Prophylactic intravenous indomethacin for preventing mortality and morbidity in preterm infants

Periviable birth: executive summary of a Joint Workshop by the Eunice Kennedy Shriver National Institute of Child Health and Human Development, Society for Maternal-Fetal Medicine, American Academy of Pediatrics, and American College of Obstetricians and Gynecologists

This is an executive summary of a workshop on the management and counseling issues of women anticipated to deliver at a periviable gestation (broadly defined as 20 0/7 through 25 6/7 weeks of gestation), and the treatment options for the newborn. Upon review of the available literature, the workshop panel noted that the rates of neonatal survival and neurodevelopmental disabilities among the survivors vary greatly across the periviable gestations and are significantly influenced by the obstetric and neonatal management practices (for example, antenatal steroid, tocolytic agents and antibiotic administration; cesarean birth; and local protocols for perinatal care, neonatal resuscitation and intensive care support). These are, in turn, influenced by the variations in local and regional definitions of limits of viability. Because of the complexities in making difficult management decisions, obstetric and neonatal teams should confer prior to meeting with the family, when feasible. Family counseling should be coordinated with the goal of creating mutual trust, respect and understanding, and should incorporate evidence-based counseling methods. Since clinical circumstances can change rapidly with increasing gestational age, counseling should include discussion of the benefits and risks of various maternal and neonatal interventions at the time of counseling. There should be a plan for follow-up counseling as clinical circumstances evolve. The panel proposed a research agenda and recommended developing educational curricula on the care and counseling of families facing the birth of a periviable infant.

Pathogenesis and prevention of intraventricular hemorrhage

Intraventricular hemorrhage (IVH) is a major neurologic complication of prematurity. Pathogenesis of IVH is attributed to intrinsic fragility of germinal matrix vasculature and to the fluctuation in the cerebral blood flow. Germinal matrix exhibits rapid angiogenesis orchestrating formation of immature vessels. Prenatal glucocorticoid exposure remains the most effective means of preventing IVH. Therapies targeted to enhance the stability of the germinal matrix vasculature and minimize fluctuation in the cerebral blood flow might lead to more effective strategies in preventing IVH.

A predictive model for SIVH risk in preterm infants and targeted indomethacin therapy for prevention

Prophylactic indomethacin may decrease Severe Intraventricular Hemorrhage (SIVH). Our goal was to develop a predictive model for SIVH using parameters available by six hours of age. De-identified data for preterm infants born ≤ 34 weeks gestational age was abstracted from Vermont Oxford Network database. Using clinical variables available by 6 hrs of age the model was developed, and validated. Statistical methods were used to evaluate the ability of the model to discriminate infants with and without SIVH and, to compare observed and predicted risk. The model achieved excellent discrimination as indicated by ROC curve of 0·85. A good agreement was noted between observed and predicted risk (HLtest: p = 0·22). Application of the model to patients receiving indomethacin suggests a benefit at the highest risk levels. We have developed a valid predictive model for predicting SIVH as well as shown that exposure to indomethacin decreases the incidence of SIVH overall.

Management during the first 72 h of age of the periviable infant: an evidence-based review

After NICU admission the extremely immature newborn (EIN) requires evaluation and support of each organ system, and the integration of all those supports in a comprehensive plan of care. In this review, I attempt to analyze the evidence for treatment options after the initial transition, during the first 3 days of life, which have been shown to improve survival or short- or long-term morbidity. This review revealed several things: there is little available evidence from studies that have included significant numbers of EINs; interventions affecting different organ systems need to be co-ordinated as any intervention will have multiple effects; and future advances in treatment of this group of patients will require the installation of permanent research networks to have enough power to perform many studies needed to improve outcomes.

Dlx1 and Rgs5 in the ductus arteriosus: vessel-specific genes identified by transcriptional profiling of laser-capture microdissected endothelial and smooth muscle cells

Closure of the ductus arteriosus (DA) is a crucial step in the transition from fetal to postnatal life. Patent DA is one of the most common cardiovascular anomalies in children with significant clinical consequences especially in premature infants. We aimed to identify genes that specify the DA in the fetus and differentiate it from the aorta. Comparative microarray analysis of laser-captured microdissected endothelial (ECs) and vascular smooth muscle cells (SMCs) from the DA and aorta of fetal rats (embryonic day 18 and 21) identified vessel-specific transcriptional profiles. We found a strong age-dependency of gene expression. Among the genes that were upregulated in the DA the regulator of the G-protein coupled receptor 5 (Rgs5) and the transcription factor distal-less homeobox 1 (Dlx1) exhibited the highest and most significant level of differential expression. The aorta showed a significant preferential expression of the Purkinje cell protein 4 (Pcp4) gene. The results of the microarray analysis were validated by real-time quantitative PCR and immunohistochemistry. Our study confirms vessel-specific transcriptional profiles in ECs and SMCs of rat DA and aorta. Rgs5 and Dlx1 represent novel molecular targets for the regulation of DA maturation and closure.

