Prophylactic indomethacin: factors determining permanent ductus arteriosus closure

Patent Ductus Arteriosus Response to Treatment by Course and Associations with Perinatal and Clinical Factors

OBJECTIVE

 The objective of this study is to examine patent ductus arteriosus (PDA) response by treatment course and investigate associations with postmenstrual age (PMA), chronological age (CA), gestational age (GA), antenatal steroid exposure (ANS), birthweight (BW), weight at treatment initiation (WT), and PDA/left pulmonary artery (LPA) ratio.

STUDY DESIGN

 This is a single-center retrospective cohort study of preterm infants less than 37 weeks' GA born January 1, 2016 to December 31, 2018 who received acetaminophen and/or indomethacin for PDA treatment. Cox proportional hazards regression models were used to determine whether factors of interest were associated with PDA response to medical treatment.

RESULTS

 In total, 289 treatment courses were administered to 132 infants. Thirty-one (23%) infants experienced treatment-associated PDA closure. Ninety-four (71%) infants had evidence of PDA constriction following any treatment course. Ultimately, 84 (64%) infants experienced definitive PDA closure. For each 7-day increase in CA at the time of treatment initiation, the PDA was 59% less likely to close (p = 0.04) and 42% less likely to respond (i.e., constrict or close) to treatment (p < 0.01). PDA/LPA ratio was associated with treatment-associated PDA closure (p = 0.01). For every 0.1 increase in the PDA/LPA ratio, the PDA was 19% less likely to close in response to treatment.

CONCLUSION

 In this cohort, PDA closure is independent of PMA, GA, ANS, BW, and WT; however, CA at treatment initiation predicted both treatment-associated PDA closure and PDA response (i.e., constriction or closure), and PDA/LPA ratio was associated with treatment-associated closure. Most infants experienced PDA constriction rather than closure, despite receiving up to four treatment courses.

KEY POINTS

· Detailed PDA responses for up to four treatment courses provide a novel perspective.. · Chronological age at the start of treatment predicted treatment-associated PDA closure and response.. · For each 7-day increase in chronological age, the PDA was 59% less likely to close..

Prophylactic Intravenous Acetaminophen in Extremely Premature Infants: Minimum Effective Dose Research by Bayesian Approach

BACKGROUND

Patent ductus arteriosus (PDA) in preterm infants is associated with increased morbidities and mortality. Prophylactic treatment with cyclooxygenase inhibitors, as indomethacin or ibuprofen, failed to demonstrate significant clinical benefits. Acetaminophen may represent an alternative treatment option.

OBJECTIVE

This study evaluated the minimum effective dose of prophylactic acetaminophen to close the ductus and assessed the safety and tolerability profile in extremely preterm infants at 23-26 weeks of gestation.

METHODS

A dose finding trial with Bayesian continual reassessment method was performed in a multicenter study with premature infants hospitalized in neonatal intensive care unit. Infants of 23-26 weeks of gestation and post-natal age ≤ 12 h were enrolled. Four intravenous acetaminophen dose levels were predefined. The primary outcome was the ductus arteriosus closing at two consecutive echocardiographies or at day 7. The main secondary objectives included the safety of acetaminophen on hemodynamics and biological hepatic function.

RESULTS

A total of 29 patients were analyzed sequentially for the primary analysis with 20 infants assigned to the first dose level followed by 9 infants to the second dose level. No further dose level increase was necessary. The posterior probabilities of success, estimated from the Bayesian logistic model, were 46.1% [95% probability interval (PI), 24.9-63.9] and 67.6% (95% PI, 51.5-77.9) for dose level 1 and 2, respectively. A closing or closed pattern was observed among 19 patients at the end of treatment [65.5% (95% confidence interval (CI), 45.7-82.0)]. No change in alanine aminotransferase values was observed during treatment. A significant decrease in aspartate aminotransferase values was observed with postnatal age. No change in systolic and diastolic blood pressures was observed during treatment.

CONCLUSIONS

Minimum effective dose to close the ductus was 25 mg/kg loading dose then 10 mg/kg/6 h for 5 days in extremely preterm infants. Acetaminophen was well tolerated in this study following these doses.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04459117.

Use of Prophylactic Indomethacin in Preterm Infants: A Systematic Review and Meta-Analysis

BACKGROUND

Prophylactic indomethacin has been widely used as an effective intervention for reducing mortalities and morbidities in preterm infants including the cardiopulmonary and neurodevelopmental morbidities such as intraventricular hemorrhage (IVH), but many studies have reported contradictory outcomes regarding its significance. Therefore, we aim to systematically review and meta-analyze the data of prophylactic indomethacin on preterm infants.

METHODS

Our systematic search included the following databases: Pubmed, Google Scholar, Scopus, Web of Science, The New York Academy of Medicine (NYAM), Virtual health library (VHL), and the System for Information on Grey Literature in Europe (SIGLE) to include studies that assessed the use of prophylactic indomethacin in preterm infants until 12 August 2021.

RESULTS

The final list of our included studies is comprised of 23 randomized trials and cohort studies. Among all the studies outcomes, significant favorable outcome was lowering the rate of PDA, surgical PDA ligation (P < 0.001) and severe IVH (P = 0.008) while no significance was recorded with BPD, pulmonary hemorrhage, intraventricular hemorrhage, necrotizing enterocolitis, intestinal perforation, mortality, and length of hospital stay.

CONCLUSION

Since the meta-analysis results regarding effectiveness of prophylactic indomethacin varied based on the study design particularly with regard to outcomes such as surgical PDA ligation and severe IVH, this warrants the need for more evidence regarding the effectiveness of prophylactic indomethacin in very low birth weight infants.

Spontaneous Closure of the Ductus Arteriosus in Preterm Infants: A Systematic Review

The optimal management strategy for patent ductus arteriosus in preterm infants remains a topic of debate. Available evidence for a treatment strategy might be biased by the delayed spontaneous closure of the ductus arteriosus in preterm infants, which appears to depend on patient characteristics. We performed a systematic review of all literature on PDA studies to collect patient characteristics and reported numbers of patients with a ductus arteriosus and spontaneous closure. Spontaneous closure rates showed a high variability but were lowest in studies that only included preterm infants with gestational ages below 28 weeks or birth weights below 1,000 g (34% on day 4; 41% on day 7) compared to studies that also included infants with higher gestational ages or higher birth weights (up to 55% on day 3 and 78% on day 7). The probability of spontaneous closure of the ductus arteriosus keeps increasing until at least 1 week after birth which favors delayed treatment of only those infants that do not show spontaneous closure. Better prediction of the spontaneous closure of the ductus arteriosus in the individual newborn is a key factor to find the optimal management strategy for PDA in preterm infants.

Standard-dose gentamicin does not increase risk of patent ductus arteriosus

BACKGROUND

Rates of patent ductus arteriosus (PDA) and infection are high in preterm infants. Preterm infants with infection are more likely to develop symptomatic PDA, a potentially fatal disease. Clinically, gentamicin is widely used for early-onset infection in neonates including preterm infants. A recent study demonstrated that standard-dose gentamicin itself, not infection, increased risk of PDA in mice, suggesting that gentamicin should be avoided in neonates with a risk of PDA. This claim has been insufficiently investigated in subsequent in-vivo experiments. We reevaluated the in-vivo effect of standard-dose gentamicin on patency of the rat ductus arteriosus (DA).

METHODS

1) To evaluate the effect of gentamicin on DA patency duration, gentamicin was intraperitoneally injected immediately after birth. 2) To evaluate the effect of gentamicin on DA reopening, gentamicin was intraperitoneally injected 30 min after birth. In both scenarios, 30 min after gentamicin administration, rapid whole-body freezing was performed and the inner diameter of the DA was measured.

