Increased indomethacin dosing for persistent patent ductus arteriosus in preterm infants: a multicenter, randomized, controlled trial

Systemic Cytokines in Retinopathy of Prematurity

Retinopathy of prematurity (ROP), a vasoproliferative vitreoretinal disorder, is the leading cause of childhood blindness worldwide. Although angiogenic pathways have been the main focus, cytokine-mediated inflammation is also involved in ROP etiology. Herein, we illustrate the characteristics and actions of all cytokines involved in ROP pathogenesis. The two-phase (vaso-obliteration followed by vasoproliferation) theory outlines the evaluation of cytokines in a time-dependent manner. Levels of cytokines may even differ between the blood and the vitreous. Data from animal models of oxygen-induced retinopathy are also valuable. Although conventional cryotherapy and laser photocoagulation are well established and anti-vascular endothelial growth factor agents are available, less destructive novel therapeutics that can precisely target the signaling pathways are required. Linking the cytokines involved in ROP to other maternal and neonatal diseases and conditions provides insights into the management of ROP. Suppressing disordered retinal angiogenesis via the modulation of hypoxia-inducible factor, supplementation of insulin-like growth factor (IGF)-1/IGF-binding protein 3 complex, erythropoietin, and its derivatives, polyunsaturated fatty acids, and inhibition of secretogranin III have attracted the attention of researchers. Recently, gut microbiota modulation, non-coding RNAs, and gene therapies have shown promise in regulating ROP. These emerging therapeutics can be used to treat preterm infants with ROP.

New Aspects on the Treatment of Retinopathy of Prematurity: Currently Available Therapies and Emerging Novel Therapeutics

Retinopathy of prematurity (ROP) is a rare proliferative ocular disorder in preterm infants. Because of the advancements in neonatal care, the incidence of ROP has increased gradually. Now, ROP is one of the leading causes of blindness in children. Preterm infants with immature retinal development are exposed to supplemental oxygen inside an incubator until their cardiopulmonary system is adequately developed. Once they are returned to room air, the relatively low oxygen level stimulates various angiogenesis factors initiating retinal neovascularization. If patients with ROP are not offered adequate and timely treatment, they can experience vision loss that may ultimately lead to permanent blindness. Although laser therapy and anti-vascular endothelial growth factor agents are widely used to treat ROP, they have limitations. Thus, it is important to identify novel therapeutics with minimal adverse effects for the treatment of ROP. To date, various pharmacologic and non-pharmacologic therapies have been assessed as treatments for ROP. In this review, the major molecular factors involved in the pathogenesis of ROP, currently offered therapies, therapies under investigation, and emerging novel therapeutics of ROP are discussed.

International Variation in the Management of Patent Ductus Arteriosus and Its Association with Infant Outcomes: A Survey and Linked Cohort Study

OBJECTIVE

To assess whether treating patients with a presymptomatic patent ductus arteriosus (PDA), based on early routine echocardiography, performed regardless of clinical signs, improved outcomes.

STUDY DESIGN

This multicenter, survey-linked retrospective cohort study used an institutional-level questionnaire and individual patient-level data and included infants of <29 weeks of gestation born in 2014-2016 and admitted to tertiary neonatal intensive care units (NICUs) of 9 population-based national or regional neonatal networks. Infants in NICUs receiving treatment of presymptomatic PDA identified by routine echocardiography and those not were compared for the primary composite outcome (early death [≤7 days after birth] or severe intraventricular hemorrhage) and secondary outcomes (any in-hospital mortality and major morbidities).

RESULTS

The unit survey (response rates of 86%) revealed a wide variation among networks in the treatment of presymptomatic PDA (7%-86%). Among 246 NICUs with 17 936 infants (mean gestational age of 26 weeks), 126 NICUs (51%) with 7785 infants treated presymptomatic PDA. The primary outcome of early death or severe intraventricular hemorrhage was not significantly different between the NICUs treating presymptomatic PDA and those who did not (17% vs 21%; aOR 1.00, 95% CI 0.85-1.18). The NICUs treating presymptomatic PDA had greater odds of retinopathy of prematurity treatment (13% vs 7%; aOR 1.47, 95% CI 1.01-2.12); however, it was not significant in a sensitivity analysis excluding Japanese data.

CONCLUSIONS

Treating presymptomatic PDA detected by routine echocardiography was commonplace but associated with no significant benefits. Well-designed trials are needed to assess the efficacy and safety of early targeted PDA treatment.

