Treatment to prevent patency of the ductus arteriosus: beneficial or harmful?

Contemporary fluid management, humidity, and patent ductus arteriosus management strategy for premature infants among 336 hospitals in Asia

Objectives

The management of patent ductus arteriosus (PDA) is a critical concern in premature infants, and different hospitals may have varying treatment policies, fluid management strategies, and incubator humidity. The Asian Neonatal Network Collaboration (AsianNeo) collected data on prematurity care details from hospitals across Asian countries. The aim of this study was to provide a survey of the current practices in the management of PDA in premature infants in Asian countries.

Methods

AsianNeo performed a cross-sectional international questionnaire survey in 2022 to assess the human and physical resources of hospitals and clinical management of very preterm infants. The survey covered various aspects of hospitals resources and clinical management, and data were collected from 337 hospitals across Asia. The data collected were used to compare hospitals resources and clinical management of preterm infants between areas and economic status.

Results

The policy of PDA management for preterm infants varied across Asian countries in AsianNeo. Hospitals in Northeast Asia were more likely to perform PDA ligation (p < 0.001) than hospitals in Southeast Asia. Hospitals in Northeast Asia had stricter fluid restrictions in the first 24 h after birth for infants born at <29 weeks gestation (p < 0.001) and on day 14 after birth for infants born at <29 weeks gestation (p < 0.001) compared to hospitals in Southeast Asia. Hospitals in Northeast Asia also had a more humidified environment for infants born between 24 weeks gestation and 25 weeks gestation in the first 72 h after birth (p < 0.001). A logistic regression model predicted that hospitals were more likely to perform PDA ligation for PDA when the hospitals had a stricter fluid planning on day 14 after birth [Odds ratio (OR) of 1.70, p = 0.048], more incubator humidity settings (<80% vs. 80%-89%, OR of 3.35, p = 0.012 and <80% vs. 90%-100%, OR of 5.31, p < 0.001).

Conclusions

In advanced economies and Northeast Asia, neonatologists tend to adopt a more conservative approach towards fluid management, maintain higher incubator humidity settings and inclined to perform surgical ligation for PDA.

Perinatal origins of bronchopulmonary dysplasia-deciphering normal and impaired lung development cell by cell

Bronchopulmonary dysplasia (BPD) is a multifactorial disease occurring as a consequence of premature birth, as well as antenatal and postnatal injury to the developing lung. BPD morbidity and severity depend on a complex interplay between prenatal and postnatal inflammation, mechanical ventilation, and oxygen therapy as well as associated prematurity-related complications. These initial hits result in ill-explored aberrant immune and reparative response, activation of pro-fibrotic and anti-angiogenic factors, which further perpetuate the injury. Histologically, the disease presents primarily by impaired lung development and an arrest in lung microvascular maturation. Consequently, BPD leads to respiratory complications beyond the neonatal period and may result in premature aging of the lung. While the numerous prenatal and postnatal stimuli contributing to BPD pathogenesis are relatively well known, the specific cell populations driving the injury, as well as underlying mechanisms are still not well understood. Recently, an effort to gain a more detailed insight into the cellular composition of the developing lung and its progenitor populations has unfold. Here, we provide an overview of the current knowledge regarding perinatal origin of BPD and discuss underlying mechanisms, as well as novel approaches to study the perturbed lung development.

Fluid restriction in management of patent ductus arteriosus in Italy: a nationwide survey

We aimed at establishing the state of the art in fluid restriction practice in our national setting and providing a foundation for future research efforts. A prospective cross-sectional survey was conducted among all 114 Italian Neonatal Units in order to address conservative management of patent ductus arteriosus (PDA) in preterm infants below 29 weeks' gestational age (GA), with specific regard to fluid restriction. Response rate was 80%. Conservative measures for PDA management are provided in the majority of NICUs and 80% of centers reduce fluid intake in neonates with PDA. No relationship can be found among pharmacologically or surgically treated patients per year and the approach to fluid restriction. The minimum intake administered at regimen when fluid restriction is applied is associated to the ratio between the maximum number of neonates managed pharmacologically and number of admitted < 29 weeks' GA newborns.

CONCLUSION

Our survey shows an extreme variability among centers in terms of use of fluid restriction as a prophylactic tool but also in terms of its use (both opportunity and modality) when a hemodynamically significant PDA is diagnosed. This variability, that can be also found in randomized trials and observational studies, suggests that further evidence is needed to better understand its potential beneficial effects and its potential harms such as dehydration, hypotension, decreased end-organ perfusion, and reduced caloric intake.

WHAT IS KNOWN

• The lack of demonstrable improvement following the treatment of patent ductus arteriosus has recently paved the way to a more conservative approach. • Fluid restriction is the most commonly applied conservative treatment of PDA.

