the Ligated group had larger ductal diameters prior to pharmacological treatment, and lack of diameter decrease and PDA closure after treatment (p = 0.022, p = 0.043 and 0.006, respectively). Transfusions, post-natal steroids and invasive respiratory support were more common in the Ligated group. Except for a higher incidence of severe bronchopulmonary dysplasia (BPD) in the Ligated group there were no other differences in outcomes or mortality between the groups. Conclusion: Early large ductal diameter and reduced responsiveness to pharmacological treatment predicted the need for future surgical ligation in this matched cohort study of extremely pre-term infants where the effect of GA and differences in treatment strategies were excluded. Besides an increased incidence of severe BPD in the Ligated group, no other differences in morbidity or mortality were detected.

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.

Does crossover treatment of control subjects invalidate results of randomized trials of patent ductus arteriosus treatment?

Optimal management of patent ductus arteriosus (PDA) in extremely preterm infants remains controversial. There is paucity of evidence on the benefits of PDA treatment in reducing mortality and morbidities in extremely preterm infants. Failure of randomized clinical trials to demonstrate beneficial effects of PDA treatment on outcomes has often been attributed to open treatment of control subjects. This perspective examines the PDA treatment trials to date, with specific focus on rates of and ages of subjects at open rescue treatment. Although these trials demonstrate that ductal closure is significantly increased with treatment, that does not translate to a significant decrease in major morbidities or mortality in premature infants, even when trials with high rates of rescue treatment of controls are excluded. Trials in which enrollment occurred after 7 days of age include insufficient numbers of subjects to evaluate this relationship.

Patent Ductus Arteriosus of the Preterm Infant

Postnatal ductal closure is stimulated by rising oxygen tension and withdrawal of vasodilatory mediators (prostaglandins, nitric oxide, adenosine) and by vasoconstrictors (endothelin-1, catecholamines, contractile prostanoids), ion channels, calcium flux, platelets, morphologic maturity, and a favorable genetic predisposition. A persistently patent ductus arteriosus (PDA) in preterm infants can have clinical consequences. Decreasing pulmonary vascular resistance, especially in extremely low gestational age newborns, increases left-to-right shunting through the ductus and increases pulmonary blood flow further, leading to interstitial pulmonary edema and volume load to the left heart. Potential consequences of left-to-right shunting via a hemodynamically significant patent ductus arteriosus (hsPDA) include increased risk for prolonged ventilation, bronchopulmonary dysplasia, necrotizing enterocolitis or focal intestinal perforation, intraventricular hemorrhage, and death. In the last decade, there has been a trend toward less aggressive treatment of PDA in preterm infants. However, there is a subgroup of infants who will likely benefit from intervention, be it pharmacologic, interventional, or surgical: (1) prophylactic intravenous indomethacin in highly selected extremely low gestational age newborns with PDA (<26 + 0/7 weeks' gestation, <750 g birth weight), (2) early targeted therapy of PDA in selected preterm infants at particular high risk for PDA-associated complications, and (3) PDA ligation, catheter intervention, or oral paracetamol may be considered as rescue options for hsPDA closure. The impact of catheter-based closure of hsPDA on clinical outcomes should be determined in future prospective studies. Finally, we provide a novel treatment algorithm for PDA in preterm infants that integrates the several treatment modalities in a staged approach.

Conservative Non-intervention Approach for Hemodynamically Significant Patent Ductus Arteriosus in Extremely Preterm Infants

While persistent patent ductus arteriosus (PDA) in preterm infants has been known to be associated with increased mortality and morbidities including bronchopulmonary dysplasia, and necrotizing enterocolitis, there is minimal evidence supporting their causal relationships, and most traditional medical and/or surgical treatments have failed to show improvements in these outcomes. As such, the pendulum has swung toward the conservative non-intervention approach for the management of persistent PDA during the last decade; however, the benefits and risks of this approach are unclear. In this mini review, we focused on whom, when, and how to apply the conservative non-intervention approach for persistent PDA, especially in extremely preterm infants.