High Dose Indomethacin for Patent Ductus Arteriosus Closure Increases Neonatal Morbidity

OBJECTIVE

Symptomatic patent ductus arteriosus (sPDA) is the most common heart abnormality in preterm infants. Optimal duration and dose of medical treatment is still unclear. We assessed undesired effects and closure rate of high-dose indomethacin (HDI) for pharmacological closure of sPDA.

STUDY DESIGN

Retrospective single center analysis of 248 preterm infants born between January 2006 and December 2015 with a birth weight <2,000 g and sPDA which was treated with indomethacin. Patients were treated with either standard dose indomethacin (SDI; n = 196) or HDI (n = 52). Undesired effects and PDA closure were compared between patients treated with SDI and HDI.

RESULTS

In univariate analysis, patients receiving HDI had a significant increase in gastrointestinal hemorrhage (32.7 vs.11.7%, p = 0.001), bronchopulmonary dysplasia (BPD) (77.8 vs. 55.1%, p = 0.003), and retinopathy of prematurity (13.5 vs. 2.6%, p = 0.004). Moreover, HDI patients needed longer mechanical ventilation (2.5 vs. 1.0 days, p = 0.01). Multivariate analyses indicated that necrotizing enterocolitis (17 vs. 7%, p = 0.01) and BPD (79 vs. 55%, p = 0.02) were more frequent in HDI patients. PDA closure rate was 79.0% with HDI versus 65.3% with SDI.

CONCLUSION

HDI used for PDA closure is associated with an increase in necrotizing enterocolitis and BPD. Risks of HDI should be balanced against other treatment options.

Stable incidence but regional differences in retinopathy of prematurity in Norway from 2009 to 2017

PURPOSE

To explore the changes over time and regional differences in the incidence of retinopathy of prematurity (ROP) in a national cohort of infants born <28 weeks' gestational age (GA).

METHODS

A population-based study of infants with GA <28 weeks in Norway from 2009 to 2017. Prospectively collected data on clinical variables and outcomes were obtained from the Norwegian Neonatal Network.

RESULTS

Of 1499 live-born infants transferred to a neonatal intensive care unit, 1156 were discharged alive. Four-hundred and fifty-eight infants (39.6%) had ROP, 152 (13.1%) had severe ROP, and 110 (9.5%) were treated for ROP. Eleven hundred infants (95.2%) had complete data sets. In a model comprising region of primary care, GA [odds ratios (OR): 0.65; 95% CI: 0.55-0.77], growth velocity (OR: 1.10; 95% CI: 1.00-2.00), medically treated patent ductus arteriosus (OR: 1.80; 95% CI: 1.19-2.72), weeks of supplemental oxygen (OR: 1.07; 95% CI: 1.03 to 1.11) and region of primary care (OR: 4.95; 95% CI: 3.05-8.04 for the pair of regions with the highest estimated OR) were significantly associated with severe ROP. Additionally, institutional differences for severe ROP were found, with ORs from 0.41 (95% CI: 0.05-3.23) to 5.36 (95% CI: 3.05-9.43) using the largest institution as reference. Incidences were stable over time after adjusting for GA. A larger proportion was treated with anti-vascular endothelial growth factor after 2011.

CONCLUSIONS

The incidence of severe ROP was stable between 2009 and 2017 in Norway. Regional and institutional differences need to be explored in future studies.

Translational Research in Retinopathy of Prematurity: From Bedside to Bench and Back Again

Retinopathy of prematurity (ROP), a vascular proliferative disease affecting preterm infants, is a leading cause of childhood blindness. Various studies have investigated the pathogenesis of ROP. Clinical experience indicates that oxygen levels are strongly correlated with ROP development, which led to the development of oxygen-induced retinopathy (OIR) as an animal model of ROP. OIR has been used extensively to investigate the molecular mechanisms underlying ROP and to evaluate the efficacy of new drug candidates. Large clinical trials have demonstrated the efficacy of anti-vascular endothelial growth factor (VEGF) agents to treat ROP, and anti-VEGF therapy is presently becoming the first-line treatment worldwide. Anti-VEGF therapy has advantages over conventional treatments, including being minimally invasive with a low risk of refractive error. However, long-term safety concerns and the risk of late recurrence limit this treatment. There is an unmet medical need for novel ROP therapies, which need to be addressed by safe and minimally invasive therapies. The recent progress in biotechnology has contributed greatly to translational research. In this review, we outline how basic ROP research has evolved with clinical experience and the subsequent emergence of new drugs. We discuss previous and ongoing trials and present the candidate molecules expected to become novel targets.

