The fate of ductus arteriosus in infants at 23-27 weeks of gestation: from spontaneous closure to ibuprofen resistance

Association between endotypes of prematurity and pharmacological closure of patent ductus arteriosus: A systematic review and meta-analysis

Introduction

Endotypes leading to very and extremely preterm birth are clustered into two groups: infection/inflammation and dysfunctional placentation. We conducted a systematic review of observational studies exploring the association between these two endotypes and the pharmacological closure of patent ductus arteriosus (PDA) induced by cyclooxygenase (COX) inhibitors. Chorioamnionitis represented the infectious-inflammatory endotype, while dysfunctional placentation proxies were hypertensive disorders of pregnancy (HDP) and small for gestational age (SGA) or intrauterine growth restriction.

Methods

PubMed/Medline and Embase databases were searched. The random-effects odds ratio (OR) and 95% confidence interval (CI) were calculated for each association. We included 30 studies (12,639 infants).

Results

Meta-analysis showed a significant association between exposure to HDP and increased rate of pharmacological closure of PDA (17 studies, OR 1.41, 95% CI 1.10-1.81, p = 0.006). In contrast, neither chorioamnionitis (13 studies, OR 0.75, 95% CI 0.47-1.18, p = 0.211) nor SGA (17 studies, OR 1.20, 95% CI 0.96-1.50, p = 0.115) were significantly associated with the response to therapy. Subgroup analyses showed that the higher response to COX inhibitors in the HDP group was significant for indomethacin (OR 1.568, 95% CI 1.147-2.141, p = 0.005) but not for ibuprofen (OR 1.107, 95% CI 0.248-4.392, p = 0.894) or for the studies using both drugs (OR 1.280, 95% CI 0.935-1.751, p = 0.124). However, meta-regression showed that this difference between the drugs was not statistically significant (p = 0.404).

Discussion/Conclusion

Our data suggest that the pathologic condition that triggers prematurity may alter the response to pharmacological treatment of PDA. The DA of infants exposed to HDP appears to be more responsive to COX inhibitors.

Predictors of a non-response to prophylactic indomethacin for patent ductus arteriosus in preterm infants

BACKGROUND

Preterm infants are recommended for prophylactic indomethacin (PIND) to promote closure of patent ductus arteriosus (PDA) and reduce morbidity and mortality. This study investigated the predictive factors of a non-response to PIND for PDA in preterm-birth infants.

METHODS

Consecutive preterm-birth infants (gestational age: < 28 weeks) who received PIND between 2009 and 2019 were retrospectively enrolled. Seventy-six eligible participants were classified as PIND responders (N = 42) or non-responders (N = 34). Information on potential confounders in maternal obstetric and perinatal data were collected from medical records. Multiple logistic regression analysis was carried out to identify the prognostic factors of a PIND response in preterm-birth infants.

RESULTS

The prevalence of intrauterine infection and multiple births was significantly different between responders and non-responders to PIND (intrauterine infection: 2 [4.8%] vs. 8 [23.5%], P = 0.036; twins: 3 [7.1%] vs. 9 [ 26.5%], P = 0.029, respectively). In multivariate logistic regression analysis after adjustment for multiple births, intrauterine infection was a significant and independent predictive factor of a non-response to PIND (odds ratio [OR] 5.54, 95% confidence interval [CI] 1.05-29.2, P = 0.044). A remarkable association was also noted for multiple births with a non-response to PIND (OR 4.22, 95% CI 0.99-17.8, P = 0.050).

CONCLUSIONS

Intrauterine infection and multiple births were identified as potential risk factors of a non-response to PIND for PDA in preterm infants.