RESULTS

Standard-dose gentamicin (5 μg/g) did not prolong patency of the DA or increase the likelihood of DA reopening in rat neonates. High-dose gentamicin (100 μg/g), however, significantly prolonged patency of the DA and was associated with DA reopening in rat neonates, although the dilative effect did not reach statistical significance.

CONCLUSION

Standard-dose gentamicin does not increase the risk of PDA in rat neonates. This study suggests that standard-dose gentamicin can be used to treat infection in neonates without increasing PDA morbidity.

Pre-symptomatic targeted treatment of patent ductus arteriosus in preterm newborns: A systematic review and meta-analysis

BACKGROUND

A clinically significant patent ductus arteriosus (PDA) is associated with significant morbidity and mortality in premature newborns. Symptomatic PDAs are often treated with prostaglandin synthesis inhibitors (PSI), but controversy remains if PSIs should also be used to manage early, asymptomatic PDAs.

OBJECTIVE

To systematically identify, critically appraise, and evaluate the efficacy and safety of pharmacological management of pre-symptomatic PDA in preterm newborns after confirmed patency by echocardiography.

STUDY DESIGN

Systematic review and meta-analysis.

SEARCH METHODS

We searched MEDLINE (Ovid), EMBASE (Ovid), Cochrane Central Register of Controlled Trials (Wiley), from date of inception to February 2017. Supplemental searching was performed in Scopus and Web of Science to identify additional relevant citations. We also searched conference proceedings, reference lists of relevant articles and the WHO International Clinical Trials Registry Platform (ICTRP).

SELECTION CRITERIA

We included only randomized controlled trials (RCTs) that compared the use of indomethacin or ibuprofen to placebo for treatment of pre-symptomatic PDA in preterm newborns (<32 weeks gestational age and <1500gms).

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected trials, assessed risk of bias and extracted trial-level data. Outcomes are reported as risk ratios from random-effects models. Absolute risk reduction (ARR) is additionally reported for significant outcomes.We included seven trials (466 newborns). Targeted medical treatment did not significantly reduce mortality rates (RR 0.85, 95% CI 0.50 to 1.43; ARR -2.38%, 95% CI -8.04% to 3.29%; I2 0% 6 studies; 442 newborns), but it did significantly reduce the overall incidence of developing symptomatic PDA (RR 0.39, 95% CI 0.21 to 0.73; ARR -34.3%, 95% CI -50.8% to -17.8%; I2 0%; 3 studies; 97 newborns) compared to placebo. Other efficacy or safety outcomes were not significantly different.

CONCLUSIONS

Targeted medical treatment of pre-symptomatic PDA decreases the incidence of developing symptomatic PDA, but not neonatal mortality. Further studies are essential to confirm these results.

Tratamiento farmacológico del conducto arterioso permeable en recién nacidos prematuros

Introducción. Por lo general, el manejo farmacológico del conducto arterioso permeable (CAP) comprende inhibidores no selectivos de la enzima ciclooxigenasa, en especial indometacina e ibuprofeno. En años recientes también se ha sugerido al acetaminofén como alternativa terapéutica.Objetivo. Realizar una revisión narrativa de la literatura acerca del manejo farmacológico del CAP.Materiales y métodos. Se realizó una búsqueda estructurada de la literatura en las bases de datos ProQuest, EBSCO, ScienceDirect, PubMed, LILACS, Embase, Trip Database, SciELO y Cochrane Library con los términos “Ductus Arteriosus, patent AND therapeutics”; “Ductus Arteriosus, patent AND indometacin”; “Ductus Arteriosus, Patent AND ibuprofen”, y “Ductus Arteriosus, patent AND acetaminophen”. La búsqueda se hizo en inglés con sus equivalentes en español.Resultados. Se encontraron 69 artículos con información relevante para llevar a cabo la presente revisión.Conclusiones. En neonatos prematuros, la base del tratamiento farmacológico del CAP continúa siendo los inhibidores no selectivos de la ciclooxigenasa, indometacina e ibuprofeno, ambos con perfiles similares de seguridad y eficacia. La evidencia disponible sugiere que el acetaminofén podría constituir una alternativa útil para el manejo, pero resulta insuficiente para realizar recomendaciones definitivas respecto a la eficacia y seguridad de este medicamento.

Efficacy of pharmacologic closure of patent ductus arteriosus in small-for-gestational-age extremely preterm infants

BACKGROUND

Optimal management of the patent ductus arteriosus (PDA) in preterm infants remains controversial. Therefore, studies identifying infants who are most likely to benefit from PDA treatment are needed.

AIM

We sought to examine if significant intrauterine growth restriction, defined by birth weight z-score, reduces the efficacy of PDA closure with indomethacin or ibuprofen and thereby increases the need for surgical closure of PDA after pharmacologic treatment.

STUDY DESIGN, SUBJECTS, AND OUTCOME MEASURES

We studied infants 23-28weeks' gestation born 2006-2013 at NICHD Neonatal Research Network centers. We examined the responses to PDA treatment with indomethacin and/or ibuprofen and whether the PDA was subsequently closed surgically. Logistic regression generated adjusted odds ratios (ORs) for the associations between the z-score groups (<-2, -2 to -0.5, and >-0.5) and PDA surgery following pharmacologic treatment.

RESULTS

5606 infants were diagnosed with PDA; 3587 (64.0%) received indomethacin or ibuprofen or both, and 909 (25.3%) underwent PDA surgery. Mothers of infants with PDA non-closure were less likely to have hypertension (19% vs. 28%). Infants with non-closure were more likely to be female (53% vs. 49%), have lower gestational age and birth weight and to develop sepsis (42% vs. 31%). Compared to infants with z-score>-0.5, PDA surgery was increased among infants with z-score -2 to -0.5 (OR=1.23; 95% CI 1.02-1.47) but not among infants with z-score<-2.

CONCLUSION

Infants with birth weight z-score -2 to -0.5 are more likely than normally grown infants to require PDA surgery following pharmacologic treatment.

Outcomes following indomethacin prophylaxis in extremely preterm infants in an all-referral NICU

OBJECTIVE

We examined data from a contemporary cohort of extreme prematurity (EP) infants admitted to an all-referral Children's Hospital neonatal intensive care unit (NICU) to determine whether prophylactic indomethacin (PI) may continue to benefit these patients.

STUDY DESIGN

An observational study utilizing the small baby ICU data registry that was queried for all EP infants admitted between 2005 and 2014 with documentation of PI use (671 total EP infants; 141 (21%) did not receive PI (control); 530 (79%) received PI (PI). This cohort of EP infants was born at outside hospitals and transferred to our level IV NICU with a mean age on admission of 13 days, well after the PI would have been administered.

RESULTS

No difference existed between the control and PI groups in gestational age, birth weight, severity of illness, other in-hospital outcomes or developmental delay. PI infants had a significantly lower mortality rate (P=0.0004), lower relative risk (RR) for mortality 0.52 (95% confidence interval (CI) 0.37 to 0.73, P=0.0001) and lower RR of developing the combined outcome of death or bronchopulmonary dysplasia (RR 0.91, 95% CI 0.85 to 0.98, P=0.012) when compared with the control group. Notably, there was no significant effect of PI on incidence of severe intraventricular hemorrhage or patent ductus arteriosus ligation.

CONCLUSION

PI administration was associated with improved survival in EP infants referred to a level IV Children's Hospital NICU.