Survival and neurodevelopmental outcome of preterm infants born at 22-24 weeks of gestational age

BACKGROUND

The limits of viability in extremely premature infants are challenging for any neonatologists in developed countries. The neurological development and growth of extremely preterm infants have come to be the emerging issue following the management in the neonatal intensive care unit.

OBJECTIVE

To assess potential associations between changes in practice and survival/neurodevelopmental outcome, and clinical outcomes of extremely preterm infants born at the limit of viability studied in a tertiary center.

STUDY DESIGN

A retrospective study enrolled 51 infants who had no congenital disorders, and were born at 22-24 weeks of gestational age (GA) in 2000-2009 in our institution. Clinical variables and interventions were studied with regard to one-year survival and developmental quotient (DQ) at 3 years of age.

RESULTS

The one-year survival rate of 24 preterm infants born in 2005-2009 (79%) was higher than that of the 27 infants born in 2000-2004 (52%, p = 0.04). Infants born after 2005 underwent less tocolysis (54 vs. 94%, p < 0.01) and more frequently antenatal steroid therapy (32 vs. 6%, p = 0.01) than those born before 2004. The post-2005 survivors (n = 19) received more frequently indomethacin therapy (89 vs. 50%, p = 0.03) and early parenteral nutrition (95 vs. 36%, p < 0.01) than the pre-2004 survivors (n = 14). There were no differences in the proportion of infants who attained a DQ of >50 at 3 years of age between pre-2004 (9/13, 69%) and post-2005 groups (10/17, 59%). Multivariate analysis indicated that extremely premature birth at GA <24 weeks was the sole critical factor for a DQ of >50 in survivors.

CONCLUSIONS

The perinatal care after 2005 improved the overall survival rate, but not the neurological outcome of preterm survivors at the limit of viability. Neurodevelopmental impairments were associated with extremely premature birth at GA <24 weeks.

Intestinal muscularis propria increases in thickness with corrected gestational age and is focally attenuated in patients with isolated intestinal perforations

PURPOSE

Intestinal perforations are common in premature infants, leading to a diagnostic dilemma between necrotizing enterocolitis and isolated intestinal perforation (IIP). IIP is thought to result from a congenital or acquired absence of the muscularis propria. However, developmental events leading to IIP are not well understood. This study examines the relationship between corrected gestational age (CGA) and intestinal muscle development in controls and patients with IIP.

METHODS

Specimens from stillbirths and infants undergoing intestinal surgery from 8 to 48weeks' CGA were collected from 2005 to 2012. Twelve patients with IIP were identified. Control specimens were collected during 25 fetal autopsies and 39 bowel resections. In each case, three sections of intestine were examined histologically for muscularis mucosa, circular and longitudinal muscle thickness. Comparisons of control and perforated specimens were performed via linear regression and ANOVA.

RESULTS

Controls and adjacent normal segments in IIP showed a linear relationship between thickness of circular and longitudinal muscles with CGA. Circular and longitudinal muscles were thinner in perforated segments than in adjacent normals and CGA-matched controls (p<0.05).

CONCLUSION

Intestinal muscularis propria increases in thickness with CGA. Muscle thickness is focally attenuated in patients with isolated intestinal perforations, while the remaining intestine is normal, suggesting that primary repair is an appropriate treatment.

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.

Serial echocardiography in very preterm infants: a pilot randomized trial

AIM

To determine whether routine echocardiography increases diagnosis and treatment for patent ductus arteriosus (PDA) and whether randomized nondisclosure is a feasible strategy for studying PDA management.

METHODS

Two-centre, pilot randomized, controlled trial. 88 infants with birth weights ≤1250 grams and gestational ages ≤30 weeks were randomized to disclosure or nondisclosure of serial echocardiogram findings. Echocardiograms were performed at 3-5 and 7-10 days of life. The primary outcome was time to regain birth weight.

RESULTS

100% of echocardiograms in the disclosure group were disclosed; 16% (echocardiogram #1) and 29% (echocardiogram #2) were disclosed in the nondisclosure group. There was a statistically nonsignificant decrease in drug therapy for PDA in the nondisclosure group (adjusted odds ratio [AOR] 0.56, 95% confidence interval [CI] 0.24-1.34). There was no difference in time to regain birth weight or in other important neonatal outcomes. However, infants in the nondisclosure group were more likely to demonstrate appropriate weight loss and then regain birth weight within 7-14 days (AOR 2.64, 95% CI 1.08-6.44).

CONCLUSION

Randomized nondisclosure of echocardiograms is a feasible strategy for evaluation of approaches to PDA management in very preterm infants. Avoidance of routine echocardiography may reduce drug therapy for PDA without adverse clinical effects.

Management of patent ductus arteriosus in preterm infants--where do we stand?