WHAT IS NEW

• Among Italian NICUs an extreme variability in terms of indications, timing and modalities of application of Fluid restriction can be found. • This variability reflects the lack of standardization of this practice and the contrasting evidence on its efficacy.

Covariation of changing patent ductus arteriosus management and preterm infant outcomes in Pediatrix neonatal intensive care units

OBJECTIVE

To test the hypothesis that NICU-specific preterm infant outcomes co-vary with changes in local patent ductus arteriosus (PDA) management.

STUDY DESIGN

This retrospective multicenter study examined NICU-specific aggregated data for infants born 400-1499 g (VLBW) in the Pediatrix Clinical Data Warehouse. For each NICU and each year 2006-2016 we calculated proportion of infants receiving cyclooxygenase inhibitor (COXI) and/or PDA ligation and determined NICU-specific changes in these therapies between consecutive years. We examined relationships between NICU-specific changes in COXI/ligation and concurrent changes in local adjusted in-hospital outcomes.

RESULTS

In 5678 observations of change at 259 NICUs summarizing 78,105 infants, between-year decreases in NICU-specific proportion treated with COXI/ligation were associated with concurrent increases in local mortality and decreases in BPD among infants 400-749 g, and with decreased pulmonary hemorrhage in larger infants.

CONCLUSIONS

NICU-specific adjusted mortality, BPD, and pulmonary hemorrhage rates co-vary with changes in local COXI/ligation rates in some VLBW infant subgroups.

Management of Patent Ductus Arteriosus in Premature Infants in 2020

The patent ductus arteriosus (PDA) is the most commonly found cardiac condition in neonates. While there have been several studies and thousands of publications on the topic, the decision to treat the PDA is still strongly debated among cardiologists, surgeons, and neonatologists. This is in part due to the shortage of long-term benefits with the interventions studied. Practice variations still exist within sub-specialties and centers. This article briefly summarizes the history, embryology and histology of the PDA. It also succinctly discusses the hemodynamic significance of a PDA which builds the framework to review all the available literature on PDA closure in premature infants, though not a paradigm shift just yet; it introduces transcatheter PDA closure (TCPC) as a possible armament to the clinician for this age-old problem.

Ratio of arterial blood pressures at borders of window surrounding systolic peak indicates patent ductus arteriosus in preterm infants

OBJECTIVE

Presence of a patent ductus arteriosus (PDA) in neonates is assessed by echocardiography. Echocardiographic assessment has disadvantages, primarily its discontinuous nature. We hypothesize that the continuously measured ratio of arterial blood pressures (ABP) at the borders of a window surrounding the systolic peak ratio discriminates non-PDA from PDA patients.

APPROACH

Preterm infants (gestational age <32 weeks) with and without PDA were included. Patients were divided into controls (n = 8) and PDA patients (n = 22), the latter with a subset of patients with closed PDA after three doses Ibuprofen (n = 10). For each patient, a six-hour ABP segment from 12 AM to 6 AM on the day of echocardiographic assessment patency or closure of the DA was selected. The mean ratio of the ABP values a samples before and p samples after the systolic peak (R _ABP) was calculated for each segment. If R _ABP < 1, the patient was predicted to have a PDA. The a and p with the least misclassifications were selected (-64 and +104 ms).

MAIN RESULTS

R _ABP was significantly lower in PDA patients (median 0.95, IQR 0.06) compared to controls (median 1.05, IQR 0.10; p = 0.0024). R _ABP correctly predicted 19 out of 22 patients (86.4%) and six out of eight controls (75%). R _ABP increased after closure in nine out of 10 patients (median 1.01, IQR 0.04; p = 0. 0182).

SIGNIFICANCE

R _ABP may discriminate preterm PDA patients from non-PDA patients and can be calculated continuously from clinical data measured during standard of care.

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

IMPORTANCE

Persistent patent ductus arteriosus (PDA) in preterm infants is associated with increased mortality and respiratory morbidities, including bronchopulmonary dysplasia (BPD). Despite recent increasing use of noninterventional approaches, no study to our knowledge has yet directly compared the nonintervention vs pharmacologic treatment for mediating PDA closure for decreasing mortality and preventing BPD.

OBJECTIVE

To determine the noninferiority of nonintervention vs oral ibuprofen treatment for PDA in decreasing BPD incidence or death in very preterm infants.

DESIGN, SETTING, AND PARTICIPANTS

A randomized, double-blind, placebo-controlled, noninferiority clinical trial was conducted on preterm infants (gestational age [GA] 23-30 weeks) with hemodynamically significant PDA (ductal size >1.5 mm plus respiratory support) diagnosed between postnatal days 6 and 14. Participants included 383 infants screened between July 24, 2014, and March 15, 2019.

INTERVENTIONS

Infants were stratified by GA and randomly assigned (1:1) to receive either oral ibuprofen (initial dose of 10 mg/kg followed by a 5-mg/kg dose after 24 hours and a second 5-mg/kg dose after 48 hours) or placebo.