Factors associated with non-response to second course indomethacin for PDA treatment in preterm neonates

BACKGROUND

Failure of first course of indomethacin (FCI) for patent ductus arteriosus (PDA) treatment in preterm neonates often prompts clinicians to consider a second course (SCI).

OBJECTIVE

To identify factors including baseline characteristics and response to FCI that are associated with non-response to SCI for PDA treatment in preterm neonates.

METHODS

In this retrospective observational study, neonates ≤32 weeks admitted to a tertiary NICU over 5 years who received two indomethacin courses for PDA treatment were reviewed. Only neonates with echocardiograms (ECHO) immediately before and after receipt of each indomethacin course were included. Primary outcome was non-response to SCI. Baseline characteristics and response to FCI were compared between responders and non-responders of SCI.

RESULTS

Of the 98 neonates enrolled, 47 (48%) had non-response to SCI. Of them, 27 patients (57%) had prior non-response to FCI, while of the 51 neonates who responded to SCI, 24 neonates (47%) had prior non-response to FCI. The adjusted risk of non-response to SCI in patients who had non-response to FCI was 37% higher (relative risk = 1.37, 95%CI: 0.87-1.80; p = .07) compared to those who had response to FCI. Multivariable analysis showed that increasing gestational age (AOR: 1.6, 95%CI: 1.1-2.3, p = .03) was associated with a higher odds of non-response to SCI while the odds of non-response to SCI increased by 90% in patients with non-response to FCI (AOR: 1.9, 95%CI: 0.8-4.5; p = .15) compared to those with success of FCI, although no statistical significance was observed.

CONCLUSIONS

Advanced gestational age was the predictor of non-response to SCI in preterm neonates.

Intravenous paracetamol for PDA closure in the preterm: a single-center experience

Increasing recent evidence favors paracetamol use for patent ductus arteriosus (PDA) closure in preterms. Our study aims were (1) to assess efficacy and safety of intravenous (i.v.) paracetamol for PDA closure in a 23-32-week preterm population, as "first-line" (when traditional ibuprofen treatment was contraindicated) or "rescue" treatment (after ibuprofen failed), and (2) to identify predictors of PDA closure. The cumulative efficacy of consecutive cycles of i.v. paracetamol on PDA closure was confirmed after both "first-line" and "rescue" treatment, the overall PDA closure rates being, respectively, 56.7 and 61.1 % (p = 0.7624) after two cycles and 63.3 and 77.8 % (p = 0.2959) after three cycles. No toxicity was apparent after either "first-line" or "rescue" i.v. paracetamol treatment. On multivariate analysis, gestational age (GA) emerged as an independent predictor of PDA closure in the "first-line" i.v. paracetamol treatment group, while clinical risk index for babies (CRIB) score (a patient risk index based on birth weight, GA at birth, sex, patient's temperature on admission, and maximum base excess in first 12 h of life) was an independent predictor of PDA closure failure in the "rescue" group.

CONCLUSION

I.V. paracetamol proved effective in our study population. Randomized control trials (RCTs) are warranted to further investigate the efficacy and safety of i.v. paracetamol for PDA closure in preterms.

WHAT IS KNOWN

• Oral paracetamol has been judged as effective as oral ibuprofen for PDA closure in the preterm. • To date, only a handful of non-randomized studies exist to support the effectiveness of i.v. paracetamol in PDA closure. What is New: • Our observations confirm the clinical efficacy of i.v. paracetamol for PDA closure in a very low birth weight (VLBW)/extremely low birth weight (ELBW) preterm population. • Gestational age and CRIB score emerge as independent predictors of PDA closure.

Neurodevelopmental Outcome at 2 Years of Age according to Patent Ductus Arteriosus Management in Very Preterm Infants

BACKGROUND

Patent ductus arteriosus (PDA) is a condition frequently found in very preterm infants, and its treatment remains a subject of debate. Furthermore, there are only a few studies available that have examined the impact of these treatments on the neurological outcome of the patient.

OBJECTIVE

To evaluate the neurodevelopmental outcome of PDA treatment on preterm infants born between 24+0 and 28+6 weeks of gestation.

METHODS

We conducted an observational multicentric cohort study (LIFT Cohort). We compared three groups of patients according to their PDA treatment strategy: medical treatment with ibuprofen, surgical ligation, and no treatment. The neurodevelopmental outcome was assessed with a physical examination and cognitive function evaluation at 2 years of age. A propensity score was used to reduce bias in the analysis.

RESULTS

Between 2003 and 2011, 857 infants (91.3%) were evaluated at 2 years of corrected age and included in the analysis: 248 received ibuprofen treatment (29%), 104 had PDA surgical ligation (12%), and 505 did not receive any PDA treatment (59%). Surgical ligation of PDA was significantly associated with neurodevelopmental impairment at 2 years of age (adjusted odds ratio = 2.2; 95% confidence interval: 1.4-3.4).

CONCLUSION

We found an association between PDA surgical ligation and a nonoptimal neurodevelopmental outcome at 2 years of age for preterm infants born before 29 weeks of gestation. These results suggest that if surgical ligation is unavoidable, particular attention should be given to the patient's neurodevelopmental follow-up.

Potential Unintended Consequences of a Conservative Management Strategy for Patent Ductus Arteriosus

BACKGROUND

A recent review supports a strategy of deferring treatment of patent ductus arteriosus (PDA) in the preterm neonate until at least the second week after birth. In light of previous suggestion that later initiation of treatment may be less efficacious for closing PDAs it is reasonable to question if delayed treatment may be less effective.

DESIGN

We conducted a single center retrospective review of a neonatal intensive care unit database of infants ≤37 weeks gestation with the diagnosis of PDA and treated with indomethacin from 1999 to 2007. We determined gestational age (GA), timing of indomethacin initiation, and status of the PDA at hospital discharge. Treatment failure was defined as neonates requiring further intervention to close their PDA or those who died without echo-proven PDA closure.

RESULTS

Of the 341 infants meeting the study criteria, 77 (23%) had defined treatment failure. The failure group had a younger median GA of 25 weeks (interquartile range [IQR], 24-26) vs. 28 weeks (IQR, 26-30) for the successful group (P < .0001). The failure group had a median treatment initiation on day of life (DOL) 4 (IQR, 1-8) compared with DOL 3 (IQR, 1-6) for those in the successful group (P = .15). Taken as a whole, infants treated after DOL 5 were significantly more likely to have treatment failure (30.1% vs. 19.3% for those treated DOL 1-5, P = .03).

CONCLUSIONS

Our study confirms that younger GA at birth is correlated with increased likelihood of failed PDA closure. We also show a trend indicating that later initiation of treatment may decrease the chances of successfully closing a PDA. Future examination of PDA management should consider the potential unintended consequences that may accompany a delayed treatment strategy.

Natural evolution of patent ductus arteriosus in the extremely preterm infant

OBJECTIVE

The persistence of the patent ductus arteriosus (PDA) is frequently encountered in very preterm infants. Neither preventive nor curative treatments of PDA have been shown to improve the outcome of these infants. Since no consensus on optimal treatment of PDA is established, we evaluated the rate of spontaneous PDA closure in infants born before 28 weeks of gestation.

PATIENTS AND METHODS

We studied a retrospective cohort of 103 infants (gestational age 24-27 weeks) admitted to our neonatal intensive care unit from 1 June 2008 to 31 July 2010. Maternal and neonatal characteristics were collected. The PDA was defined by the persistence of ductal patency after 72 h and was followed up by regular echocardiography.