Patent ductus arteriosus (PDA) in preterm infants is a controversial topic in the management of preterm neonates. There are no generally accepted guidelines for diagnosis, treatment, and follow-up of PDA, and few publications have covered the whole topic or have been conclusively summarized to give a proper direction for the treating physician. Major issues remain to be clarified, both with respect to diagnosis and treatment. The definition of hemodynamic significance varies because of different use of echocardiographic criteria and uncertainty about the role of biomarkers. The detailed risks and benefits of available treatment alternatives are still under investigation. There has been a general shift in the management of PDA in preterm neonates from the "aggressive approach" to a more "conservative approach," but the effects of this strategy on morbidity in a longer time perspective are not fully known. An individualized therapeutic strategy with special emphasis on identification of hemodynamically significance seems to be the way forward. In this review we put forward the scientific background in favor of a seemingly growing body of evidence against active treatment, but we raise caution against shying away from all forms of treatment or instituting them too late. Finally, we try to integrate the current knowledge into suggestions for the management of PDA in premature infants.

Clinical pharmacology of indomethacin in preterm infants: implications in patent ductus arteriosus closure

Indomethacin is a non-steroidal anti-inflammatory drug that is a potent inhibitor of prostaglandin E(2) synthesis. After birth, the ductus arteriosus closes spontaneously within 2-4 days in term infants. The major factor closing the ductus arteriosus is the tension of oxygen, which increases significantly after birth. Prostaglandin E(2) has the opposite effect to that of oxygen; it relaxes smooth muscle and tends to inhibit the closure of the ductus arteriosus. In preterm infants with respiratory distress syndrome, the ductus arteriosus fails to close (patent ductus arteriosus [PDA]) because the concentration of prostaglandin E2 is relatively high. PDA occurs in more than 70 % of neonates weighing less than 1,500 g at birth. The aim of this article was to review the published data on the clinical pharmacology of indomethacin in preterm infants in order to provide a critical analysis of the literature and a useful tool for physicians. The bibliographic search was performed electronically using the PubMed and EMBASE databases as search engines and February 2012 was the cutoff point. A remarkable interindividual variability was observed for the half-life (t(½)), clearance (CL), and volume of distribution (V(d)) of indomethacin. Prophylactic indomethacin consists of a continuous infusion of low levels of indomethacin and may be useful in preterm infants. Extremely preterm infants are less likely to respond to indomethacin. Infants with a postnatal age of 2 months do not respond to treatment with indomethacin. Indomethacin has several adverse effects, the most common of which is renal failure. An increase in serum creatinine of ≥0.5 % mg/dL after indomethacin was observed in about 10-15 % of the patients and creatinine returns to a normal level about 1 week after cessation of therapy. Indomethacin should be administered intravenously by syringe pump for at least 30 min to minimize adverse effects on cerebral, gastrointestinal, and renal blood flow velocities. A prolonged course of indomethacin appears to reduce the risk of severe intracranial hemorrhage and renal impairment in patients with PDA. In conclusion, indomethacin is a useful drug to treat PDA.

Impact of telemedicine on hospital transport, length of stay, and medical outcomes in infants with suspected heart disease: a multicenter study

BACKGROUND

Previous single-center studies have shown that telemedicine improves care in newborns with suspected heart disease. The aim of this study was to test the hypothesis that telemedicine would shorten time to diagnosis, prevent unnecessary transports, reduce length of stay, and decrease exposure to invasive treatments.

METHODS

Nine pediatric cardiology centers entered data prospectively on patients aged <6 weeks, matched by gestational age, weight, and diagnosis. Subjects born at hospitals with and without access to telemedicine constituted the study group and control groups, respectively. Data from patients with mild or no heart disease were analyzed.

RESULTS

Data were obtained for 337 matched pairs with mild or no heart disease. Transport to a tertiary care center (4% [n = 15] vs 10% [n = 32], P = .01), mean time to diagnosis (100 vs 147 min, P < .001), mean length of stay (1.0 vs 26 days, P = .005) and length of intensive care unit stay (0.96 vs 2.5 days, P = .024) were significantly less in the telemedicine group. Telemedicine patients were significantly farther from tertiary care hospitals than control subjects. The use of inotropic support and indomethacin was significantly less in the telemedicine group. By multivariate analysis, telemedicine patients were less likely to be transported (odds ratio, 0.44; 95% confidence interval, 0.23-0.83) and less likely to be placed on inotropic support (odds ratio, 0.16; 95% confidence interval, 0.10-0.28).

CONCLUSIONS

Telemedicine shortened the time to diagnosis and significantly decreased the need for transport of infants with mild or no heart disease. The length of hospitalization and intensive care stay and use of indomethacin and inotropic support were less in telemedicine patients.

Ibuprofen for the treatment of patent ductus arteriosus in preterm and/or low birth weight infants

BACKGROUND

Indomethacin is used as standard therapy to close a patent ductus arteriosus (PDA) but is associated with reduced blood flow to several organs. Ibuprofen, another cyclo-oxygenase inhibitor, may be as effective as indomethacin with fewer side effects.