Sex Differences in Patent Ductus Arteriosus Incidence and Response to Pharmacological Treatment in Preterm Infants: A Systematic Review, Meta-Analysis and Meta-Regression

A widely accepted concept in perinatal medicine is that boys are more susceptible than girls to complications of prematurity. However, whether this ‘male disadvantage of prematurity’ also involves persistent patent ductus arteriosus (PDA) has been scarcely investigated. Our aim was to conduct a systematic review and meta-analysis on studies addressing sex differences in the risk of developing PDA among preterm infants. We also investigated whether the response to pharmacological treatment of PDA differs between boys and girls. PubMed/Medline and Embase databases were searched. The random-effects male/female risk ratio (RR) and 95% confidence interval (CI) were calculated. We included 146 studies (357,781 infants). Meta-analysis could not demonstrate sex differences in risk of developing any PDA (37 studies, RR 1.03, 95% CI 0.97 to 1.08), hemodynamically significant PDA (81 studies, RR 1.00, 95% CI 0.97 to 1.02), or in the rate of response to pharmacological treatment (45 studies, RR 1.01, 95% CI 0.98 to 1.04). Subgroup analysis and meta-regression showed that the absence of sex differences was maintained over the years and in different geographic settings. In conclusion, both the incidence of PDA in preterm infants and the response rate to pharmacological treatment of PDA are not different between preterm boys and girls.

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

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

Ductus arteriosus and failed medical therapy

BACKGROUND

Management of a patent ductus arteriosus (PDA) after pharmacological therapy failure in preterm neonates is controversial and shows marked practice variation. To evaluate which factors motivate the decision to ligate a PDA in clinical practice we examined several clinical and echocardiographic variables.

METHODS

We conducted a retrospective single center cohort study. We included infants born at less than 37 weeks of gestation, admitted to our neonatal intensive care between 01.01.2008 and 31.12.2015 with a PDA detected on echocardiography after two or three courses of medical therapy. Logistic regression analyses were used to predict surgical ligation for twelve clinical and nine echocardiographic variables separately. We used the multiple imputation technique for missing values.

RESULTS

A total of 89 neonates were included of which forty (45%), underwent surgical ligation of their PDA. In our final multivariate regression model, invasive respiratory support (OR 3.6, 95% CI 1.29-10.03), left atrial/aortic root ratio (OR 5.48, 95% CI 1.66-18.11) and presence of ductal steal (OR 3.82, 95% CI 1.47-9.91) were significant predictors for surgical ligation. The prediction model using clinical and echocardiographic variables explained 9% and 24% of the variability to ligate respectively, indicating significant residual variation due to unmeasured factors.

CONCLUSIONS

Our results indicate that invasive respiratory support, increased left atrial/aortic root ratio and the presence of ductal steal were important predictors for surgical ligation in our center. However, this explained only a small proportion of the variability, which emphasizes the need for evidence-based guidelines in the management of preterm neonates after failed pharmacological therapy for a PDA.

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

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

Comparison of oral acetaminophen with oral ibuprofen on closure of symptomatic patent ductus arteriosus in preterm neonates

Background:

Patent ductus arteriosus (PDA) is a common cause of morbidity in premature neonates. The purpose of this study was to compare the efficacy of oral ibuprofen and oral acetaminophen to closure of symptomatic PDA, in premature neonates with gestational age (GA) ≤32 weeks.

Materials and Methods:

This study was a randomized clinical trial with forty preterm neonates who were admitted in neonatal intensive care unit with symptomatic PDA and GA ≤32 weeks or birth body weight ≤1500 g. Twenty neonates received oral acetaminophen [Group A] and twenty neonates received oral ibuprofen [Group B] and compared with echocardiography finding each groups for closed PDA before and after treatment regiment.

Results:

Our results showed that the primary closure rate of PDA was 70% (95% confidence interval [CI]: 49.9%–90%) and 65% (95% CI: 54.3%–75.7%) in the acetaminophen and ibuprofen groups, respectively, and statistically no significant difference was observed between the two groups (P = 0.74).

Conclusion:

These findings suggest that there was no significant difference between the effectiveness of oral acetaminophen and oral ibuprofen on closing of PDA, but less adverse effects and contraindication for acetaminophen make it reasonable choice for the treatment of symptomatic PDA.

Early haemodynamically significant patent ductus arteriosus does not predict future persistence in extremely preterm infants

AIM

We assessed whether early haemodynamically significant patent ductus arteriosus (hsPDA) predicted persistent patent ductus arteriosus (PDA) in extremely preterm infants.