MAIN OUTCOMES AND MEASURES

The primary outcome was BPD or death; the secondary outcomes included major morbidities and ductal closure rates. Per-protocol analysis was used.

RESULTS

Among 383 infants screened for participation, 146 infants were randomly assigned, with 72 in the nonintervention and 70 in the ibuprofen treatment group in the final analyses. The PDA closure rate at 1 week after randomization was significantly higher with ibuprofen (11 [34%]) than nonintervention (2 [7%]) in infants at GA 27 to 30 weeks (P = .007); however, the findings were not significant at GA 23 to 26 weeks (ibuprofen, 3 [8%] vs nonintervention, 1 [2%], P = .34). In addition, the ductal closure rates before hospital discharge (ibuprofen, 62 [89%] vs nonintervention, 59 [82%], P = .27) and device closure (ibuprofen, 2 [3%] vs nonintervention, 4 [6%], P = .40) were not significantly different between the 2 groups. The nonintervention approach was noninferior to ibuprofen treatment in terms of BPD incidence or death (nonintervention, 44%; ibuprofen, 50%; 95% CI, -0.11 to 0.22; noninferiority margin -0.2; P = .51). One infant in the ibuprofen arm received oral ibuprofen backup rescue treatment owing to cardiopulmonary compromise refractory to conservative management, and another infant in the ibuprofen group received surgical ligation; none of the infants in the placebo group received backup treatment.

CONCLUSIONS AND RELEVANCE

Nonintervention showed noninferiority compared with ibuprofen treatment in closing of hemodynamically significant PDA and reduction of BPD or death. The noninferiority of nonintervention over ibuprofen might be attributable to the low efficacy of oral ibuprofen for closing PDA, especially in infants born at 23 to 26 weeks' gestation.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02128191.

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

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

Covariation of Neonatal Intensive Care Unit-Level Patent Ductus Arteriosus Management and In-Neonatal Intensive Care Unit Outcomes Following Preterm Birth

OBJECTIVE

To test the hypothesis that neonatal intensive care unit (NICU)-specific changes in patent ductus arteriosus (PDA) management are associated with changes in local outcomes in preterm infants.

STUDY DESIGN

This retrospective repeated-measures study of aggregated data included infants born 400-1499 g admitted within 2 days of delivery to NICUs participating in the California Perinatal Quality Care Collaborative. The period 2008-2015 was divided into four 2-year epochs. For each epoch and NICU, we calculated proportions of infants receiving cyclooxygenase inhibitor (COXI) or PDA ligation and determined NICU-specific changes in these therapies between consecutive epochs. Generalized estimating equations were used to examine adjusted relationships between NICU-specific changes in PDA management and contemporaneous changes in local outcomes.

RESULTS

We included 642 observations of interepoch change at 119 hospitals summarizing 32 094 infants. NICU-specific changes in COXI use and ligation showed significant dose-response associations with contemporaneous changes in adjusted local outcomes. Each percentage point decrease in NICU-specific proportion treated with either COXI or ligation was associated with a 0.21 percentage point contemporaneous increase in adjusted local in-hospital mortality (95% CI 0.06, 0.33; P = .005) among infants born 400-749 g. In contrast, decreasing NICU-specific ligation rate among infants 1000-1499 g was associated with decreasing adjusted local bronchopulmonary dysplasia (P = .009) and death or bronchopulmonary dysplasia (P = .01).

CONCLUSIONS

NICU-specific outcomes of preterm birth co-vary with local PDA management. Treatment for PDA closure may benefit some infants born 400-749 g. Decreasing NICU-specific rates of COXI use or ligation were not associated with increases in local adjusted rates of examined adverse outcomes in larger preterm infants.

Early treatment versus expectative management of patent ductus arteriosus in preterm infants: a multicentre, randomised, non-inferiority trial in Europe (BeNeDuctus trial)

BACKGROUND

Much controversy exists about the optimal management of a patent ductus arteriosus (PDA) in preterm infants, especially in those born at a gestational age (GA) less than 28 weeks. No causal relationship has been proven between a (haemodynamically significant) PDA and neonatal complications related to pulmonary hyperperfusion and/or systemic hypoperfusion. Although studies show conflicting results, a common understanding is that medical or surgical treatment of a PDA does not seem to reduce the risk of major neonatal morbidities and mortality. As the PDA might have closed spontaneously, treated children are potentially exposed to iatrogenic adverse effects. A conservative approach is gaining interest worldwide, although convincing evidence to support its use is lacking.