OBJECTIVES

To determine the efficacy and safety of ibuprofen for closing a PDA in preterm and/or low birth weight infants. Seperate comparisons are presented for 1. ibuprofen (iv) compared with placebo; 2. ibuprofen (oral) compared with placebo; 3. ibuprofen (oral or iv) compared with other cyclo-oxygenase inhibitors (given iv or orally); 4. ibuprofen (oral) versus indomethacin (given iv or orally); 5. ibuprofen (oral) versus iv ibuprofen; 6. high dose versus standard dose of iv ibuprofen; 7. early versus expectant administration of iv ibuprofen.

SEARCH METHODS

We searched The Cochrane Library, MEDLINE, EMBASE, Clincialtrials.gov, Controlled-trials.com, www.abstracts2view.com/pas, and personal files in July 2012.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials of ibuprofen for the treatment of a PDA in newborn infants.

DATA COLLECTION AND ANALYSIS

Data collection and analysis conformed to the methods of the Cochrane Neonatal Review Group.

MAIN RESULTS

Twenty-seven studies are included in this review. One study (n = 136) compared iv ibuprofen versus placebo. Ibuprofen reduced the composite outcome of infant deaths, infants who dropped out or required rescue treatment; risk ratio (RR) 0.58 (95% confidence interval (CI) 0.38 to 0.89); risk difference (RD) -0.22 (95% CI -0.38 to -06); number needed to benefit (NNTB) 5 (95% CI 3 to 17). One study (n = 64) compared oral ibuprofen with placebo. There was a significant reduction in the failure rate to close a PDA; RR 0.26 (95% CI 0.11 to 0.62); RD -0.44 (95% CI -0.65 to -0.23); NNTB 2 (95% CI 2 to 4). Failure rates for PDA closure with ibuprofen (oral or iv) compared with indomethacin (oral or iv) was reported in 20 studies (n = 1019 infants). There was no significant difference between the groups; typical RR 0.98 (95% CI 0.80 to 1.20) I(2) = 0%; typical RD -0.01 (95% CI -0.06 to 0.05); I(2) = 0%. The risk of developing necrotising enterocolitis (NEC) was reduced for ibuprofen (15 studies (n = 865); typical RR 0.68 (95% CI 0.47 to 0.99); typical RD -0.04 (95% CI -0.08 to -0.00; (P = 0.04); NNTB 25 (95% CI 13, infinity); I(2) = 0%). The duration of ventilatory support was reduced with ibuprofen (oral or iv) compared with iv or oral indomethacin (six studies, n = 471) mean difference (MD) -2.35 days (95% CI -3.71 to -0.99); I(2) = 19%. Failure rates for PDA closure with oral ibuprofen compared with indomethacin (oral or iv) were reported in seven studies (n = 189 infants). There was no significant difference between the groups; typical RR 0.82 (95% CI 0.52 to 1.29); typical RD -0.06 (95% CI -0.18 to 0.06). The risk of NEC was reduced with oral ibuprofen compared with indomethacin (oral or iv) six studies (n = 166); typical RR 0.44 (95% CI 0.23 to 0.82); RD -0.15 (95% CI -0.25 to -0.04); NNTB 7 (95% CI 4 to 25). There was no heterogeneity for this outcome. There was a decreased risk of failure to close a PDA with oral ibuprofen compared with iv ibuprofen, three studies (n = 236) typical RR 0.37 (95% CI 0.23 to 0.61); typical RD -0.24 (95% CI -0.35 to -0.13); NNTB 4 (95% CI 3 to 8). There was less evidence of transient renal insufficiency in infants who received ibuprofen compared with indomethacin. High dose versus standard dose of iv ibuprofen and early versus expectant administration of iv ibuprofen have only been studied in two trials.

AUTHORS' CONCLUSIONS

Ibuprofen is as effective as indomethacin in closing a PDA and reduces the risk of NEC and transient renal insufficiency. Given the reduction in NEC ibuprofen currently appears to be the drug of choice. Oro-gastric administration of ibuprofen appears at least as effective as iv administration. Too few patients have been enrolled in studies assessing the effectiveness of a high dose of ibuprofen versus the standard dose and early versus expectant administration of ibuprofen to make recommendations. Studies are needed to evaluate the effect of ibuprofen compared with indomethacin treatment on longer-term outcomes in infants with PDA.

Neurodevelopmental outcomes following two different treatment approaches (early ligation and selective ligation) for patent ductus arteriosus

OBJECTIVE

To examine whether a change in the approach to managing persistent patent ductus arteriosus (PDA) from early ligation to selective ligation is associated with an increased risk of abnormal neurodevelopmental outcomes.