METHODS

This prospective observational study of 60 infants born at 22-27 weeks of gestational age (GA) without any major congenital anomalies or heart defects was conducted at Uppsala University Children's Hospital from November 2012 to May 2015. Respiratory and systemic circulatory parameters were continuously recorded, and echocardiographic examinations performed daily during the first three days of life. Pharmacological treatment was initiated if hsPDA was found on days two to seven. Persistent PDA was diagnosed if hsPDA remained after pharmacological treatment or pharmacological treatment was contraindicated.

RESULTS

The infants (56% male) had a median GA of 25 + 2 weeks and 50% received pharmacological treatment. PDA was persistent in 30% and ultimately closed or insignificant in 70%. hsPDA on days two to seven was not associated with future persistent PDA (p = 1.000). Mechanical ventilation (p = 0.025), high mean airway pressure (p = 0.020) and low ductal maximal flow velocity (V_max ) (p = 0.024) on day two were associated with future persistent PDA.

CONCLUSION

Early hsPDA did not predict persistent PDA, but the early need for assisted ventilation and low ductal V_max were associated with future persistent PDA in these extremely preterm infants.

Understanding the pathobiology in patent ductus arteriosus in prematurity-beyond prostaglandins and oxygen

The ductus arteriosus (DA) is probably the most intriguing vessel in postnatal hemodynamic transition. DA patency in utero is an active state, in which prostaglandin E₂ (PGE₂) and nitric monoxide (NO), play an important role. Since the DA gets programmed for postnatal closure as gestation advances, in preterm infants the DA frequently remains patent (PDA). PGE₂ exposure programs functional postnatal closure by inducing gene expression of ion channels and phosphodiesterases and anatomical closure by inducing intimal thickening. Postnatally, oxygen inhibits potassium and activates calcium channels, which ultimately leads to a rise in intracellular calcium concentration consequently inducing phosphorylation of the myosin light chain and thereby vasoconstriction of the DA. Since ion channel expression is lower in preterm infants, oxygen induced functional vasoconstriction is attenuated in comparison with full term newborns. Furthermore, the preterm DA is more sensitive to both PGE₂ and NO compared to the term DA pushing the balance toward less constriction. In this review we explain the physiology of DA patency in utero and subsequent postnatal functional closure. We will focus on the pathobiology of PDA in preterm infants and the (un)intended effect of antenatal exposure to medication on both fetal and neonatal DA vascular tone.

Low-dose intravenous acetaminophen versus oral ibuprofen for the closure of patent ductus arteriosus in premature neonates

Background:

Patent ductus arteriosus (PDA) is a common disease in premature neonates, which could occur in up to 50% of the neonates weighting <1000 g. PDA might induce hemodynamic and respiratory disorders and increase mortality and morbidity. This study aimed to compare the effectiveness of oral ibuprofen and a low dose of intravenous acetaminophen in the management of PDA.

Materials and Methods:

This randomized double-blind clinical trial was conducted on the preterm neonates with an equal gestational age of <34 weeks and weight of >1000 g with symptomatic PDA, who were admitted in Shahid Beheshti and Al-Zahra Hospitals Affiliated to Isfahan University of Medical Sciences, Iran. In total, 40 preterm neonates were examined, 20 of whom received 15 mg/kg/6 h of intravenous acetaminophen for 2 days and 20 infants received 10 mg/kg of intravenous ibuprofen on the 1^st day and 5 mg/kg for the next 2 days, and the results include vital signs and echocardiography findings were compared.

Results:

In the acetaminophen and ibuprofen groups, 16 (80%) and 17 neonates (85%) responded (PDA closure rate) to the treatment, respectively (P = 0.68). Furthermore, acetaminophen and ibuprofen have a similar effect on vital signs. Both drugs did not change in blood pressure, but they reduced the respiratory rate and heart rate after treatment.

Conclusion:

Low-dose acetaminophen compared to ibuprofen has an equal effectiveness in the closure of PDA.