Bedside surgical ligation of the patent ductus arteriosus in very-low-birth-weight premature infants: Limited upper ministernotomy as an alternative approach

BACKGROUND

Patent ductus arteriosus (PDA) is an important cause of morbidity and mortality, especially in very-low-birth-weight infants. The aim of the present study was to evaluate the outcomes of bedside surgical ligation of PDA via limited upper ministernotomy as an alternative approach to thoracotomy.

MATERIALS AND METHODS

A total of 23 low-birth-weight premature infants, who underwent bedside ligation of PDA in the neonatal intensive care unit between January 2017 and April 2020, were enrolled. The patients were divided into two groups: those with thoracotomy (n = 13) and those with limited upper ministernotomy (n = 10). These patients were evaluated retrospectively in terms of clinical and preoperative, intraoperative, postoperative parameters between the groups.

RESULTS

Mean birth weight was 1059 ± 275 g in the thoracotomy group and 1035 ± 285 g in the ministernotomy group. There was no statistically significant difference in the age at surgery, weight at surgery, preoperative mechanical ventilation (MV) support, inotropic score onset of surgery, and total procedure time between the groups. There was a statistically significant difference in the hospital length of stay, postoperative MV time, and complications in the intensive care unit in favor of the ministernotomy group (p = .04, p = .03, p = .034, respectively). The study showed no statistically significant difference in the mortality rate between the two groups (two patients in the thoracotomy group and one patient in the ministernotomy group).

CONCLUSION

The limited upper ministernotomy is an anatomically and technically feasible alternative to classical left posterolateral thoracotomy for bedside surgical PDA ligation.

Patent ductus arteriosus and cerebral, cardiac, and gut hemodynamics in premature neonates

Patent ductus arteriosus is associated with multiple comorbidities in premature infants, however a causal link or strategy to decrease these morbidities has not been found. The association between the patent ductus arteriosus and morbidities has biologic plausibility as, like any cardiac mixing lesion, a significant systemic to pulmonic shunt may lead to pulmonary over-circulation and systemic hypoperfusion. Understanding the underlying pathophysiology of associated morbidities in the setting of a patent ductus arteriosus may aid in risk stratifying infants and offer a patient targeted approach to infants with a pathological ductal shunt. While the deleterious impact of increased pulmonary blood flow maybe easier to identify, the impact on end-organ perfusion is more challenging. In this review, we will discuss the pathophysiology of a hemodynamically significant patent ductus arteriosus in premature infants, impact on end-organ perfusion and associated morbidities, and novel modalities to assess shunt volume and effect on end-organ perfusion.

A safety review of drugs used for the treatment of retinopathy of prematurity

INTRODUCTION

Retinopathy of Prematurity (ROP) is a sight-threatening disease representing one of the main disabling diseases affecting premature newborns. Presently, ROP is treated by surgical interventions and drug therapies are limited to the off-label use of a little amount of molecules approved for other pathologies.

AREAS COVERED

Many drugs that may potentially be used in treating ROP are recently proposed, in many cases after the demonstration of their effectiveness in preclinical studies. In this review, the authors discuss safety and effectiveness of the main proposed approaches in the pharmacologic treatment of the disease, including approaches based on oxygen therapy and nutritional interventions.

EXPERT OPINION

Surgical approaches to ROP are not without side effects. However, most of the proposed pharmacologic interventions can also raise specific concerns. In particular, these approaches follow a curative paradigm and are proposed in patients once the disease has progressed, with an effectiveness that is often smaller than expected. A goal in the treatment of ROP would be moving the paradigm toward a preventive approach that could be potentially effective in treating extremely low birth weight preterm infants before ROP becomes manifest.

Survey of PDA management in very low birth weight infants across Italy

Background

The optimal management of PDA in very low birth weight (VLBW) infants is still controversial. Aim of our study was to investigate the management of PDA in the Italian neonatal intensive care units (NICU).

Methods

We conducted an on-line survey study from June to September 2017. A 50-items questionnaire was developed by the Italian Neonatal Cardiology Study Group and was sent to Italian NICUs.

Results

The overall response rate was 72%. Diagnosis of PDA was done by neonatologists, cardiologists or both (62, 12 and 28% respectively). PDA significance was assessed by a comprehensive approach in all centers, although we found a heterogeneous combination of parameters and cut-offs used. None used prophylactic treatment. 19% of centers treated PDA in the first 24 h, 60% after the first 24 h, following screening echocardiography or clinical symptoms, 18% after the first 72 h and 2% after the first week. In the first course of treatment ibuprofen, indomethacin and paracetamol were used in 87, 6 and 7% of centers respectively. Median of surgical ligation was 3% (1–6%).