STUDY DESIGN

In 2005, we changed our PDA treatment protocol for infants born at ≤27 6/7 weeks' gestation from an early ligation approach, with prompt PDA ligation if the ductus failed to close after indomethacin therapy (period 1: January 1999 to December 2004), to a selective ligation approach, with PDA ligation performed only if specific criteria were met (period 2: January 2005 to May 2009). All infants in both periods received prophylactic indomethacin. Multivariate analysis was used to compare the odds of a composite abnormal neurodevelopmental outcome (Bayley Mental Developmental Index or Cognitive Score <70, cerebral palsy, blindness, and/or deafness) associated with each treatment approach at age 18-36 months (n = 224).

RESULTS

During period 1, 23% of the infants in follow-up failed indomethacin treatment, and all underwent surgical ligation. During period 2, 30% of infants failed indomethacin, and 66% underwent ligation after meeting prespecified criteria. Infants treated with the selective ligation strategy demonstrated fewer abnormal outcomes than those treated with the early ligation approach (OR, 0.07; P = .046). Infants who underwent ligation before 10 days of age had an increased incidence of abnormal neurodevelopmental outcome. The significant difference in outcomes between the 2 PDA treatment strategies could be accounted for in part by the earlier age of ligation during period 1.

CONCLUSION

A selective ligation approach for PDAs that fail to close with indomethacin therapy is not associated with worse neurodevelopmental outcomes at age 18-36 months.

Periventricular hemorrhage: a problem still today

Periventricular hemorrhage (PVH) is the result of "temporary" fragile blood vessels and unstable circulation in the brain of very premature infants. Antenatal corticosteroids have substantially reduced PVH. Avoidance of intrapartum hypoxia and birth trauma has probably helped as has better cardio-respiratory stabilization after delivery. Increased survival of the highest risk infants under 26weeks gestation means that there are probably 800-900 infants with severe PVH annually in the UK. Delayed cord clamping could probably reduce PVH further. Various medications can reduce PVH but have not been widely adopted as the imaging has not translated into reduced disability. Posthemorrhagic ventricular dilatation (PHVD) and parenchymal hemorrhagic infarction both greatly increase disability. Treatment of PHVD is based on avoiding pressure and gross distortion of the vulnerable white matter. Further research needs to investigate whether treating subtle seizures, removing blood or blocking free radicals or inflammation will improve prognosis.

Preterm patent ductus arteriosus: should we treat it?

Debate about the importance of the preterm patent ductus arteriosus (PDA) remains unresolved. Ultrasound studies of PDA have suggested that the haemodynamic impact may be much earlier after birth than previously thought, but we still do not know when to treat a PDA. Studies that have tested symptomatic or pre-symptomatic treatment are mainly historical and have not tested the effect of no treatment. Prophylactic treatment is the best studied regimen, but improvements in some short-term outcomes do not translate to any difference in longer term outcomes. Neonatologists have been reluctant to engage in trials that test treatment against not treating at all or very rarely. Targeting treatment on the basis of the early post-natal constrictive response of the duct is currently being tested as a possible strategy.

Molecular mechanisms regulating the vascular prostacyclin pathways and their adaptation during pregnancy and in the newborn

Prostacyclin (PGI(2)) is a member of the prostanoid group of eicosanoids that regulate homeostasis, hemostasis, smooth muscle function and inflammation. Prostanoids are derived from arachidonic acid by the sequential actions of phospholipase A(2), cyclooxygenase (COX), and specific prostaglandin (PG) synthases. There are two major COX enzymes, COX1 and COX2, that differ in structure, tissue distribution, subcellular localization, and function. COX1 is largely constitutively expressed, whereas COX2 is induced at sites of inflammation and vascular injury. PGI(2) is produced by endothelial cells and influences many cardiovascular processes. PGI(2) acts mainly on the prostacyclin (IP) receptor, but because of receptor homology, PGI(2) analogs such as iloprost may act on other prostanoid receptors with variable affinities. PGI(2)/IP interaction stimulates G protein-coupled increase in cAMP and protein kinase A, resulting in decreased [Ca(2+)](i), and could also cause inhibition of Rho kinase, leading to vascular smooth muscle relaxation. In addition, PGI(2) intracrine signaling may target nuclear peroxisome proliferator-activated receptors and regulate gene transcription. PGI(2) counteracts the vasoconstrictor and platelet aggregation effects of thromboxane A(2) (TXA(2)), and both prostanoids create an important balance in cardiovascular homeostasis. The PGI(2)/TXA(2) balance is particularly critical in the regulation of maternal and fetal vascular function during pregnancy and in the newborn. A decrease in PGI(2)/TXA(2) ratio in the maternal, fetal, and neonatal circulation may contribute to preeclampsia, intrauterine growth restriction, and persistent pulmonary hypertension of the newborn (PPHN), respectively. On the other hand, increased PGI(2) activity may contribute to patent ductus arteriosus (PDA) and intraventricular hemorrhage in premature newborns. These observations have raised interest in the use of COX inhibitors and PGI(2) analogs in the management of pregnancy-associated and neonatal vascular disorders. The use of aspirin to decrease TXA(2) synthesis has shown little benefit in preeclampsia, whereas indomethacin and ibuprofen are used effectively to close PDA in the premature newborn. PGI(2) analogs have been used effectively in primary pulmonary hypertension in adults and have shown promise in PPHN. Careful examination of PGI(2) metabolism and the complex interplay with other prostanoids will help design specific modulators of the PGI(2)-dependent pathways for the management of pregnancy-related and neonatal vascular disorders.