Natural evolution of ductus arteriosus with noninterventional conservative management in extremely preterm infants born at 23-28 weeks of gestation

This study aimed to determine the natural course of patent ductus arteriosus (PDA) with noninterventional conservative management and whether the presence and/or prolonged duration of hemodynamically significant (HS) PDA increased the risk of mortality and morbidities in extremely preterm (EPT) infants. We retrospectively reviewed the medical records of EPT infants born at 23-28 weeks of gestation (n = 195) from January 2011 to June 2014, when PDA was managed with noninterventional conservative treatment. We stratified infants into three subgroups of 23-24, 25-26, and 27-28 weeks and analyzed the prevalence and natural evolution of HS PDA, defined as ventilator dependency and PDA size ≥2 mm. Multivariate regression analyses determined if the presence and/or prolonged duration of HS PDA increased the risk for mortality and/or morbidities. The overall incidence of HS PDA was 57% (111/195) at the end of the first postnatal week. In subgroup analyses, infants with 23-24 weeks of gestation had the highest incidence (93%, 50/54), with 64% (47/74) for 25-26 weeks and 21% (14/67) for 27-28 weeks. Six (5%) of 111 infants with HS PDA were discharged without ductus closure, 4 had spontaneous PDA closure on follow up, and device closure was performed for 2 infants. In the multivariate analyses, the presence or prolonged duration (per week) of HS PDA was not associated with the risk of mortality and/or morbidities. Spontaneous closure of HS PDA was mostly achieved, even in EPT infants, with a noninterventional conservative approach. In conclusion, our data showed the incidence and natural course of HS PDA in EPT infants and suggested that the presence or prolonged duration of HS PDA might not increase the rate of mortality or morbidities.

Ductus arteriosus outcome with focus on the initially patent but hemodynamically insignificant ductus in preterm neonates

BACKGROUND/OBJECTIVES

The hemodynamically insignificant (hisPDA) ductus arteriosus often progresses to hemodynamic significance. In this review, we sought risk factors predictive of progression.

METHODS

Early hisPDAs were subdivided into those that closed spontaneously vs. those that progressed to hsPDA.

RESULTS

Sixty percent of early hisPDAs subsequently progressed to hsPDAs. In all but one, the ductus never closed, but rather became progressively more significant over time. The echocardiographic parameters best associated with subsequent progression were an increased transductal diameter (1.81 ± 0.77 vs. 1.21 ± 0.44 mm; p < 0.001) and the presence of diastolic flow reversal. ROC curve analysis showed that the best ductal diameter criterion for predicting the progression to hsPDA was >1.4 (sensitivity = 91; specificity = 81). The combined morbidity score was higher in those infants who progressed to hsPDA as compared with those who did not (p = 0.0038).

CONCLUSIONS

Increased ductal diameter and diastolic flow reversal on the first echocardiogram were best correlated with progression of hisPDA to hsPDA.

Prediction of Therapeutic Response to Cyclooxygenase Inhibitors in Preterm Infants with Patent Ductus Arteriosus

Patent ductus arteriosus (PDA) is a morbid condition commonly seen in premature infants. Cyclooxygenase (COX) inhibitors, such as indomethacin and ibuprofen, are often used for the treatment of PDA in preterm infants, and they work by reducing the production of prostaglandin. However, as observed in clinical practice, not all PDAs in preterm infants can be closed using COX inhibitors. Some studies have demonstrated that gestational age, birth weight, B-type natriuretic peptide (BNP), and ductal diameter can predict the therapeutic responsiveness to COX inhibitors. This paper reviews the factors that can predict successful closure of the PDA in preterm infants using indomethacin or ibuprofen and presents new opinions and recent findings on this topic, including the predictive roles of intrauterine growth restriction, timing of the treatment, and the importance of platelet count and arterial pH. We also discuss the prospects for future studies to improve the individualized therapy of PDA in premature neonates.