METHODS

This multicentre, randomised, non-inferiority trial is conducted in neonatal intensive care units. The study population consists of preterm infants (GA < 28 weeks) with an echocardiographic-confirmed PDA with a transductal diameter > 1.5 mm. Early treatment (between 24 and 72 h postnatal age) with the cyclooxygenase inhibitor (COXi) ibuprofen (IBU) is compared with an expectative management (no intervention intended to close a PDA). The primary outcome is the composite of mortality, and/or necrotising enterocolitis (NEC) Bell stage ≥ IIa, and/or bronchopulmonary dysplasia (BPD) defined as the need for supplemental oxygen, all at a postmenstrual age (PMA) of 36 weeks. Secondary outcome parameters are short term sequelae of cardiovascular failure, comorbidity and adverse events assessed during hospitalization and long-term neurodevelopmental outcome assessed at a corrected age of 2 years. Consequences regarding health economics are evaluated by cost effectiveness analysis and budget impact analysis.

DISCUSSION

As a conservative approach is gaining interest, we investigate whether in preterm infants, born at a GA less than 28 weeks, with a PDA an expectative management is non-inferior to early treatment with IBU regarding to the composite outcome of mortality and/or NEC and/or BPD at a PMA of 36 weeks.

TRIAL REGISTRATION

This trial is registered with the Dutch Trial Register NTR5479 (registered on 19 October 2015), the registry sponsored by the United States National Library of Medicine Clinicaltrials.gov NCT02884219 (registered May 2016) and the European Clinical Trials Database EudraCT 2017-001376-28 .

Patent ductus arteriosus, its treatments, and the risks of pulmonary morbidity

A persistent left-to-right shunt through a patent ductus arteriosus (PDA) increases the rate of hydrostatic fluid filtration into the lung's interstitium, impairs pulmonary mechanics, and prolongs the need for mechanical ventilation. In preclinical trials, pharmacologic PDA closure leads to improved alveolarization and minimizes the impaired postnatal alveolar development that is the pathologic hallmark of bronchopulmonary dysplasia (BPD). Although routine prophylactic treatment of a PDA on the day of birth does not appear to offer any more protection against BPD than delaying treatment for 2-3 days, recent evidence from quality improvement trials suggests that early pharmacologic treatment decreases the incidence of BPD compared with a treatment approach that exposes infants to a moderate-to-large PDA shunt for the first 7-10 days after birth. After the first week, routine pharmacologic treatment (compared with continued PDA exposure) no longer appears to alter the course of BPD development. Evidence from epidemiologic, preclinical, and randomized controlled trials demonstrate that early ductus ligation is an independent risk factor for the development of BPD.

Changing patterns of patent ductus arteriosus surgical ligation in the United States

Optimal management of patent ductus arteriosus (PDA) is unclear. One treatment, surgical ligation, is associated with adverse outcomes. We reviewed data from the Kids' Inpatient Database (2000-2012) to determine if PDA ligation rates: (1) changed over time, (2) varied geographically, or (3) influenced surgical complication rates. In 2012, 47,900 infants <1500g birth weight were born in the United States, including 2,800 undergoing PDA ligation (5.9%). Ligation was more likely in infants <1000g (85.9% vs. 46.2%), and associated with necrotizing enterocolitis (59.2% vs. 37.5%), BPD (54.6% vs. 15.2%), severe intraventricular hemorrhage (16.4% vs. 5.3%), and hospital transfer (37.6% vs. 16.4%). Ligation rates peaked in 2006 at 87.4 per 1000 hospital births, dropping to 58.8 in 2012, and were consistently higher in Western states. Infants undergoing ligation were more likely to experience comorbidities. Rates of ligation-associated vocal cord paralysis increased over time (1.2-3.9%); however, mortality decreased (12.4-6.5%). Thus, PDA ligation has become less frequent, although infants being ligated are smaller and more medically complex. Despite increase in some complications, mortality rates improved perhaps reflecting advances in care.

Trends and variation in management and outcomes of very low-birth-weight infants with patent ductus arteriosus

BACKGROUND

We examined recent trends and interhospital variation in use of indomethacin, ibuprofen, and surgical ligation for patent ductus arteriosus (PDA) in very-low-birth-weight (VLBW) infants.

METHODS

Included in this retrospective study of the Pediatric Hospital Information System database were 13,853 VLBW infants from 19 US children's hospitals, admitted at age < 3 d between 1 January 2005 and 31 December 2014. PDA management and in-hospital outcomes were examined for trends and variation.

RESULTS

PDA was diagnosed in 5,719 (42%) VLBW infants. Cyclooxygenase inhibitors and/or ligation were used in 74% of infants with PDA overall, however studied hospitals varied greatly in PDA management. Odds of any cyclooxygenase inhibitor or surgical treatment for PDA decreased 11% per year during the study period. This was temporally associated with improved survival but also with increasing bronchopulmonary dysplasia, periventricular leukomalacia, retinopathy of prematurity, and acute renal failure in unadjusted analyses. There was no detectable correlation between hospital-specific changes in PDA management and hospital-specific changes in outcomes of preterm birth during the study period.