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.

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

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

Diagnosis of the preterm patent ductus arteriosus: clinical signs, biomarkers, or ultrasound?

The current uncertainty in relation to treatment of the preterm patent ductus arteriosus reflects limitations to our understanding of the pathophysiology of ductal shunting, most particularly which ducts matter to which babies and when they matter. Doppler ultrasound offers a pragmatic tool with which to assess ductal patency and shunt significance and to allow prediction of spontaneous and therapeutic closure. Biomarkers, such as B-type natriuretic peptide, and clinical signs may have a diagnostic role where ultrasound is not available and also possibly as an adjunct to echocardiography in determining the pathophysiological impact of a ductal shunt in an individual baby.

A quality improvement approach to optimizing medication use in the neonatal intensive care unit

Despite many years of heavy use in premature and critically ill newborns, surprisingly few medications have been rigorously tested in neonatal multicenter randomized clinical trials. Little is known about the pharmacology of these drugs at various birth weights, gestational ages, and chronologic ages. This article describes a quality improvement approach to evaluating and improving neonatal intensive care unit (NICU) medication use, with an emphasis on adaptation of drug use to the specific clinical NICU context and use of system-based changes to minimize harm and maximize clinical benefit.

The definition of a haemodynamic significant duct in randomized controlled trials: a systematic literature review

AIM

A patent ductus arteriosus (PDA) is associated with morbidity in preterm infants. Treatment is prescribed for a haemodynamically significant duct (HSDA), but its definition varies. We systematically reviewed the clinical and ultrasound criteria used for the definition of an HSDA.

METHODS

PubMed and the Cochrane library were searched for randomized trials evaluating ductal treatment. The included studies were explored, and we categorized clinical and ultrasound criteria used to define an HSDA.

RESULTS

Sixty-seven trials were included in our review. Forty-two were placebo-controlled trials, and 25 were comparative trials. The diagnosis of the PDA was made by clinical examination, followed by ultrasound in most trials. Most trials used clinical and ultrasound criteria to define an HSDA, but there was a wide variety in criteria and cut-offs used. Of the clinical criteria, a murmur or hyperdynamic circulation was most used, and of the ultrasound criteria, the left-atrium-to-aorta ratio (LA/Ao ratio) was most used.

CONCLUSION

We found a wide variety in the definition of an HSDA. This finding implies that comparison of studies is difficult. International consensus should be reached on the definition of an HSDA, which will make future studies more comparable.

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.

Neonatal posthemorrhagic hydrocephalus from prematurity: pathophysiology and current treatment concepts

OBJECT

Preterm infants are at risk for perinatal complications, including germinal matrix-intraventricular hemorrhage (IVH) and subsequent posthemorrhagic hydrocephalus (PHH). This review summarizes the current understanding of the epidemiology, pathophysiology, management, and outcomes of IVH and PHH in preterm infants.

METHODS

The MEDLINE database was systematically searched using terms related to IVH, PHH, and relevant neurosurgical procedures to identify publications in the English medical literature. To complement information from the systematic search, pertinent articles were selected from the references of articles identified in the initial search.

RESULTS

This review summarizes the current knowledge regarding the epidemiology and pathophysiology of IVH and PHH, primarily using evidence-based studies. Advances in obstetrics and neonatology over the past few decades have contributed to a marked improvement in the survival of preterm infants, and neurological morbidity is also starting to decrease. The incidence of IVH is declining, and the incidence of PHH will likely follow. Currently, approximately 15% of preterm infants who suffer severe IVH will require permanent CSF diversion. The clinical presentation and surgical management of symptomatic PHH with temporary ventricular reservoirs (ventricular access devices) and ventriculosubgaleal shunts and permanent ventriculoperitoneal shunts are discussed. Preterm infants who develop PHH that requires surgical treatment remain at high risk for other related neurological problems, including cerebral palsy, epilepsy, and cognitive and behavioral delay. This review highlights numerous opportunities for further study to improve the care of these children.

CONCLUSIONS

A better grasp of the pathophysiology of IVH is beginning to impact the incidence of IVH and PHH. Neonatologists conduct rigorous Class I and II studies to advance the outcomes of preterm infants. The need for well-designed multicenter trials is essential because of the declining incidence of IVH and PHH, variations in referral patterns, and neonatal ICU and neurosurgical management. Well-designed multicenter trials will eventually produce evidence to enable neurosurgeons to provide their smallest, most vulnerable patients with the best practices to minimize perioperative complications and permanent shunt dependence, and most importantly, optimize long-term neurodevelopmental outcomes.