RESULTS

Twelve infants died within the first 72 h and were excluded from the analysis. Among 91 infants analysed, 8 (9%) closed their ductus arteriosus before 72 h and the ductus could not be determined patent in 13. Of the 70 infants with a PDA still persistent, one underwent surgical ligation and echocardiography showed spontaneous closure in 51 (73%) of them. In the remaining 18 infants, the date of PDA closure could not be determined either because of their death (n=11) or due to discharge (n=7). Overall, a spontaneous closure of the ductus arteriosus was observed in 59 of the 91 infants.

CONCLUSIONS

We have to question whether exposure to the risks of therapeutic interventions targeted for ductal closure is warranted since a PDA closes spontaneously in at least 73% of infants born before 28 weeks.

Indomethacin administered early in the postnatal period results in reduced glomerular number in the adult rat

Indomethacin and ibuprofen are administered to close a patent ductus arteriosus (PDA) during active glomerulogenesis. Light and electron microscopic glomerular changes with no change in glomerular number were seen following indomethacin and ibuprofen treatment during glomerulogenesis at 14 days after birth in a neonatal rat model. This present study aimed to determine whether longstanding renal structural changes are present at 30 days and 6 mo (equivalent to human adulthood). Rat pups were administered indomethacin or ibuprofen antenatally on days 18-20 (0.5 mg·kg(-1)·dose(-1) indomethacin; 10 mg·kg(-1)·dose(-1) ibuprofen) or postnatally intraperitoneally from day 1 to 3 or day 1 to 5 (0.2 mg·kg(-1)·dose(-1) indomethacin; 10 mg·kg(-1)·dose(-1) ibuprofen). Control groups received no treatment or normal saline intraperitoneally. Pups were killed at 30 days of age and 6 mo of age. Tissue blocks from right kidneys were prepared for light and electron microscopic examination, while total glomerular number was determined in left kidneys using unbiased stereology. Eight pups were included in each group from 14 maternal rats. At 30 days and 6 mo, there were persistent electron microscopy abnormalities of the glomerular basement membrane in those receiving postnatal indomethacin and ibuprofen. There were no significant light microscopy findings at 30 days or 6 mo. At 6 mo, there were significantly fewer glomeruli in those receiving postnatal indomethacin but not ibuprofen (P = 0.003). In conclusion, indomethacin administered during glomerulogenesis appears to reduce the number of glomeruli in adulthood. Alternative options for closing a PDA should be considered including ibuprofen as well as emerging therapies such as paracetamol.

Managing the patent ductus arteriosus: current treatment options

Optimal management of the patent ductus arteriosus (PDA) in the premature infant remains controversial. Despite considerable historical and physiological data indicating that a persistent PDA may be harmful, robust evidence of long-term benefits or harms from treatment is lacking. This has been equated to a lack of benefit but is also a reflection of the fact that most clinical trials were designed to assess the effects of short-term (2-8 days) rather than prolonged exposure to a PDA. No clinical trials have been designed to assess the effects of prolonged exposure of persistent PDA on morbidity and mortality of very premature infants in the era of antenatal corticosteroids, surfactant and non-invasive respiratory support. Further research is required, but new insights and novel therapies are evolving, which will allow greater individual patient assessment, understanding of risk and optimisation of treatment. In this paper, we review the current literature, evidence for treatment options, including a non-interventional approach, and research directions for infants <28 weeks' gestational age.

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).

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.

Surgical versus medical treatment with cyclooxygenase inhibitors for symptomatic patent ductus arteriosus in preterm infants

BACKGROUND

A patent ductus arteriosus (PDA) with significant left to right shunt increases morbidity and mortality in preterm infants. Early closure of the ductus arteriosus may be achieved pharmacologically or by surgery. The preferred initial treatment of a symptomatic PDA, surgical ligation or treatment with indomethacin, is not clear.

OBJECTIVES

To compare the effect of surgical ligation of PDA versus medical treatment with cyclooxygenase inhibitors (indomethacin, ibuprofen or mefenamic acid), each used as the initial treatment, on neonatal mortality in preterm infants with a symptomatic PDA.

SEARCH METHODS

For this update we searched The Cochrane Library 2012, Issue 2, MEDLINE, EMBASE, CINAHL, Clinicaltrials.gov, Controlled-trials.com, Proceedings of the Annual Meetings of the Pediatric Academic Societies (2000 to 2011) (Abstracts2View(TM)) and Web of Science on 8 February 2012.

SELECTION CRITERIA

Randomised or quasi-randomised trials in preterm or low birth weight neonates with symptomatic PDA and comparing surgical ligation with medical treatment with cyclooxygenase inhibitors, each used as the initial treatment for closure of PDA.

DATA COLLECTION AND ANALYSIS

The authors independently assessed methodological quality and extracted data for the included trial. We used RevMan 5.1 for analyses of the data.

MAIN RESULTS

One study reporting on 154 neonates was found eligible. No significant difference between surgical closure and indomethacin treatment was found for in-hospital mortality, chronic lung disease, necrotising enterocolitis, sepsis, creatinine level or intraventricular haemorrhage. There was a significant increase in the surgical group in the incidence of pneumothorax (risk ratio (RR) 2.68; 95% confidence interval (CI) 1.45 to 4.93; risk difference (RD) 0.25; 95% CI 0.11 to 0.38; number needed to treat to harm (NNTH) 4 (95% CI 3 to 9)) and retinopathy of prematurity stage III and IV (RR 3.80; 95% CI 1.12 to 12.93; RD 0.11; 95% CI 0.02 to 0.20; NNTH 9 (95% CI 5 to 50)) compared to the indomethacin group. There was a statistically significant decrease in failure of ductal closure rate in the surgical group as compared to the indomethacin group (RR 0.04; 95% CI 0.01 to 0.27; RD -0.32; 95% CI -0.43 to -0.21, number needed to treat to benefit (NNTB) 3 (95% CI 2 to 4)). No new trials were identified for inclusion in the 2012 update.

AUTHORS' CONCLUSIONS

There are insufficient data to conclude whether surgical ligation or medical treatment with indomethacin is preferred as the initial treatment for symptomatic PDA in preterm infants.

Early echocardiographic prediction of ductal closure in neonates ≤ 30 weeks gestation

OBJECTIVE

To determine the accuracy of the patent ductus arteriosus:left pulmonary artery ratio (PDA:LPA) on echocardiogram (ECHO) at 3-day postnatal in predicting spontaneous PDA closure in neonates ≤ 30 weeks gestational age (GA).

STUDY DESIGN

ECHOs were performed at 72 h to characterize PDA size as closed-to-small (PDA:LPA <0.5) or moderate-to-large (PDA:LPA ≥ 0.5) and at 10 days to determine spontaneous closure (defined as closed-to-small in the absence of medical and/or surgical treatment). Caretakers were blinded to results; treatment was based on standard care. Neonates were prospectively enrolled and stratified: <27 weeks (n=31) and 27 to 30 weeks (n=65).

RESULT

Neonates <27 weeks with closed-to-small PDAs had 60% spontaneous closure vs 9% when moderate-to-large (positive predictive value (PPV) 60%, negative predictive value (NPV) 91%). Neonates 27 to 30 weeks had 95% spontaneous closure vs 27%, respectively (PPV 95%, NPV 73%). Inter-observer variability for the initial ECHO was 0.84.

CONCLUSION

PDA size defined by PDA:LPA at 3 days postnatal in combination with GA predicts spontaneous PDA closure.