CONCLUSION

Use of cyclooxygenase inhibitors and ligation for PDA in VLBW infants decreased over a 10-y period at the studied hospitals. Further evidence is needed to assess the impact of this change in PDA management.

Nonsteroidal anti-inflammatory administration and patent ductus arteriosus ligation, a survey of practice preferences at US children's hospitals

We surveyed neonatal leadership at 46 US children's hospitals via web-based survey to identify local preferences and concerns regarding indomethacin prophylaxis, nonsteroidal anti-inflammatory drug (NSAID) treatment, and patent ductus arteriosus (PDA) ligation. We received a 100 % survey response (N = 46). Practice guidelines for prophylactic indomethacin were reported at 28 % of NICUs, for NSAID treatment of PDA at 39 % and for surgical ligation at 27 %. Respondents noted intra-institutional practice variation for indomethacin prophylaxis (33 %), NSAID treatment (70 %), and PDA ligation (73 %). The majority of institutions did not prescribe indomethacin prophylaxis (72 %). For PDA treatment, indomethacin was preferred over ibuprofen (80 %). We validated our survey results via comparison with billing data as documented in the Pediatric Health Information System (PHIS) database, finding that survey responses directly correlated with local billing data (p < 0.0001). At institutions that did not typically administer NSAIDs for PDA closure or surgical PDA ligation, a lack of evidence for their effectiveness in improving long-term outcomes and the risk of treatment-associated adverse effects were the most often cited reasons.

CONCLUSION

No consensus exists among providers at US children's hospitals regarding prophylactic indomethacin, NSAID treatment, or PDA ligation. Lack of evidence and safety concerns play a prominent role.

WHAT IS KNOWN

• NSAIDs and surgical PDA ligation are efficacious in preventing intraventricular hemorrhage (IVH) and closing PDA in preterm infants, but have not been shown to improve long-term respiratory, neurodevelopmental, or mortality outcomes. What is New: • Practice preferences for indomethacin prophylaxis, NSAID, and surgical PDA treatment vary both among and within institutions. Lack of treatment effectiveness and the risk of adverse effects are major concerns.

Indomethacin vs ibuprofen: comparison of efficacy in the setting of conservative therapeutic approach

Indomethacin has been the mainstay for medical closure of patent ductus arteriosus. With its discontinuation, many units shifted to the use ibuprofen. We compared the therapeutic efficacy (successful closure, a priori defined as complete closure or >50% reduction in size) and the impact of the two drugs on neonatal morbidities. Two time epochs were analysed (IV indomethacin, January 2008 to November 2010, and IV ibuprofen lysine, November 2010 to September 2013). Demographic, clinical and echocardiographic data was compared. A total of 101 infants formed the study population, 58 (57.4%, indomethacin epoch) and 43 (42.6%, ibuprofen epoch). The gestational age, birth weight and postnatal age at initial treatment respectively were comparable [26 ± 1.8 vs 26.5 ± 1.9 weeks, 806 ± 183 vs 862 ± 234 g and median 12 (6, 17) vs 11 days (8, 18)]. Successful closure was significantly higher in the indomethacin group [26 (45%) vs 6 (14%), p < 0.01]. The incidence of bronchopulmonary dysplasia (BPD) and discharge in oxygen was comparable. Four infants (all in the ibuprofen group) developed pulmonary hypertension; one required pulmonary vasodilator therapy. Posttreatment serum creatinine was significantly lower in the ibuprofen group. Mortality was higher during the indomethacin epoch. On univariate analysis, the choice of the drug and higher gestational age were associated with successful closure.

CONCLUSION

Indomethacin was more efficacious for ductal closure although did not impact outcomes. Use of staging schema may help understand 'need to treat' and refine therapy.

Effects of therapeutic approach on the neonatal evolution of very low birth weight infants with patent ductus arteriosus

OBJECTIVE

To analyze the effects of treatment approach on the outcomes of newborns (birth weight [BW] < 1,000 g) with patent ductus arteriosus (PDA), from the Brazilian Neonatal Research Network (BNRN) on: death, bronchopulmonary dysplasia (BPD), severe intraventricular hemorrhage (IVH III/IV), retinopathy of prematurity requiring surgical (ROPsur), necrotizing enterocolitis requiring surgery (NECsur), and death/BPD.

METHODS

This was a multicentric, cohort study, retrospective data collection, including newborns (BW < 1000 g) with gestational age (GA) < 33 weeks and echocardiographic diagnosis of PDA, from 16 neonatal units of the BNRN from January 1, 2010 to Dec 31, 2011. Newborns who died or were transferred until the third day of life, and those with presence of congenital malformation or infection were excluded. Groups: G1 - conservative approach (without treatment), G2 - pharmacologic (indomethacin or ibuprofen), G3 - surgical ligation (independent of previous treatment). Factors analyzed: antenatal corticosteroid, cesarean section, BW, GA, 5 min. Apgar score < 4, male gender, Score for Neonatal Acute Physiology Perinatal Extension (SNAPPE II), respiratory distress syndrome (RDS), late sepsis (LS), mechanical ventilation (MV), surfactant (< 2 h of life), and time of MV.