Current Perspectives on Pathobiology of the Ductus Arteriosus

The ductus arteriosus (DA) shunts blood away from the lungs during fetal life, but at birth this shunt is no longer needed and the vessel rapidly constricts. Postnatal persistence of the DA, patent ductus arteriosus (PDA), is predominantly a detrimental condition for preterm infants but is simultaneously a condition required to maintain systemic blood flow for infants born with certain severe congenital heart defects. Although PDA in preterm infants is associated with significant morbidities, there is controversy regarding whether PDA is truly causative. Despite advances in our understanding of the pathobiology of PDA, the optimal treatment strategy for PDA in preterm infants is unclear. Here we review recent studies that have continued to elucidate the fundamental mechanisms of DA development and pathogenesis.

Early NT-proBNP is able to predict spontaneous closure of patent ductus arteriosus in preterm neonates, but not the need of its treatment

The objective of this study was to establish the potential utility of N-terminal pro-brain natriuretic peptide (NT-proBNP) in the management of patent ductus arteriosus (PDA). This was a monocentric prospective blind study that was conducted in a referral neonatal intensive care unit. The patients were very low-birth-weight/gestational-age neonates. Babies with cardiac congenital anomaly other than PDA, life-threatening congenital malformation, severe asphyxia at birth, persistent pulmonary hypertension, and death within the first week of life were excluded. Plasma NT-proBNP concentrations were determined on days 2, 4, and 7 of life. Echocardiography was performed on days 4 and 7. Results were blinded to clinicians. Only echographic results were available upon request. Thirty-one infants were included. NT-proBNP levels were significantly correlated to ductal size and to left atrial-to-aortic diameter ratio. The median NT-proBNP on both days 2 and 4 was significantly higher in neonates with later treated or persistent PDA. A level above 10.000 pg/mL at 48 h of age yielded a 100% positive and a 87% negative predictive value to exclude spontaneous ductal closure. However, no NT-proBNP threshold could predict which PDA would be judged necessary to treat. It was concluded that early low NT-proBNP values can be used as a reliable independent marker to predict spontaneous ductal closure in preterm neonates. Yet, high NT-proBNP levels should not be used to guide the decision to treat PDA, the risk being of treating many bystanding PDAs.

Effects of prophylactic indomethacin in extremely low-birth-weight infants with and without adequate exposure to antenatal corticosteroids

OBJECTIVE

To examine whether treatment with antenatal corticosteroids modifies the immediate and long-term effects of prophylactic indomethacin sodium trihydrate in extremely low-birth-weight infants.

DESIGN

Post hoc subgroup analysis of data from the Trial of Indomethacin Prophylaxis in Preterms.

SETTING

Thirty-two neonatal intensive care units in Canada, the United States, Australia, New Zealand, and Hong Kong.

PARTICIPANTS

A total of 1195 infants with birth weights of 500 to 999 g and known exposure to antenatal corticosteroids. We defined as adequate any exposure to antenatal corticosteroids that occurred at least 24 hours before delivery.

INTERVENTION

Indomethacin or placebo intravenously once daily for the first 3 days.

OUTCOME MEASURES

Death or survival to 18 months with cerebral palsy, cognitive delay, severe hearing loss, or bilateral blindness; severe periventricular and intraventricular hemorrhage; patent ductus arteriosus; and surgical closure of a patent ductus arteriosus.

RESULTS

Of the 1195 infants in this analysis cohort, 670 had adequate and 525 had inadequate exposure to antenatal corticosteroids. There was little statistical evidence of heterogeneity in the effects of prophylactic indomethacin between the subgroups for any of the outcomes. The adjusted P values for interaction were as low as .15 for the outcome of death or impairment at 18 months and as high as .80 for the outcome of surgical duct closure.

CONCLUSION

We find little evidence that the effects of prophylactic indomethacin vary in extremely low-birth-weight infants with and without adequate exposure to antenatal corticosteroids. Trial Registration clinicaltrials.gov Identifier: NCT00009646.

Ibuprofen for the prevention of patent ductus arteriosus in preterm and/or low birth weight infants

BACKGROUND

Patent ductus arteriosus (PDA) complicates the clinical course of preterm infants and increases the risk of adverse outcomes. Indomethacin has been the standard treatment to close a PDA but is associated with renal, gastrointestinal and cerebral side-effects. Ibuprofen has less effect on blood flow velocity to important organs.

OBJECTIVES

To determine the effectiveness and safety of prophylactic ibuprofen compared to placebo/no intervention in the prevention of PDA in preterm infants.

SEARCH STRATEGY

Randomized controlled trials of prophylactic ibuprofen were identified by searching in The Cochrane Library, MEDLINE, CINAHL, EMBASE and trials registries in December 2010.