A high ductal flow velocity is associated with successful pharmacological closure of patent ductus arteriosus in infants 22-27 weeks gestational age

Objective. To identify factors affecting closure of patent ductus arteriosus (PDA) in newborn infants born at 22–27 weeks gestational age (GA) during pharmacological treatment with cyclooxygenase inhibitors. Method. Infants born at 22–27 weeks of GA between January 2006 and December 2009 who had been treated pharmacologically for PDA were identified retrospectively. Medical records were assessed for clinical, ventilatory, and outcome parameters. Echocardiographic examinations during treatment were reviewed. Results. Fifty-six infants were included in the study. Overall success rate of ductal closure with pharmacological treatment was 52%. Infants whose PDA was successfully closed had a higher GA (25 + 4 weeks versus 24 + 3 weeks; P = 0.047), and a higher pretreatment left to right maximal ductal flow velocity (1.6 m/s versus 1.1 m/s; P = 0.023). Correcting for GA, preeclampsia, antenatal steroids, and age at start of treatment, a higher maximal ductal flow velocity was still associated with successful ductal closure (OR 3.04; P = 0.049). Conclusion. Maximal ductal flow velocity was independently associated with success of PDA treatment.

Evidence-based use of indomethacin and ibuprofen in the neonatal intensive care unit

Indomethacin and ibuprofen are potent inhibitors of prostaglandin synthesis. Neonates have been exposed to these compounds for more than 3 decades. Indomethacin is commonly used to prevent intraventricular hemorrhage (IVH), and both drugs are prescribed for the treatment or prevention of patent ductus arteriosus (PDA). This review examines the basis for indomethacin and ibuprofen use in the neonatal intensive care population. Despite the call for restrained use of each drug, the most immature infants are likely to need pharmacologic approaches to reduce high-grade IVH, avoid the need for PDA ligation, and preserve the opportunity for an optimal outcome.

Determinants of surgical repair of patent ductus arteriosus in low-birth-weight infants

PURPOSE

To identify risk factors related to the failure of indomethacin therapy and the need for surgical repair in patent ductus arteriosus (PDA) in extremely low-birth-weight (<1000 g) infants (ELBWI).

METHODS

Study subjects were 36 ELBWI with PDA born at a single tertiary perinatal center. They were classified into those who required surgery due to failure of indomethacin treatment (surgical group, n = 21) and those with effective indomethacin treatment (non-surgical group, n = 15). The odds ratios (ORs) and 95% confidence intervals (95% CIs) for the relationship between selected risk factors and surgical treatment of PDA were calculated.

RESULTS

Gestational age of <28 weeks and diameter of PDA of 2 mm or more were independent and significant determinants of the need for surgical repair of PDA (adjusted ORs [95% CIs] = 9.91 [1.16-84.48] and 24.80 [2.72-225.74], respectively). The need for surgical repair of PDA did not correlate with sex, birth weight, 1-min Apgar score, left atrium diameter/aortic diameter (LA/Ao), left ventricular internal dimension at end-diastole, prophylaxes with indomethacin, and total dosage of indomethacin.

CONCLUSIONS

Gestational age at birth of <28 weeks and diameter of PDA of 2 mm or more are determinants of failure of indomethacin treatment for PDA and the need for surgical repair.

Are cytochrome P450 CYP2C8 and CYP2C9 polymorphisms associated with ibuprofen response in very preterm infants?

BACKGROUND

Patent ductus arteriosus (PDA) in extremely preterm infants remains a challenging condition with conflicting treatment strategies. Ibuprofen is currently used to treat PDA with ductal closure failure rate up to 40%. We test the hypothesis that cytochrome P450 CYP2C8/2C9 polymorphisms may predict ibuprofen response.

METHODOLOGY/PRINCIPAL FINDINGS

We studied extremely preterm neonates with haemodynamically significant PDA and treated with ibuprofen. One or two variant CYP2C8 and/or 2C9 alleles were found in 17% of the population, most of them were from Caucasian ethnicity (67-74%). Response to ibuprofen and clinical course of infants carrying variants CYP2C8 and CYP2C9 were similar. Comparing infants with wild type or variant CYP2C8 and CYP2C9 genotypes, response rate to ibuprofen was significantly higher in wild type than in mutated carriers in univariate analysis (73% versus 52%, p = 0.04). Comparing responders (ductus closure; n = 75) and non-responders (surgical ligation; n = 36), the only two factors significantly associated with the response to ibuprofen using multivariate analysis were higher gestational age and non Caucasian ethnicity but not CYP2C polymorphism.

CONCLUSIONS

CYP2C polymorphism was not associated with PDA response to ibuprofen and this factor appears not appropriate to optimize the ductal closure rate by modulating ibuprofen dosing strategy. This study points out the role for ethnicity in the interindividual variability of response to ibuprofen in extremely preterm infants.

Echocardiography predicts closure of patent ductus arteriosus in response to ibuprofen in infants less than 28 week gestational age

BACKGROUND

Patent ductus arteriosus (PDA) is a frequent problem in preterm infants, and its incidence is inversely correlated with gestational age. The efficacy of medical treatment decreases with decreasing gestational age (GA), and failure rates as well as ductus ligation rates of 40% have been reported in <28 week GA newborns. The aim of this study was to determine whether echocardiographic parameters can predict response to ibuprofen treatment of PDA.

STUDY DESIGN

In a longitudinal study, 29 infants born <28 week GA were screened for a significant PDA (left atrial to aortic root ratio>1.4, anterior cerebral artery resistance index>0.8, and oxygen requirement>35%) at 24-72 h of life and, if a PDA was found, treated with 10-5-5mg/kg ibuprofen intravenously every 24h. Ductal parameters were monitored by serial echocardiography. Infant neurodevelopmental outcomes were assessed at 24 month corrected age.

RESULTS

All 15 infants with significant PDA responded to the ibuprofen loading dose indicated by reduced PDA diameters or increased PDA maximum flow velocities (PDA V(max)), and 7 patients showed an ongoing response resulting in a closed PDA after the 1st cycle (47%). Of the 8 non-responders, 7 received a 2nd cycle with 2 further responders (29%). All non-responders to the 2nd course had a PDA V(max)<or=180 cm/s and increasing ductal diameters after the 3rd ibuprofen dose of the 1st course.

CONCLUSION

Maximum flow velocity and diameter of the PDA at the end of the 1st cycle discriminate between responders and non-responders to further ibuprofen treatment.

Implementation of a multidisciplinary guideline-driven approach to the care of the extremely premature infant improved hospital outcomes

AIM

To test the hypothesis that implementing guidelines for the standardized care of the extremely premature infant (<27 weeks) in the first week of life would improve patient outcomes in an all referral NICU.

METHODS

Data were collected on all infants <27 weeks gestational age and <7 days of age on admission cared for using these small baby guidelines (SBG), as well as on all age-matched infants admitted the year prior (comparison).

RESULTS

Thirty-seven patients were cared for utilizing the SBG and 40 patients were in the comparison group. There were no differences between the groups in gestational age, birthweight or age on admission. There was no difference in survival to discharge (73% SBG, 70% comparison). The mean length of stay for survivors was 112 +/- 38 days SBG and 145 +/- 76 days (p < 0.05) comparison group. Survival without BPD was greater in the SBG group (24%) than in the comparison group (9%; p < 0.05), and survival without severe IVH was greater in the SBG group (65%) than in the comparison group (38%; p < 0.01).

CONCLUSIONS

These data demonstrate that applying a unified approach to the care of the extremely premature infant in the first week of life resulted in a decrease in the length of hospitalization and improved patient outcomes.