OUTCOMES

death, O2 dependence at 36 weeks (BPD36wks), IVH III/IV, ROPsur, NECsur, and death/BPD36wks.

STATISTICS

Student's t-test, chi-squared test, or Fisher's exact test; Odds ratio (95% CI); logistic binary regression and backward stepwise multiple regression. Software: MedCalc (Medical Calculator) software, version 12.1.4.0. p-values < 0.05 were considered statistically significant.

RESULTS

1,097 newborns were selected and 494 newborns were included: G1 - 187 (37.8%), G2 - 205 (41.5%), and G3 - 102 (20.6%). The highest mortality was observed in G1 (51.3%) and the lowest in G3 (14.7%). The highest frequencies of BPD36wks (70.6%) and ROPsur were observed in G3 (23.5%). The lowest occurrence of death/BPD36wks occurred in G2 (58.0%). Pharmacological (OR 0.29; 95% CI: 0.14-0.62) and conservative (OR 0.34; 95% CI: 0.14-0.79) treatments were protective for the outcome death/BPD36wks.

CONCLUSION

The conservative approach of PDA was associated to high mortality, the surgical approach to the occurrence of BPD36wks and ROPsur, and the pharmacological treatment was protective for the outcome death/BPD36wks.

A randomised placebo-controlled trial of early treatment of the patent ductus arteriosus

OBJECTIVE

Failure of closure of the patent ductus arteriosus (PDA) may be associated with harm. Early cardiac ultrasound-targeted treatment of a large PDA may result in a reduction in adverse outcomes and need for later PDA closure with no increase in adverse effects.

STUDY DESIGN

Multicentre, double-blind, placebo-controlled randomised trial.

SETTING

Three neonatal intensive care units in Australia.

PATIENTS AND INTERVENTIONS

Eligible infants born <29 weeks were screened for a large PDA and received indomethacin or placebo before age 12 h.

MAIN OUTCOME

Death or abnormal cranial ultrasound.

RESULTS

The trial ceased enrolment early due to lack of availability of indomethacin. 164 eligible infants were screened before 12 h; of the 92 infants with a large PDA, 44 were randomised to indomethacin and 48 to placebo. There was no difference in the main outcome between groups. Infants receiving early indomethacin had significantly less early pulmonary haemorrhage (PH) (2% vs 21%), a trend towards less periventricular/intraventricular haemorrhage (PIVH) (4.5% vs 12.5%) and were less likely to receive later open-label treatment for a PDA (20% vs 40%). The 72 non-randomised infants with a small PDA were at low risk of pulmonary haemorrhage and had an 80% spontaneous PDA closure rate.

CONCLUSIONS

Early cardiac ultrasound-targeted treatment of a large PDA is feasible and safe, resulted in a reduction in early pulmonary haemorrhage and later medical treatment but had no effect on the primary outcome of death or abnormal cranial ultrasound.

REGISTERED TRIAL

Australian New Zealand Clinical Trials Registry (ACTRN12608000295347).

Prolonged persistent patent ductus arteriosus: potential perdurable anomalies in premature infants

OBJECTIVE

Patent ductus arteriosus (PDA) is a common condition among preterm infants. Controversy exists regarding the risk-benefit ratio of early closure of PDAs by either medical or surgical treatments. On the other hand, potential morbidities associated with no or delayed closure has not been well studied. The objective of the study was to determine if there is an association of prolonged persistent PDA (PP-PDA) with various morbidities in infants ≤28 weeks or 1250 g.

STUDY DESIGN

This matched case-control analysis includes preterm infants with a diagnosis of PDA over a period of 28 months in a single level III center in the USA. The predictive variable was the presence of a PP-PDA (PDA>3 weeks). Cases were infants with PP-PDA and controls were those with PDA but not PP-PDA (two controls for each case). Outcome variables included days on mechanical ventilation and with oxygen treatment, length of hospital stay, bronchopulmonary dysplasia (BPD), retinopathy of prematurity stage III-V (ROP) necrotizing enterocolitis grade II or more (NEC), delayed growth, direct hyperbilirubinemia >4 mg dl(-1) and osteopenia of prematurity. Data was obtained from database collected prospectively and from the review of clinical records when necessary. Statistics included ANOVA, Kaplan-Meier curves and χ (2). Significance was set at P<0.05.