Conclusions

Significant variations exist in the management of PDA in Italy. Conservative strategy and targeted treatment to infants older than 24 h with echocardiographic signs of hemodynamic significance seemed to be the most adopted approach.

Indomethacin dosing strategy and neonatal patent ductus arteriosus closure

BACKGROUND

Few studies exist that have evaluated the effects of indomethacin dosing frequency as a factor associated with successful patent ductus arteriosus closure in very low birth weight neonates. The objective of this study is to determine if indomethacin dosing strategy is associated with efficacy for initial patent ductus arteriosus management in very low birth weight neonates.

METHODS

This retrospective review compared every 12 hour and every 24 hour indomethacin regimens primarily for efficacy in initial patent ductus arteriosus management, defined as an absence of repeat medical and/or surgical treatment, and secondarily for safety in both univariate and multivariate models.

RESULTS

One hundred three very low birth weight neonates were included: 56 (54%) received every 12 hour and 47 (46%) underwent every 24 hour indomethacin dosing. Repeat medical and/or surgical patent ductus arteriosus treatment rates were similar between groups. Less ligation of the patent ductus arteriosus occurred with every 12 hour versus every 24 hour dosing (11% vs. 26%, p = 0.05), though this effect was mitigated controlling for birth weight and gestational age. Renal function, respiratory outcomes, feeding outcomes, length of stay, and mortality were similar between groups.

CONCLUSIONS

Neither the every 12 hour nor the every 24 hour indomethacin regimen demonstrated inferior efficacy or safety for initial management of patent ductus arteriosus. Further prospective analysis of indomethacin dosing strategy is warranted.

Retinopathy of prematurity: a review of risk factors and their clinical significance

Retinopathy of prematurity (ROP) is a retinal vasoproliferative disease that affects premature infants. Despite improvements in neonatal care and management guidelines, ROP remains a leading cause of childhood blindness worldwide. Current screening guidelines are primarily based on two risk factors: birth weight and gestational age; however, many investigators have suggested other risk factors, including maternal factors, prenatal and perinatal factors, demographics, medical interventions, comorbidities of prematurity, nutrition, and genetic factors. We review the existing literature addressing various possible ROP risk factors. Although there have been contradictory reports, and the risk may vary between different populations, understanding ROP risk factors is essential to develop predictive models, to gain insights into pathophysiology of retinal vascular diseases and diseases of prematurity, and to determine future directions in management of and research in ROP.

Association of Placebo, Indomethacin, Ibuprofen, and Acetaminophen With Closure of Hemodynamically Significant Patent Ductus Arteriosus in Preterm Infants: A Systematic Review and Meta-analysis

IMPORTANCE

Despite increasing emphasis on conservative management of patent ductus arteriosus (PDA) in preterm infants, different pharmacotherapeutic interventions are used to treat those developing a hemodynamically significant PDA.

OBJECTIVES

To estimate the relative likelihood of hemodynamically significant PDA closure with common pharmacotherapeutic interventions and to compare adverse event rates.

DATA SOURCES AND STUDY SELECTION

The databases of MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials were searched from inception until August 15, 2015, and updated on December 31, 2017, along with conference proceedings up to December 2017. Randomized clinical trials that enrolled preterm infants with a gestational age younger than 37 weeks treated with intravenous or oral indomethacin, ibuprofen, or acetaminophen vs each other, placebo, or no treatment for a clinically or echocardiographically diagnosed hemodynamically significant PDA.

DATA EXTRACTION AND SYNTHESIS

Data were independently extracted in pairs by 6 reviewers and synthesized with Bayesian random-effects network meta-analyses.

MAIN OUTCOMES AND MEASURES

Primary outcome: hemodynamically significant PDA closure; secondary: included surgical closure, mortality, necrotizing enterocolitis, and intraventricular hemorrhage.

RESULTS

In 68 randomized clinical trials of 4802 infants, 14 different variations of indomethacin, ibuprofen, or acetaminophen were used as treatment modalities. The overall PDA closure rate was 67.4% (2867 of 4256 infants). A high dose of oral ibuprofen was associated with a significantly higher odds of PDA closure vs a standard dose of intravenous ibuprofen (odds ratio [OR], 3.59; 95% credible interval [CrI], 1.64-8.17; absolute risk difference, 199 [95% CrI, 95-258] more per 1000 infants) and a standard dose of intravenous indomethacin (OR, 2.35 [95% CrI, 1.08-5.31]; absolute risk difference, 124 [95% CrI, 14-188] more per 1000 infants). Based on the ranking statistics, a high dose of oral ibuprofen ranked as the best pharmacotherapeutic option for PDA closure (mean surface under the cumulative ranking [SUCRA] curve, 0.89 [SD, 0.12]) and to prevent surgical PDA ligation (mean SUCRA, 0.98 [SD, 0.08]). There was no significant difference in the odds of mortality, necrotizing enterocolitis, or intraventricular hemorrhage with use of placebo or no treatment compared with any of the other treatment modalities.