Indomethacin, ibuprofen and gentamicin administered during late stages of glomerulogenesis do not reduce glomerular number at 14 days of age in the neonatal rat

Premature neonates are frequently administered indomethacin, ibuprofen and gentamicin during the period of active glomerulogenesis. These drugs are known to have nephrotoxic effects, but the morphological effect of these drugs is unknown. The purpose of this study was to determine whether administration of these drugs during the late stages of glomerulogenesis in the rat has an effect on glomerular endowment. Rat pups were given, intraperitoneally, indomethacin, ibuprofen or indomethacin and gentamicin for the first 5 days of their postnatal life. The pups were killed at 14 days of age at completion of glomerulogenesis. The total number of glomeruli in the left kidney was determined by the physical disector/fractionator stereological technique. There was no difference between treatment groups in total number of glomeruli per kidney (P = 0.45). There were significantly fewer glomeruli per gram of kidney in those rat pups that had received indomethacin or ibuprofen (P < 0.0001). The reduction in the number of glomeruli per gram of kidney may indicate augmented growth of nephron tubules and/or collecting ducts, and/or be a consequence of oedema secondary to drug exposure. Further study is required to determine whether reduced glomerular number is seen in older animals or following exposure to these drugs at different time-points in kidney development.

Therapeutic management of patent ductus arteriosus

Management of patent ductus arteriosus (PDA) in premature neonates has always been a challenge to the neonatologist and continues to be a controversial topic. Indications for treatment are not clear. Approximately 40% of ductus arteriosus close spontaneously even in extremely-low-birth-weight neonates. Prophylactic or early pre-symptomatic treatment may unnecessarily expose these babies, in whom the ductus might close spontaneously, to pharmacologic agents and their adverse effects. On the other hand, with advancing postnatal age, delaying treatment could potentially decrease successful medical closure thereby increasing the rate of surgical ligation and the complications associated with surgery. We tried to develop some clinical guidelines for management of PDA in premature neonates based on evidence, or lack thereof, and experience.

Clinical and echocardiographic diagnosis of patent ductus arteriosus in premature neonates

The ductus arteriosus frequently fails to close in premature neonates. Considerable difference in opinion exists around what signifies a hemodynamically significant patent ductus arteriosus (PDA) and how reliable clinical signs are in determining the degree of the left-to-right shunting. Although reliance on clinical signs alone could delay the diagnosis of a PDA, there is insufficient evidence to suggest that early treatment improves outcome. Echocardiography is often used as the gold standard for diagnosing a PDA. A combination of echocardiographic measurements may assist in the early diagnosis of a PDA with a hemodynamically significant degree of left-to-right shunting, especially in extremely premature babies, where closure can be significantly delayed. Decision to treat PDA should be based on a combination of clinical signs and echocardiographic parameters. Monitoring B-type natriuretic peptide may be useful in the diagnosing neonates with symptomatic PDA.

Patent ductus arteriosus therapy: impact on neonatal and 18-month outcome

OBJECTIVE

The purpose of this work was to evaluate therapy for patent ductus arteriosus as a risk factor for death or neurodevelopmental impairment at 18 to 22 months, bronchopulmonary dysplasia, or necrotizing enterocolitis in extremely low birth weight infants.

METHODS

We studied infants in the National Institute of Child Health and Human Development Neonatal Research Network Generic Data Base born between 2000 and 2004 at 23 to 28 weeks' gestation and at <1000-g birth weight with patent ductus arteriosus. Patent ductus arteriosus therapy was evaluated as a risk factor for outcomes in bivariable and multivariable analyses.

RESULTS

Treatment for subjects with patent ductus arteriosus (n = 2838) included 403 receiving supportive treatment only, 1525 treated with indomethacin only, 775 with indomethacin followed by secondary surgical closure, and 135 treated with primary surgery. Patients who received supportive therapy for patent ductus arteriosus did not differ from subjects treated with indomethacin only for any of the outcomes of interest. Compared with indomethacin treatment only, patients undergoing primary or secondary surgery were smaller and more premature. When compared with indomethacin alone, primary surgery was associated with increased adjusted odds for neurodevelopmental impairment and bronchopulmonary dysplasia in multivariable logistic regression. Secondary surgical closure was associated with increased odds for neurodevelopmental impairment and increased adjusted odds for bronchopulmonary dysplasia but decreased adjusted odds for death. Risk of necrotizing enterocolitis did not differ among treatments. Indomethacin prophylaxis did not significantly modify these results.

CONCLUSIONS

Our results suggest that infants treated with primary or secondary surgery for patent ductus arteriosus may be at increased risk for poor short- and long-term outcomes compared with those treated with indomethacin. Prophylaxis with indomethacin in the first 24 hours of life did not modify the subsequent outcomes of patent ductus arteriosus therapy.

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

OBJECTIVE

We conducted a multicenter, randomized, controlled trial to determine whether higher doses of indomethacin would improve the rate of patent ductus arteriosus (PDA) closure.

STUDY DESIGN

Infants (<28 weeks gestation) who received a conventional, prophylactic 3-dose course of indomethacin were eligible if they had continued evidence of persistent ductus patency on an echocardiogram obtained before the third prophylactic indomethacin dose. Infants (n = 105) were randomized to receive an extended 3-day course of either low-dose (0.1 mg/kg/d) or higher-dose (0.2 or 0.5 mg/kg/d) indomethacin. An echocardiogram was obtained 24 hours after the last dose of study drug.

RESULTS

Despite increasing serum indomethacin concentrations by 2.9-fold in the higher-dose group, we failed to detect a significant decrease in the rate of persistent PDA (low = 52%; higher = 45%, P = .50). The higher-dose group had a significantly higher occurrence of serum creatinine >2 mg/100 mL (low = 6%, higher = 19%, P < .05) and moderate/severe retinopathy of prematurity (ROP) (low = 15%, higher = 36%, P < .025). The incidence of moderate/severe ROP was directly related to the poststudy indomethacin concentrations (odds ratio = 1.75, confidence interval: 1.15-2.68, P < .01).

CONCLUSION

Increasing indomethacin concentrations above the levels achieved with a conventional dosing regimen had little effect on the rate of PDA closure but was associated with higher rates of moderate/severe ROP and renal compromise.

Factors affecting successful closure of hemodynamically significant patent ductus arteriosus with indomethacin in extremely low birth weight infants

BACKGROUND

The incidence of patent ductus arteriosus (PDA) is high in extremely low birth weight (ELBW) infants. Indomethacin has been widely used in the prophylaxis and treatment of hemodynamically significant PDA. This retrospective study was undertaken to identify factors such as birth weight, gestational age, gender, fetal growth retardation, ductal size, timing of the first dose of indomethacin and side effects of indomethacin, which may affect the successful closure of the PDA with indomethacin in ELBW infants.

METHODS

A cohort of 139 ELBW infants who had received indomethacin treatment for PDA during a consecutive period of more than three years (September 2000 to December 2003) was retrospectively analyzed. Administration

RESULTS

of indomethacin was associated with closure of PDA in 108 (77.7%) of 139 ELBW infants, and only 19.4% of infants required surgical ligation of the ductus eventually. There was no significant relationship between closure of PDA with gestational age, gender, fetal growth retardation, and ductal size. A higher birth weight and early use of indomethacin after birth could significantly increase the closure rate of PDA (P<0.05). Side effects of indomethacin such as transient oliguria and hyponatremia during indomethacin therapy did not affect PDA closure.

CONCLUSIONS

Indomethacin is effective for the treatment of PDA in ELBW infants. A higher rate of ductal closure is related to the increase of birth weight. PDA closure with indomethacin is age-related, and early administration of indomethacin could increase PDA closure and reduce the incidence of hyponatremia. There is no significant difference in major morbidities such as bronchopulmonary dysplasia (BPD), intraventricular hemorrhage (IVH), necrotizing enterocolitis (NEC), and retinopathy of prematurity (ROP) after early treatment. Early screening for hemodynamically significant PDA in ELBW infants and early treatment with indomethacin are recommended.