RESULT

PP-PDA was associated with a significant increase in the number of days of mechanical ventilation, oxygen treatment and length of hospital stay, and in the rates of BPD (60% vs 4.5%), NEC (29% vs 5%), ROP (43% vs 5%), direct hyperbilirubinemia (41% vs 3%), osteopenia (44% vs 6%), parenteral nutrition for >40 days (70% vs 21%), tracheostomy during the hospitalization (15% vs 0%) and delayed growth (70% vs 21%), were also significantly higher in babies with PP-PDA.

CONCLUSION

A prolonged exposure to PDA does not seem to be inconsequential for some infants and is associated with an increase prevalence of severe morbidities with potential long lasting effects.

Patent ductus arteriosus: are current neonatal treatment options better or worse than no treatment at all?

Although a moderate-sized patent ductus arteriosus (PDA) needs to be closed by the time a child is 1-2 years old, there is great uncertainty about whether it needs to be closed during the neonatal period. Although 95% of neonatologists believe that a moderate-sized PDA should be closed if it persists in infants (born before 28 weeks) who still require mechanical ventilation, the number of neonatologists who treat a PDA when it occurs in infants who do not require mechanical ventilation varies widely. Both the high likelihood of spontaneous ductus closure and the absence of randomized controlled trials, specifically addressing the risks and benefits of neonatal ductus closure, add to the current uncertainty. New information suggests that early pharmacologic treatment has several important short-term benefits for the preterm newborn. By contrast, ductus ligation, while eliminating the detrimental effects of a PDA on lung development, may create its own set of morbidities that counteract many of the benefits derived from ductus closure.

Should we definitively abandon prophylaxis for patent ductus arteriosus in preterm new-borns?

Although the prophylactic administration of indomethacin in extremely low-birth weight infants reduces the frequency of patent ductus arteriosus and severe intraventricular hemorrhage, it does not appear to provide any long-term benefit in terms of survival without neurosensory and cognitive outcomes. Considering the increased drug-induced reduction in renal, intestinal, and cerebral blood flow, the use of prophylaxis cannot be routinely recommended in preterm neonates. However, a better understanding of the genetic background of each infant may allow for individualized prophylaxis using NSAIDs and metabolomics.

Patent ductus arteriosus of the preterm infant

A persistently patent ductus arteriosus (PDA) in preterm infants can have significant clinical consequences, particularly during the recovery period from respiratory distress syndrome. With improvement of ventilation and oxygenation, the pulmonary vascular resistance decreases early and rapidly, especially in very immature infants with extremely low birth weight (<1000 g). Subsequently, the left-to-right shunt through the ductus arteriosus (DA) is augmented, thereby increasing pulmonary blood flow, which leads to pulmonary edema and overall worsening of cardiopulmonary status. Prolonged ventilation, with the potential risks of volutrauma, barotrauma, and hyperoxygenation, is strongly associated with the development and severity of bronchopulmonary dysplasia/chronic lung disease. Substantial left-to-right shunting through the ductus may also increase the risk of intraventricular hemorrhage, necrotizing enterocolitis, and death. Postnatal ductal closure is regulated by exposure to oxygen and vasodilators; the ensuing vascular responses, mediated by potassium channels, voltage-gated calcium channels, mitochondrial-derived reactive oxygen species, and endothelin 1, depend on gestational age. Platelets are recruited to the luminal aspect of the DA during closure and probably promote thrombotic sealing of the constricted DA. Currently, it is unclear whether and when a conservative, pharmacologic, or surgical approach for PDA closure may be advantageous. Furthermore, it is unknown if prophylactic and/or symptomatic PDA therapy will cause substantive improvements in outcome. In this article we review the mechanisms underlying DA closure, risk factors and comorbidities of significant DA shunting, and current clinical evidence and areas of uncertainty in the diagnosis and treatment of PDA of the preterm infant.

Indomethacin pharmacodynamics are altered by surfactant: a possible challenge to current indomethacin dosing guidelines created before surfactant availability

The effect of surfactant administration for respiratory distress syndrome (RDS) on indomethacin (INDO) pharmacodynamics and dosing requirements for patent ductus arteriosus (PDA) closure and renal toxicity was evaluated. A 22-year prospective cohort study including 442 INDO-treated patients given 466 INDO treatment courses. The database included demographic information, medical problems, and medications. Neonates with a PDA confirmed by echocardiography were treated with INDO, 0.25-0.3 mg/kg. Subsequent INDO dosing was based on a combined pharmacokinetic/pharmacodynamic (PK/PD) approach. Data were fit to an Emax model and ANOVA was used to compare mean closure levels between groups. PDA closure was successful in 405 of 442 patients (91.6%) and in 434 of 466 treatment courses (93.1%) using an individualized PK/PD dosing approach. Renal toxicity was documented in 56 of 442 patients (12.7%) or 56 of 466 treatment courses (12.0%). Patients not treated with synthetic surfactant trended toward lower mean INDO concentrations at PDA closure compared to patients treated with synthetic surfactant (1.65 vs. 2.01 mg/l; P > 0.05) and significantly lower mean INDO concentrations at PDA closure compared to patients treated with natural surfactant (1.65 vs. 2.15 mg/l; P < 0.002). This requires an increased total dose of ~0.3 mg/kg or an individual dose increase of 0.1 mg/kg. Administration of natural or synthetic surfactant for RDS may increase the INDO concentrations and doses needed for PDA closure in premature infants.