CONCLUSIONS AND RELEVANCE

A high dose of oral ibuprofen was associated with a higher likelihood of hemodynamically significant PDA closure vs standard doses of intravenous ibuprofen or intravenous indomethacin; placebo or no treatment did not significantly change the likelihood of mortality, necrotizing enterocolitis, or intraventricular hemorrhage.

TRIAL REGISTRATION

PROSPERO Identifier: CRD42015015797.

Non-steroidal Anti-inflammatory Drugs in Newborns and Infants

Nonsteroidal antiinflammatory drugs (NSAIDs) and acetaminophen are used in young infants and newborns for pain and fever control, patent ductus closure, prevention of intraventricular hemorrhage, and potentially for prevention of retinopathy of prematurity. These drugs inhibit cyclooxygenase 1 (COX-1), COX-2, and peroxidases, thus, blocking prostaglandin (PG) synthesis. PGs are eicosanoids that regulate several physiologic, pathologic, and cellular processes, including vasomotor tone, platelet aggregation, sensitization of neurons to pain, and many molecular events critical to physiologic homeostasis. NSAIDs inhibit caspases and cell death. Increasing knowledge of these molecular entities may allow targeted drug development to prevent or minimize neonatal morbidities.

Pharmacologic interventions for the prevention and treatment of retinopathy of prematurity

Retinopathy of prematurity (ROP), a significant morbidity in prematurely born infants, is the most common cause of visual impairment and blindness in children and persists till adulthood. Strict control of oxygen therapy and prevention of intermittent hypoxia are the keys in the prevention of ROP, but pharmacologic interventions have decreased risk of ROP. Various drug classes such as methylxanthines (caffeine), VEGF inhibitors, antioxidants, and others have decreased ROP occurrence. The timing of pharmacologic intervention remains unsettled, but early prevention rather than controlling disease progression may be preferred. These drugs act through different mechanisms, and synergistic approaches should be considered to maximize efficacy and safety.

Retinopathy of prematurity: Risk factors and variability in Canadian neonatal intensive care units

OBJECTIVE

To identify predictors of severe retinopathy of prematurity (ROP) in a large population-based cohort and to examine risk-adjusted variations across units.

STUDY DESIGN

Retrospective analysis of Canadian Neonatal Network data on neonates with birth weight <1500 g who were screened for ROP between 2003 and 2010. Characteristics of infants with and without ROP were compared and a risk-adjusted model for severe ROP was developed. Rates of severe ROP were compared between sites.

RESULTS

1163 of 9187 (12.7%) infants developed severe ROP. Lower gestational age, male sex, small for gestational age, patent ductus arteriosus, late onset sepsis, more than two blood transfusions, inotrope use, and outborn status were associated with an increased risk of severe ROP. Severe ROP rates varied significantly between units.

CONCLUSION

Younger, smaller and sicker male infants had higher adjusted risks of severe ROP and rates varied significantly among sites.

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

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

What is wrong with meta-analysis? The importance of clinical heterogeneity in myocardial regeneration research

The author discusses the significance and potential pitfalls in performing a meta-analysis underscoring the importance of a usual forgotten issue in meta-analysis called clinical heterogeneity. Clinical heterogeneity can mislead results and misinform clinicians. Practical examples from the literature are given, and the results of meta-analyses are compared with the results of subsequent large randomised clinical trials addressing similar questions from a historical and contemporary point of view, highlighting clinical heterogeneity. The contemporary aspect culminates with the presentation of a meta-analysis evaluating myocardial cell regeneration with an emphasis in clinical heterogeneity, helping clinicians to understand the issue and better appraise future meta-analyses.

Patent ductus arteriosus and indomethacin treatment as independent risk factors for plus disease in retinopathy of prematurity

PURPOSE

To examine whether clinically significant patent ductus arteriosus (PDA) or indomethacin treatment are associated with plus disease or retinopathy of prematurity (ROP) requiring treatment.

METHODS

Retrospective, cross-sectional study. Charts were reviewed for gestational age, birth weight, birth head circumference, birth length, maternal characteristics, gender, bronchopulmonary dysplasia, neurologic comorbidities, PDA and its treatments, gastrointestinal comorbidities, blood transfusions, and sepsis. Main outcome measures were increased rates of plus disease or ROP requiring treatment.