Oral Paracetamol for Patent Ductus Arteriosus Rescue Closure

The objective of this study was to ascertain the efficacy of oral paracetamol in closing a symptomatic patent ductus arteriosus (PDA) when used as 'rescue' option. After obtaining ethics approval, a retrospective appraisal of the data from April 2014 to July 2015 was performed. Infants who were administered oral paracetamol either after unsuccessful therapy with ibuprofen or where it was considered contraindicated were included. A previously published echocardiographic scoring schema to stratify for ductal disease severity was used. Using univariate analysis, characteristics of infants with successful closure were compared with partial (a priori reduction in composite score by ≥ 50% of pretreatment) or no closure. Twenty infants with gestation age and birthweight of 25.7 ± 1.5 weeks and 724.1 ± 143 g, respectively, were studied. Complete closure was noted in 10 (50%) infants with additional four infants showing a significant reduction in haemodynamic shunting. Gestational age at birth and at therapy, chronological age at therapy, birthweight and total fluid intake were comparable between the two groups. The pre-therapy composite score had a significant association with successful closure (the higher the echocardiographic score, the lesser the closure). Concomitant furosemide therapy and late-onset sepsis had a high likelihood ratio of unsuccessful closure (11.01 [2-tailed, p = 0.005] and 5.3 [2-tailed, p = 0.07]), respectively. Oral paracetamol may be a possible therapeutic option in premature infants where therapy with first-line agents is unsuccessful or contraindicated. Concomitant sepsis and furosemide administration may affect successful therapy.

Oral pharmacological treatment for patent ductus arteriosus in premature neonates with hemodynamic repercussions

OBJECTIVE

To evaluate the efficacy of oral indomethacin, ibuprofen, and paracetamol in oral dosage form on patent ductus arteriosus (PDA) in premature neonates with significant clinical and hemodynamic repercussions (CHRs) and to determine the effect of these respective treatments on renal function.

METHODS

A retrospective study of cases of PDA in premature neonates in the Neonatal Intensive Care Unit was conducted. The treatments consisted of indomethacin [0.2 mg/(kg·d), 3-day cycle], ibuprofen [10 mg/(kg·d) followed by 5 mg/(kg·d), 3-day cycle], and paracetamol (15 mg/kg every 6 h, 5-day cycle). The drugs were administered as an oral solution. The following variables were considered: gestational age, newborn weight at birth, Apgar score, diuresis, serum creatinine and urea levels, and serum electrolyte levels (sodium and potassium).

RESULTS

Treatment with indomethacin presented efficacy of 87.5% in closure of the ductus with a mean outcome period of 3.5 d. In premature neonates with CHRs and contraindications for indomethacin, the initial treatment with either ibuprofen or paracetamol failed to close the ductus. However, when this treatment was followed by indomethacin, closure occurred in 66.7% of the neonates, with an outcome period of 9.66 d. The initial treatment with one cycle of ibuprofen followed by one or two cycles of paracetamol failed to close the ductus.

CONCLUSIONS

Oral indomethacin was effective for closure of the PDA in premature neonates with severe CHRs. Oral paracetamol or ibuprofen for PDA closure in premature neonates with severe CHRs and contraindications for indomethacin was ineffective. However, results in clinical improvements of neonates allowed the subsequent use of indomethacin and successful closure of the ductus. A significant reduction of diuresis occurred in neonates who were treated with indomethacin, either as a first-line treatment or after the failure of ibuprofen or paracetamol.

A conservative treatment of patent ductus arteriosus in very low birth weight infants

BACKGROUND

Treatment of the patent ductus arteriosus (PDA) in the preterm infant remains contentious. There are numerous options of the PDA management from early targeted treatment, late (symptomatic) treatment to no treatment at all.

AIMS

To evaluate a three different PDA management approaches in very low birth weight (VLBW) infants.

STUDY DESIGN

A retrospective observational time series study of three cohorts of VLBW infants born between 2004 and 2011.

SUBJECTS

Infants in Symptomatic Treatment Group (STG) were echocardiographically evaluated when clinical signs suggestive of a PDA were present and treated if a haemodynamically significant PDA was confirmed. Early Targeted Group (ETG) underwent echocardiography within the first 48h and infants received ibuprofen if a large PDA was present. Conservative Treatment Group (CTG) was screened by echocardiography on day seven of life; patients with PDA were managed with increased positive end expiratory pressure and fluid restriction as a first line intervention.

OUTCOMES

The primary outcome was medical and surgical treatment in the three time periods. Secondary outcomes included mortality, severe periventricular and intraventricular haemorrhage, respiratory distress syndrome and chronic lung disease.