SELECTION CRITERIA

Randomized or quasi-randomised controlled trials comparing ibuprofen with placebo/no intervention or other cyclo-oxygenase inhibitor drugs to prevent PDA in preterm and/or low birth weight infants.

DATA COLLECTION AND ANALYSIS

Outcomes data including presence of PDA on day three, need for surgical ligation or rescue treatment with cyclo-oxygenase inhibitors, mortality, intraventricular haemorrhage (IVH), renal, pulmonary and gastrointestinal complications were extracted. Meta-analyses were performed and treatment estimates are reported as typical weighted mean difference, relative risk (RR), risk difference (RD) and, if statistically significant, number needed to treat to benefit (NNT) or number needed to treat to harm (NNH) along with their 95% confidence intervals (CI).

MAIN RESULTS

In this update, seven studies (n = 931) comparing prophylactic ibuprofen with placebo/no intervention are included. Ibuprofen decreased the incidence of PDA on day three [typical RR 0.36 (95% CI 0.29 to 0.46); typical RD -0.27 (95% CI -0.32 to -0.21); NNT 4 (95% CI 3 to 5)], decreased the need for rescue treatment with cyclo-oxygenase inhibitors and decreased the need for surgical ligation. Results from two studies administering oral ibuprofen had similar results, but showed an increased risk of gastrointestinal bleeding (NNH 4, 95% CI 2 to 17). In the control group the spontaneous closure rate was 58% by day three. Ibuprofen negatively affects renal function. No significant differences in mortality, IVH, chronic lung disease were found.

AUTHORS' CONCLUSIONS

Prophylactic use of ibuprofen decreased the incidence of PDA, decreased the need for rescue treatment with cyclo-oxygenase inhibitors and decreased the need for surgical closure. In the control group, the PDA closed spontaneously by day three in 58% of the neonates. Prophylactic treatment exposes many infants to a drug that has concerning renal and gastrointestinal side effects without conferring any important short-term benefits and is not recommended. Until long-term follow-up results are published from the trials included in this updated review, no further trials of prophylactic ibuprofen are recommended.

Gastrointestinal complications associated with ibuprofen therapy for patent ductus arteriosus

OBJECTIVE

To review intestinal complications associated with ibuprofen treatment of patent ductus arteriosus (PDA).

STUDY DESIGN

Data from preterm infants treated with ibuprofen were retrospectively reviewed. χ(2) test and Fischer's exact test were used for univariate analyses. Multivariate analyses with logistic regression modeling were used to identify risk factors.

RESULT

One hundred and two infants were treated with ibuprofen for PDA. Nine (9/102, 8.8%) infants developed spontaneous intestinal perforation (SIP), whereas 93/102 (91.2%) did not. The mean (± s.d.) gestational age (GA) at birth in infants with and without SIP was 25.2 (± 1.3) vs 27.6 (± 2.4) weeks (P=0.02) and the median (interquartile) length of stay (LOS) was 109.5 (91.0 to 116.5) vs 75.0 (53.0 to 94.5) days (P=0.002), respectively. The mean (± s.d.) age at starting ibuprofen was 3.3 (± 1.3) vs 5.8 (± 3.5) days in infants with and without SIP, respectively (P=0.03). In logistic regression analyses, increasing GA and later initiation of ibuprofen treatment were protective against risk of SIP; odds ratio, 95% confidence interval (OR, 95% CI)=0.26 (0.09 to 0.75), P=0.01 and 0.63 (0.41 to 0.95), P=0.03, respectively.

CONCLUSION

Infants at lower GA are at risk of SIP when treated early with ibuprofen for symptomatic PDA.

Indomethacin prophylaxis revisited: changing practice and supportive evidence

Important short-term intermediate outcomes such as patent ductus arteriosus (PDA), severe intraventricular haemorrhage, surgical ligation of PDA and serious pulmonary haemorrhage correlate with worse neurosensory outcomes in extreme low birth weight infants. Indomethacin prophylaxis has been shown to significantly prevent such outcomes. However, this positive effect did not translate into neither prevention of bronchopulmonary dysplasia nor long-term neurosensory outcome. The indomethacin prophylaxis story is indeed a puzzling one to neonatal practitioners. We present a summary of evidence and possible explanations to the lack of appreciated long-term effect of indomethacin prophylaxis. As the trial of indomethacin prophylaxis for preterms trial is a major contributor to current evidence, a detailed critical analysis of its methodology is presented. Methodological concerns such as the use of a composite outcome, statistical power, anticipated side effects of indomethacin prophylaxis and lack of predictive validity of cognitive delay measurements are presented.

CONCLUSION

Conclusive evidence of indomethacin prophylaxis use in extreme low birth weight infants is still lacking. Future research should put more emphasis on parental preferences, synergistic effect of indomethacin prophylaxis and fluid restriction and early targeted approach to PDA management.

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

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