RESULTS

A total of 450 premature infants screened for ROP in a mid-sized, urban neonatal intensive care unit were included. On univariate analysis, gestational age, birth weight, birth head circumference, birth length, bronchopulmonary dysplasia, neurologic comorbidities, PDA and its treatments, gastrointestinal comorbidities, and sepsis were significantly correlated to plus disease and ROP requiring treatment. PDA was significantly associated with bronchopulmonary dysplasia, neurologic comorbidities, sepsis, and blood transfusions (P < .0001). With type 3 multivariate analysis, only gestational age and bronchopulmonary dysplasia were independent risk factors for ROP.

CONCLUSION

PDA and indomethacin were associated with plus disease and ROP requiring treatment on univariate analysis but this was not significant after adjusting for other risk factors. PDA was also strongly related to bronchopulmonary dysplasia and blood transfusions, which may explain its effect on ROP.

Deleterious effects of indomethacin in the mid-gestation human intestine

The use of the anti-inflammatory drug indomethacin (INDO) in preterm infants has been associated with an increased risk of developing enteropathies. In this study, we have investigated the direct impact of INDO on the human mid-gestation intestinal transcriptome using serum-free organ culture. After determining the optimal dose of 1 μM of INDO (90% inhibition of intestinal prostaglandin E2 production and range of circulating levels in treated preterm babies), global gene expression profiles were determined using Illumina bead chip microarrays in both small and large intestines after 48 h of INDO treatment. Using Ingenuity Pathway Analysis software, we identified critical metabolic pathways that were significantly altered by INDO in both intestinal segments including inflammation and also glycolysis, oxidative phosphorylation and free radical scavenging/oxidoreductase activity, which were confirmed by qPCR at the level of individual genes. Taken together, these data revealed that INDO directly exerts multiple detrimental effects on the immature human intestine.

Patent ductus arteriosus in premature neonates

Persistent patency of the ductus arteriosus is a major cause of morbidity and mortality in premature infants. In infants born prior to 28 weeks of gestation, a haemodynamically significant patent ductus arteriosus (PDA) can cause cardiovascular instability, exacerbate respiratory distress syndrome, prolong the need for assisted ventilation and increase the risk of bronchopulmonary dysplasia, intraventricular haemorrhage, renal dysfunction, cerebral palsy and mortality. We review the pathophysiology, clinical features and assessment of haemodynamic significance, and provide a rigorous appraisal of the quality of evidence to support current medical and surgical management of PDA of prematurity. Cyclo-oxygenase inhibitors such as indomethacin and ibuprofen remain the mainstay of medical therapy for PDA, and can be used both for prophylaxis as well as for rescue therapy to achieve PDA closure. Surgical ligation is also effective and is used in infants who do not respond to medical management. Although both medical and surgical treatment have proven efficacy in closing the ductus, both modalities are associated with significant adverse effects. Because the ductus does undergo spontaneous closure in some premature infants, improved and early identification of infants most likely to develop a symptomatic PDA could help in directing treatment to the at-risk infants and allow others to receive expectant management.

Managing the patent ductus arteriosus in the premature neonate: a new look at what we thought we knew

Over recent years, the clinical approach to patency of the ductus arteriosus in the premature neonate has been the subject of intensive reevaluation. What had once been considered inherently obvious is no longer to be taken for granted. In this review we will focus on some of the controversies surrounding various aspects of the pharmacologic treatment regimens for patent ductus arteriosus closure. The pros and cons of prophylactic vs therapeutic indomethacin, of early vs late therapy, of high- vs low-dose indomethacin, of single vs multiple courses of treatment, and of ibuprofen vs indomethacin will be considered. In addition, the possibility that patency of the ductus arteriosus is merely a physiological manifestation of extreme prematurity, and thus does not necessarily need to be therapeutically closed, has become a viable approach in some cases. As such, we will examine echocardiographic and biochemical criteria aimed at determining the clinical and hemodynamic significance of ductal shunting, and thereby of the need to treat. Finally, we speculate on potential therapeutic directions for the future, including individualized treatment regimens and multidrug treatment cocktails for those who fail initial monodrug therapy.

New therapeutic strategies for the treatment of patent ductus arteriosus

In the present manuscript we will focus our attention on the drug choice and its dosage.some studies suggest that the failure of pharmacologic pda closure might be due to the inadequacy of the standard dose regimen, because of large interindividual pharmacokinetics and pharmacodynamic variations in premature infants. we discuss the possibility that the early treatment of pda with ibuprofen doses higher than those actually recommended might increase the closure rate in preterm infants.