Surgical versus medical treatment with cyclooxygenase inhibitors for symptomatic patent ductus arteriosus in preterm infants

BACKGROUND

Patent ductus arteriosus (PDA) with significant left to right shunt in preterm infants increases morbidity and mortality. Early closure of the ductus arteriosus may be achieved pharmacologically using cyclooxygenase inhibitors or by surgery. The efficacy of both treatment modalities is well established. However, the preferred initial treatment of a symptomatic PDA in a preterm infant, surgical ligation or treatment with indomethacin, has not been well established.

OBJECTIVES

To compare the effect of surgical ligation of PDA vs. medical treatment with cyclooxygenase inhibitors (using indomethacin, ibuprofen, or mefenamic acid), each used as the initial treatment, on neonatal mortality in preterm infants with a symptomatic PDA.

SEARCH STRATEGY

The standard search strategy of the Cochrane Neonatal Review Group was used. This included search of electronic databases: Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 2, 2007), MEDLINE (1966 - July 2007), CINAHL (1982 - July 2007), EMBASE (1980 - July 2007); and hand search of abstracts of Pediatric Academic Societies annual meetings published in Pediatric Research (1990 - April 2002) or on line from May 2002 -July 2007. No language restrictions were applied.

SELECTION CRITERIA

All trials 1) using randomized or quasi-randomized patient allocation, 2) in preterm infants < 37 weeks gestational age or low-birth-weight infants (< 2500 grams) with symptomatic PDA in the neonatal period (< 28 days) and 3) comparing surgical ligation with medical treatment with cyclooxygenase inhibitors, each used as the initial treatment for closure of PDA.

DATA COLLECTION AND ANALYSIS

Assessment of methodological quality and extraction of data for included trials was undertaken independently by the authors. RevMan 4.1 was used for analysis of the data.

MAIN RESULTS

Only one study, trial B in the report of Gersony 1983, was found eligible. No additional studies were identified in the literature searches performed in July 2007. The trial compared the effect of surgical ligation of PDA vs. medical treatment with indomethacin, each used as the primary treatment. No trials comparing surgery to other cyclooxygenase inhibitors (ibuprofen, mefenamic acid) were found. Trial B of Gersony 1983 enrolled 154 infants. The study found no statistically significant difference between surgical closure and indomethacin treatment in mortality during hospital stay, chronic lung disease, other bleeding, necrotizing enterocolitis, sepsis, creatinine level, or intraventricular hemorrhage. There was a statistically significant increase in the surgical group in incidence of pneumothorax [RR 2.68 (95% CI 1.45, 4.93); RD 0.25 (95% CI 0.11, 0.38); NNH 4 (95% CI 3, 9)] and retinopathy of prematurity stage III and IV [RR 3.80 (95% CI 1.12, 12.93); RD 0.11 (95% CI 0.02, 0.20), NNH 9 (95% CI 5, 50] compared to the indomethacin group. There was as expected a statistically significant decrease in failure of ductal closure rate in the surgical group as compared to the indomethacin group: [RR 0.04 (95% CI 0.01, 0.27); RD -0.32 (95% CI -0.43, -0.21), NNT 3 (95% CI 2, 4)].

AUTHORS' CONCLUSIONS

The data regarding net benefit/harm are insufficient to make a conclusion as to whether surgical ligation or medical treatment with indomethacin is preferred as initial treatment for symptomatic PDA in preterm infants. It should be noted that three recent observational studies indicated an increased risk for one or more of the following outcomes associated with PDA ligation; chronic lung disease, retinopathy of prematurity and neurosensory impairment . It is possible that the duration of the "waiting-time" and transport to another facility with surgical capacity to have the PDA ligated could adversely affect outcomes, as could the perioperative care.

Risk factors for persistent ductus arteriosus patency during indomethacin treatment

OBJECTIVE

To test the hypothesis that patent ductus arteriosus that fail to close with prostaglandin inhibition may be regulated by mechanisms that act independently of prostaglandin production.

STUDY DESIGN

We examined a cohort of 446 infants who were treated with indomethacin (within 15 hours of birth) to inhibit prostaglandin production. We used multiple logistic regression modeling to determine which perinatal/neonatal variables were most closely associated with the persistence of ductus patency in the presence of diminished prostaglandin production.

RESULTS

We identified 4 variables (immature gestational age, lack of exposure to antenatal betamethasone, severity of respiratory distress, and Caucasian race) that were significantly and independently associated with the degree of ductus patency.

CONCLUSION

Gestational age, antenatal glucocorticoid exposure, respiratory distress, and race are independent risk factors that appear to affect ductus closure even when indomethacin has been used to inhibit prostaglandin production. Future studies of these risk factors may identify new potential targets for patent ductus arteriosus treatment.

Patent ductus arteriosus: lack of evidence for common treatments

Patent ductus arteriosus (PDA) is a common diagnosis among extremely premature infants, especially in those with lung disease. Treatments are often used to close the PDA. Despite nearly three decades of research, the question of whether the benefits of treatments to prevent ductal patency or promote closure outweigh the risks of these treatments remains unanswered. The authors rarely use treatments designed to close the PDA. This article reviews three considerations in support of this restrained approach: rates of spontaneous closure of the ductus arteriosus; adverse effect of persistent ductal patency; and benefits and risks of treatments for closure.

Renal glomeruli and tubular injury following indomethacin, ibuprofen, and gentamicin exposure in a neonatal rat model

Indomethacin, ibuprofen, and gentamicin are commonly administered to neonates between 24 and 28 wk gestation when glomerulogenesis is still occurring. Indomethacin is known to cause renal failure in up to 25% of infants treated. Possible morphologic effects of these drugs are largely unknown. The purpose of this study was to determine the type of renal changes found on light (LM) and electron microscopy (EM) following administration of indomethacin, ibuprofen, and gentamicin in a neonatal rat model. Rat pups were exposed to indomethacin or ibuprofen and/or gentamicin antenatally for 5 d before birth or postnatally for 5 d from d 1 of life. Pups were killed at 14 d of age. LM examination in all indomethacin- and ibuprofen-treated pups both antenatally and postnatally showed vacuolization of the epithelial proximal tubules, interstitial edema, intratubular protein deposition but no significant glomerular changes. EM examination showed pleomorphic mitochondria and loss of microvilli in the tubules. The glomeruli showed extensive foot process effacement and irregularities of the glomerular basement membrane. EM changes were most marked in pups treated antenatally with ibuprofen, and indomethacin with gentamicin postnatally. Indomethacin, ibuprofen, and gentamicin cause significant change in glomerular and tubular structure in the neonatal rat model.

Calcium-dependent and calcium-sensitizing pathways in the mature and immature ductus arteriosus

Studies performed in sheep and baboons have shown that after birth, the normoxic muscle media of ductus arteriosus (DA) becomes profoundly hypoxic as it constricts and undergoes anatomic remodeling. We used isolated fetal lamb DA (pretreated with inhibitors of prostaglandin and nitric oxide production) to determine why the immature DA fails to remain tightly constricted during the hypoxic phase of remodeling. Under normoxic conditions, mature DA constricts to 70% of its maximal active tension (MAT). Half of its normoxic tension is due to Ca(2+) entry through calcium L-channels and store-operated calcium (SOC) channels. The other half is independent of extracellular Ca(2+) and is unaffected by inhibitors of sarcoplasmic reticulum (SR) Ca(2+) release (ryanodine) or reuptake [cyclopiazonic acid (CPA)]. The mature DA relaxes slightly during hypoxia (to 60% MAT) due to decreases in calcium L-channel-mediated Ca(2+) entry. Inhibitors of Rho kinase and tyrosine kinase inhibit both Ca(2+)-dependent and Ca(2+)-independent DA tension. Although Rho kinase activity may increase during gestation, immature DA develop lower tensions than mature DA, primarily because of differences in the way they process Ca(2+). Calcium L-channel expression increases with advancing gestation. Under normoxic conditions, differences in calcium L-channel-mediated Ca(2+) entry account for differences in tension between immature (60% MAT) and mature (70% MAT) DA. Under hypoxic conditions, differences in both calcium L-channel-dependent and calcium L-channel-independent Ca(2+) entry, account for differences in tension between immature (33% MAT) and mature (60% MAT) DA. Stimulation of Ca(2+) entry through reverse-mode Na(+)/Ca(2+) exchange or CPA-induced SOC channel activity constrict the DA and eliminate differences between immature and mature DA during both hypoxia and normoxia.