RESULTS

There were 138 infants diagnosed with PDA; 52 infants in STG, 52 infants in ETG and 34 infants in CTG. Ibuprofen therapy and ligation were less frequent in CTG. There was significantly decreased incidence of chronic lung disease in CTG compared to STG (18% vs. 51%; p=0.003) and to ETG (18% vs. 46%; p=0.02). There was no difference in the other short term outcomes.

CONCLUSION

Conservative treatment of persistent ductus arteriosus in VLBW infants is a feasible option and future randomized trials of conservative management are warranted.

Mandatory Closure Versus Nonintervention for Patent Ductus Arteriosus in Very Preterm Infants

OBJECTIVE

To determine whether a nonintervention approach for treating hemodynamically significant patent ductus arteriosus (PDA) is associated with decreased mortality and/or morbidity compared with a mandatory closure approach in extremely low birth weight infants.

STUDY DESIGN

We reviewed the medical records of 178 infants of 23-26 weeks' gestational age with PDA, requiring ventilator treatment, and with hemodynamically significant PDA ≥2 mm in size. Mandatory closure was used during period I (July 2009 to December 2011, n = 81), and nonintervention was used during period II (January 2012 to June 2014, n = 97).

RESULTS

During period I, 64% of infants were first treated with indomethacin, and 82% were ultimately ligated surgically. During period II, no infant was treated with indomethacin and/or ligation. The average postnatal day of PDA closure was day 13 and day 44 during periods I and II, respectively. There was significantly more use of diuretics and fluid restriction during period II compared with period I. There was no difference in mortality or morbidities such as necrotizing enterocolitis or intraventricular hemorrhage. The incidence of bronchopulmonary dysplasia (BPD) and the propensity score adjusted OR of BPD were significantly lower during period II compared with period I.

CONCLUSIONS

Despite longer PDA exposure, nonintervention was associated with significantly less BPD compared with mandatory closure. Additional study is warranted to determine the benefits and risks of non-intervention for the hemodynamically significant PDA in extremely low birth weight infants.

Ibuprofen for Ductus Arteriosus Months after Birth

Ibuprofen is a well-known agent used to treat patent ductus arteriosus in preterm neonates in the first days of life. In the current case report we illustrate the potential use of ibuprofen in two preterm neonates 60 and 88 days after birth, respectively. To our knowledge, this is the first report on the effects of ibuprofen on patent ductus arteriosus in preterm newborns after months of life. These cases suggest that the ductus arteriosus does not become refractory for ibuprofen after the first days of life. Late closure of the duct with ibuprofen might still improve the cardiorespiratory condition and prevent infants from surgical closure. Controlled trials are necessary to further study these findings.

Paracetamol for the treatment of patent ductus arteriosus in preterm neonates: a systematic review and meta-analysis

OBJECTIVES

We performed a systematic review and meta-analysis of all the available evidence to assess the efficacy and safety of paracetamol for the treatment of patent ductus arteriosus (PDA) in neonates, and to explore the effects of clinical variables on the risk of closure.

DATA SOURCE

MEDLINE, Scopus and ISI Web of Knowledge databases, using the following medical subject headings and terms: paracetamol, acetaminophen and patent ductus arteriosus. Electronic and manual screening of conference abstracts from international meetings of relevant organisations. Manual search of the reference lists of all eligible articles.

STUDY SELECTION

Studies comparing paracetamol versus ibuprofen, indomethacin, placebo or no intervention for the treatment of PDA.

DATA EXTRACTION

Data regarding efficacy and safety were collected and analysed.

RESULTS

Sixteen studies were included: 2 randomised controlled trials (RCTs) and 14 uncontrolled studies. Quality of selected studies is poor. A meta-analysis of RCTs does not demonstrate any difference in the risk of ductal closure (Mantel-Haenszel model, RR 1.07, 95% CI 0.87 to 1.33 and RR 1.03, 95% CI 0.92 to 1.16, after 3 and 6 days of treatment, respectively). Proportion meta-analysis of uncontrolled studies demonstrates a pooled ductal closure rate of 49% (95% CI 29% to 69%) and 76% (95% CI 61% to 88%) after 3 and 6 days of treatment with paracetamol, respectively. Safety profiles of paracetamol and ibuprofen are similar.