New therapeutic strategies for the treatment of patent ductus arteriosus in preterm infants

A high percentage of preterm infants fails to respond to a single course of indomethacin or ibuprofen. Thus, it has been suggested that the actual dose regimens of these drugs could be inadequate because of large interindividual pharmacokinetics variations in premature infants. We tested the hypothesis that a high-dose regimen of ibuprofen was more effective than the current regimen in closing PDA. We demonstrated that a single course of ibuprofen at 20-10-10 mg/kg/day is more effective than a 10-5-5 mg/kg/day course in closing PDA without significant adverse effects. Many other questions regarding the pharmacological treatment of PDA are still debated.

Patent ductus arteriosus in preterm infants

Patent ductus arteriosus (PDA) is a major morbidity in preterm infants, especially in extremely premature infants less than 28 weeks. The clinical signs and symptoms of PDA in preterm infants are non specific and insensitive for making an early diagnosis of significant ductal shunting. Functional echocardiography is emerging as a new valuable bedside tool for early diagnosis of hemodynamically significant ductus, even though there are no universally accepted criteria for grading the hemodynamic significance. Echocardiography has also been used for early targeted treatment of ductus arteriosus, though the long term benefits of such strategy are debatable. The biomarkers like BNP and N terminal pro BNP are currently under research as diagnostic marker of PDA. The primary mode of treatment for PDA is pharmacological closure using cyclo-oxygenase inhibitors with closure rate of 70-80%. Oral ibuprofen is emerging as a better alternative especially in Indian scenario where parenteral preparations of indomethacin are unavailable and side effects are comparatively lesser. Though pharmacological closure of PDA is an established treatment modality, there is still lack of evidence for long term benefits of such therapy as well as there is some evidence for the possible adverse effects like increased ROP and BPD rates, especially if treated prophylactically. Hence, it is prudent to reserve treatment of PDA to infants with clinically significant ductus on the basis of gestation, birth weight, serial echocardiography and clinical status to individualize the decision to treat.

Incidence of and risk factors for neonatal morbidity after active perinatal care: extremely preterm infants study in Sweden (EXPRESS)

AIMS

The aim of this study was to determine the incidence of neonatal morbidity in extremely preterm infants and to identify associated risk factors.

METHODS

Population based study of infants born before 27 gestational weeks and admitted for neonatal intensive care in Sweden during 2004-2007.

RESULTS

Of 638 admitted infants, 141 died. Among these, life support was withdrawn in 55 infants because of anticipation of poor long-term outcome. Of 497 surviving infants, 10% developed severe intraventricular haemorrhage (IVH), 5.7% cystic periventricular leucomalacia (cPVL), 41% septicaemia and 5.8% necrotizing enterocolitis (NEC); 61% had patent ductus arteriosus (PDA) and 34% developed retinopathy of prematurity (ROP) stage > or =3. Eighty-five per cent needed mechanical ventilation and 25% developed severe bronchopulmonary dysplasia (BPD). Forty-seven per cent survived to one year of age without any severe IVH, cPVL, severe ROP, severe BPD or NEC. Tocolysis increased and prolonged mechanical ventilation decreased the chances of survival without these morbidities. Maternal smoking and higher gestational duration were associated with lower risk of severe ROP, whereas PDA and poor growth increased this risk.

CONCLUSION

Half of the infants surviving extremely preterm birth suffered from severe neonatal morbidities. Studies on how to reduce these morbidities and on the long-term health of survivors are warranted.

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.

Neurodevelopmental outcome after COX inhibitor treatment for patent ductus arteriosus

AIM

To compare neurodevelopmental results in very low birth weight (VLBW) infants two years after successful or failed cyclooxygenase inhibitor treatment with either indomethacin or ibuprofen for a haemodynamically significant patent ductus arteriosus (hsPDA).

METHODS

We retrospectively evaluated closure rates and outcome parameters of VLBW infants with hsPDA 89 of whom were treated with indomethacin and 93 with ibuprofen.

RESULTS

Indomethacin and ibuprofen therapy groups did not differ in their baseline clinical profile (median gestational age 26.0 and 26.2wksd) in early (median CRIB 6 and 5, respiratory distress >2 degrees in 36 and 34 infants) and late morbidities (intraventricular hemorrhage >2 degrees in 9 and 10 infants, bronchopulmonary dysplasia in 31 and 27 infants, 80 and 85 survivors), PDA closure rates (63 and 58%) or neurodevelopmental outcome. The therapy failure group (54 infants) was characterized by lower median gestational age (25.0wksd) and higher mortality (17%). No differences were found in the neurodevelopmental outcome of the surviving infants with ligation as compared to the survivors with successful pharmacological closure of the PDA at 24months corrected age.