Treatment of persistent patent ductus arteriosus in preterm infants: time to accept the null hypothesis?

Medical and surgical interventions are widely used to close a persistently patent ductus arteriosus in preterm infants. Objective evidence to support these practices is lacking, causing some to question their usage. Emerging evidence suggests that treatments that close the patent ductus may be detrimental. This review examines the history of and evidence underlying these treatments. Neither individual trials, pooled data from groups of randomized-controlled trials, nor critical examination of the immediate consequences of treatment provide evidence that medical or surgical closure of the ductus is beneficial in preterm infants. These conclusions are supported by sufficient evidence. Neither continued routine use of these treatments nor additional clinical trials using similar designs seems to be justified. A definitive trial, comparing current standard management with novel strategies not primarily intended to achieve ductal closure, may be necessary to resolve doubts regarding the quality or conduct of prior studies.

[Patent ductus arteriosus in premature infants]

BACKGROUND

Patent ductus arteriosus in premature infants has often been treated because of its association with worsening of pulmonary disease and complications such as bronchopulmonary dysplasia. This view has now been challenged.

MATERIAL AND METHODS

Relevant publications have been identified from review articles in international peer-reviewed journals. The articles have been retrieved through searches in the PubMed and Cochrane-databases.

RESULTS

Recent research has led to a new understanding of patent ductus arteriosus - a shift of paradigm has occurred. The condition implies that a shunt enables blood to flow from right to left in the first postnatal days (when pulmonary arterial pressure is high), and left to right in cases where significant pulmonary disease is present. The increased pulmonary blood flow improves oxygenation, and the condition should be considered as physiological in small premature infants. A patent ductus arteriosus does not worsen concomitant pulmonary disease or increase the risk of bronchopulmonary dysplasia, intraventricular hemorrhage, necrotising enterocolitis or other complications.

INTERPRETATION

Treatment of a patent ductus arteriosus with COX-inhibitors such as indomethacin and ibuprofen, increases the risk for bronchopulmonary dysplasia without reducing other complications or death. A large patent ductus arteriosus has significant hemodynamic effects and should be treated with fluid restriction, diuretics and inotropic drugs before closure is considered. Surgical closure of a patent ductus arteriosus is linked to neurosensory impairment in survivors.

Vocal fold paralysis following surgical ductal closure in extremely low birth weight infants: a case series of feeding and respiratory complications

Surgical closure of a patent ductus arteriosus (PDA) continues to be a frequent procedure among extremely preterm infants. Recent evidence indicates surgical closure is associated with worse outcomes than after medical closure. Left vocal fold paralysis is a known complication of this surgery, but there is little information available on the impact of this specific complication on long-term outcomes of these infants. In this case series, we describe the clinical course of three sets of multiple births, in which at least one infant underwent surgical closure of the PDA and subsequently developed feeding and/or breathing difficulties due to left vocal fold paralysis, and compare to their siblings who did not sustain this complication. The case series suggests that some long-term morbidities associated with surgical closure of the PDA may be attributable to this specific complication.

Patent ductus arteriosus and its treatment as risk factors for neonatal and neurodevelopmental morbidity

OBJECTIVES

The purpose of this work was to determine whether the reported association between neonatal morbidities and a patent ductus arteriosus is because of the left-to-right patent ductus arteriosus shunt itself, the therapies used to treat it, or the immaturity of the infants who are likely to develop a patent ductus arteriosus.

METHODS

A total of 446 infants (<28 weeks' gestation) were treated with the same patent ductus arteriosus care-oriented protocol, and logistic regression analysis was used to examine the effects of several patent ductus arteriosus-related variables (presence of a symptomatic patent ductus arteriosus, the number of indomethacin doses used, the ductus response to indomethacin, and the use of surgical ligation) on the incidence of retinopathy of prematurity, necrotizing enterocolitis, chronic lung disease, death, and neurodevelopmental impairment.

RESULTS

Most of the predictive effects that the presence of a patent ductus arteriosus and its treatment had on neonatal morbidity could be accounted for by the infants' immature gestation. Use of surgical ligation, however, was significantly associated with the development of chronic lung disease and was independent of immature gestation, other patent ductus arteriosus-related variables, or other perinatal and neonatal risk factors known to be associated with chronic lung disease.

CONCLUSIONS

These findings add to the growing uncertainty about the benefits and risks of surgical ligation during the neonatal period.