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.

Indomethacin prophylaxis or expectant treatment of patent ductus arteriosus in extremely low birth weight infants?

BACKGROUND

Indomethacin prophylaxis or expectant treatment are common strategies for the prevention or management of symptomatic patent ductus arteriosus (sPDA).

OBJECTIVE

To compare the clinical responses of extremely low birth weight (ELBW) infants to indomethacin prophylaxis with that of other infants who were managed expectantly by being treated with indomethacin or surgically only after an sPDA was detected.

METHODS

Retrospective cohort investigation of 167 ELBW infants who received indomethacin prophylaxis (study) and 167 ELBW infants (control) treated expectantly who were matched by year of birth (1999 to 2006), birth weight, gestational age (GA) and gender.

RESULTS

Mothers of the two groups of infants were comparable demographically and on the history of preterm labor, pre-eclampsia, antepartum steroids and cesarean delivery. Study and control infants were similar in birth weight, GA, low 5 min Apgar scores, surfactant administration, the need for arterial blood pressure control, bronchopulmonary dysplasia and neonatal mortality. Necrotizing enterocolitis, spontaneous intestinal perforations, intraventricular hemorrhage grade III to IV, periventricular leukomalacia and stage 3 to 5 retinopathy of prematurity occurred also with similar frequency in both groups of infants. In the indomethacin prophylaxis group, 29% of the infants developed sPDA, and of them 38% responded to indomethacin treatment. In the expectantly treated group, 37% developed sPDA, and of them 59% responded to indomethacin treatment. Overall, surgical ligation rate for sPDA was similar between both groups of patients.

CONCLUSION

In our experience, indomethacin prophylaxis does not show any advantages over expectant early treatment on the management of sPDA in ELBW infants. Although no deleterious effects were observed, prophylaxis exposed a significant number of infants who may have never developed sPDA, to potential indomethacin-related complications.

Treatment strategies to prevent or close a patent ductus arteriosus in preterm infants and outcomes

OBJECTIVE

To describe the current use of treatments to prevent or treat patent ductus arteriosus (PDA) in preterm infants, examine the association between different treatment strategies and neonatal outcomes and review the variation in these practices between centers.

STUDY DESIGN

Cohort study of infants born between 23 and 30 weeks gestation managed by the Pediatrix Medical Group from 1997 to 2004. We collected data on demographics, indomethacin and ligation, and outcomes of the following five groups: prophylactic indomethacin treatment: infants treated with indomethacin on day of life (DOL) 0 or 1; indicated indomethacin treatment: infants treated with indomethacin after DOL 1; PDA without treatment: infants with a PDA without report of treatment; ligation only: infants with a PDA ligation without use of indomethacin and no PDA: infants without a PDA and without treatment.

RESULTS

There were 6189 (18%) patients who received prophylactic indomethacin, 5690 (16%) patients received indicated treatment, 3886 (11%) patients had a PDA without treatment, 702 (2%) patients received ligation only and 18 136 (52%) patients had no PDA. In multivariate analysis, mortality among survivors to 2 days of age was lower (odds ratio (OR) 0.6, 95% confidence interval (CI) 0.5 to 0.7, P<0.01) and chronic lung disease, isolated intestinal perforation and severe retinopathy of prematurity (stages 3 and 4) were higher (OR 1.5, 95% CI 1.3 to 1.6, P<0.01; OR 1.5, 95% CI 1.1 to 2.0, P<0.01 and 1.4, 95% CI 1.2 to 1.6, P<0.01, respectively) in the indicated treatment group compared with the PDA without treatment group. The proportion of infants receiving prophylactic indomethacin among all infants and infants receiving indicated treatment among neonates with a report of a PDA varied by site from 0 to 59% (median 9.5%) and 0 to 100% (median 62%), respectively.

CONCLUSIONS

Indomethacin use for intraventricular hemorrhage prevention and/or treatment of a PDA is common, but the selection of infants for treatment, and the decision of when and how to treat vary widely between centers. Our findings suggest the need for randomized, placebo-controlled trials of the effect of treatment of the PDA in preterm infants.

Indomethacin use for the management of patent ductus arteriosus in preterms: a web-based survey of practice attitudes among neonatal fellowship program directors in the United States

The objective of this study was to determine whether neonatal-perinatal fellowship programs (NFTPs) in the United States vary in indomethacin use for the management of patent ductus arteriosus (PDA) in < or =28 week gestational age infants at birth. A 53-item web-based survey was sent to 84 NFTP directors who received prenotification, followed 2 weeks later by a reminder letter. A total of 56 NFTP directors responded (67% maximum response rate). Wide variation exists in the maximum number of indomethacin courses used to close ductus, use of indomethacin for reopened PDA beyond 14 days, ductal closure definition, contraindications before consideration of indomethacin, interventions for contraindications, and reported ductal closer rate after each indomethacin course. Indomethacin therapy for symptomatic PDA and short course of indomethacin are common practices. Indomethacin use for the management of PDA in premature infants varies among NFTP directors. Practice attitudes may explain variations in ductal closure and ligation rates. Because practice variations may have implications for long-term outcome of vulnerable premature infants, studies relevant to the management of PDA in premature infants are needed.

Near-infrared spectroscopy as a screening tool for patent ductus arteriosus in extremely low birth weight infants

BACKGROUND

Patent ductus arteriosus (PDA) is frequent and potentially pathologic in preterm infants. A simple bedside tool to screen for ductal patency would assist in the care of extremely low birth weight (ELBW) infants.

OBJECTIVE

To investigate the utility of near-infrared spectroscopy (NIRS) in identifying ELBW infants who would benefit from early echocardiography.

METHODS

Tissue oxygen saturation (S(t)O(2)) was measured by NIRS in the lungs, brain, skeletal muscle and kidney of 20 ELBW infants. Comparisons were made between the S(t)O(2) in these organs and the need for intervention for a PDA. All studies were performed within the first 4 days of life. Similar measurements were performed following treatment with indomethacin in nine of the patients.

RESULTS

The S(t)O(2) of skeletal muscle (left deltoid) and kidney differed between the infants who were treated for PDA and those who were not (p = 0.01 for both). As a screen for a PDA requiring intervention, deltoid S(t)O(2) had sensitivity 77% and specificity 83%, and kidney S(t)O(2) had sensitivity 85% and specificity 83%. Following treatment with indomethacin, the low S(t)O(2) in the deltoid and kidney increased toward the range seen in patients who did not require treatment of a PDA. Inter- and intra-observer variability ranged from minimal to high.

CONCLUSION

This pilot study of a portable NIRS device shows encouraging efficacy in identifying ELBW infants who were likely to benefit from early echocardiography and subsequent intervention to close a PDA. Further study is warranted.