CONCLUSION

Use of either ibuprofen or indomethacin for closure of a hsPDA did not influence two year neurodevelopmental outcomes in VLBW infants.

Accounting for multiple births in neonatal and perinatal trials: systematic review and case study

OBJECTIVES

To determine the prevalence in the neonatal literature of statistical approaches accounting for the unique clustering patterns of multiple births and to explore the sensitivity of an actual trial to several analytic approaches to multiples.

STUDY DESIGN

A systematic review of recent perinatal trials assessed the prevalence of studies accounting for clustering of multiples. The Nitric Oxide to Prevent Chronic Lung Disease (NO CLD) trial served as a case study of the sensitivity of the outcome to several statistical strategies. We calculated odds ratios using nonclustered (logistic regression) and clustered (generalized estimating equations, multiple outputation) analyses.

RESULTS

In the systematic review, most studies did not describe the random assignment of twins and did not account for clustering. Of those studies that did, exclusion of multiples and generalized estimating equations were the most common strategies. The NO CLD study included 84 infants with a sibling enrolled in the study. Multiples were more likely than singletons to be white and were born to older mothers (P < .01). Analyses that accounted for clustering were statistically significant; analyses assuming independence were not.

CONCLUSIONS

The statistical approach to multiples can influence the odds ratio and width of confidence intervals, thereby affecting the interpretation of a study outcome. A minority of perinatal studies address this issue.

Role of prostaglandin E and its receptors in the process of ductus arteriosus maturation and functional closure in the rabbit

1. Patent ductus arteriosus (PDA) is a common congenital heart defect in premature infants. The present study was designed to determine the role of the prostaglandin (PG) E(2) pathway in the process of ductus arteriosus (DA) maturation and functional closure. 2. Changes in PGE(2) pathway-related enzymes and receptors in DA in preterm and term rabbits were examined at both the mRNA and protein levels. In addition, responses of DA rings to Po(2) and PGE(2) were determined. 3. Circulating PGE(2) levels remained high until 2 h after birth. High levels of the EP(4) receptor were found in preterm DA. These tissues were sensitive to PGE(2), which caused vessel dilation, but were insensitive to increased Po(2). In contrast, DA tissues from term rabbits exhibited an immediate contractile response to increased Po(2) and PGE(2) treatment resulted in vasoconstriction, which was associated with increased EP(3) and decreased EP(4) receptor expression in term DA. 4. In conclusion, the preterm PDA is maintained by high levels of PGE(2), which mainly binds to the EP(4) receptor under conditions of hypoxia. In contrast, in the term DA, in which levels of the EP(3) receptor are higher than in preterm DA, exposure to PGE(2) resulted in vasoconstriction under normoxic conditions. These findings suggest that blocking the EP(4) receptor may represent a more selective treatment for the preterm PDA, whereas activating the EP(3) receptor may be more suitable for the treatment of the term PDA.

A second course of ibuprofen is effective in the closure of a clinically significant PDA in ELBW infants

OBJECTIVES

There are few published data on the efficacy of ibuprofen in the most immature infants and no data on repeated courses. Our objectives were to describe PDA closure rates in a population of infants <1000 g birth weight after repeated courses of ibuprofen, to examine the effect of gestation, and to document plasma markers of renal function and platelet counts.

METHODS

This was a single center observational study. We collected data on infants weighing <1000 g at birth who were treated with ibuprofen for a clinically significant PDA. A successful outcome was defined as resolution of clinical symptoms such that no additional treatment was required. Serum biochemistry and hematology data were analyzed and compared with controls.

RESULTS

We identified 160 infants with a mean +/- SD birth weight of 757 +/- 127 g and gestation of 25.6 +/- 1.4 weeks. Seventy infants closed their PDA after a single course of ibuprofen (45%) and 32/80 (40%) following a second. Infants of <26 weeks' gestation (n = 83) were less likely to respond after both the first (27.7% vs 63.6%; P < .001) and second (30.9% vs 60.0%; P = .026) courses. The postnatal decrease in plasma creatinine was delayed by ibuprofen treatment, while platelet counts and other plasma markers were unaffected.

CONCLUSIONS

In our study population, PDA closure was gestation dependant, with a cumulative closure rate of 65%. A similar proportion of infants closed their PDA following the first and second courses regardless of gestation. These data suggest that a second course of ibuprofen may be effective in closing a PDA in even the most preterm infant.

Recent Publications on Medications and Pharmacy

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