CONCLUSIONS

Efficacy and safety of paracetamol appear to be comparable with those of ibuprofen. These results should be interpreted with caution, taking into account the non-optimal quality of the studies analysed and the limited number of neonates treated with paracetamol so far.

Predictors of successful closure of patent ductus arteriosus with indomethacin

OBJECTIVE

To determine whether platelet counts can predict the likelihood of successful closure of patent ductus arteriosus (PDA) with indomethacin.

STUDY DESIGN

This was a retrospective cohort study of infants <32 weeks' gestational age (GA) and birth weight <1500 g with PDA. Clinical characteristics between infants who achieved ductal closure with indomethacin and those who failed were compared. Multivariable logistic regression was used to identify predictors of successful ductal closure.

RESULTS

In infants with hemodynamically significant PDA, older GA (odds ratio=1.54; 95% confidence interval: 1.12 to 2.13), male gender (odds ratio=3.02; 95% confidence interval: 1.08 to 8.49) and higher platelet count (odds ratio=1.5; 95% confidence interval: 1.04 to 2.17) prior to indomethacin treatment were associated with successful ductal closure with indomethacin.

CONCLUSION

Older GA, male gender and higher platelet count at time of treatment of hemodynamically significant PDA are predictors of successful ductal closure with indomethacin.

Intravenous paracetamol with a lower dose is also effective for the treatment of patent ductus arteriosus in pre-term infants

INTRODUCTION

Haemodynamically significant patent ductus arteriosus is a significant cause of morbidity and mortality in pre-term infants. This retrospective study was conducted to investigate the usefulness of lower-dose paracetamol for the treatment of patent ductus arteriosus in pre-term infants.

MATERIALS AND METHODS

A total of 13 pre-term infants who received intravenous paracetamol because of contrindications or side effects to oral ibuprofen were retrospectively enrolled. In the first patient, the dose regimen was 15 mg/kg/dose, every 6 hours. As the patient developed significant elevation in transaminase levels, the dose was decreased to 10 mg/kg/dose, every 8 hours in the following 12 patients. Echocardiographic examination was conducted daily. In case of closure, it was repeated after 2 days and when needed thereafter in terms of reopening.

RESULTS

A total of 13 patients received intravenous paracetamol. Median gestational age was 29 weeks ranging from 24 to 31 weeks and birth weight was 950 g ranging from 470 to 1390 g. The median postnatal age at the first intravenous paracetamol dose was 3 days ranging from 2 to 9 days. In 10 of the 13 patients (76.9%), patent ductus arteriosus was closed at the median 2nd day of intravenous paracetamol ranging from 1 to 4 days. When the patient who developed hepatotoxicity was eliminated, the closure rate was found to be 83.3% (10/12).

CONCLUSION

Intravenous paracetamol may be a useful treatment option for the treatment of patent ductus arteriosus in pre-term infants with contrindication to ibuprofen. In our experience, lower-dose paracetamol is effective in closing the patent ductus arteriosus in 83.3% of the cases.

Current controversies in the management of patent ductus arteriosus in preterm infants

OBJECTIVE

Patent ductus arteriosus is very commonly seen in very low birth weight (VLBW) infants, affecting about one-third. The present review tries to identify the group of VLBW infants who need active intervention in day-to-day practice and to determine the mode of intervention, based on current published literatures.

METHODS

We searched the Cochrane library, MEDLINE, EMBASE and CINAHL databases, and reference that of identified trials.

RESULTS AND CONCLUSIONS

Preterm infants with a birth weight of <800g are at risk of significant morbidity and mortality from PDA; it would be reasonable to treat them when symptomatic or if requiring positive pressure ventilator support. Those weighing >800g are unlikely to need treatment unless they are ventilator-dependent or show evidence of congestive heart failure.

Preterm infants who later require duct ligation show different vital signs and pH in early postnatal life

AIM

The study investigated early postnatal vital signs in very low birthweight (VLBW) infants who later developed patent ductus arteriosus (PDA). We hypothesised that the early postnatal course of vital signs and blood gas variables might differ between infants whose PDA closed spontaneously, those who responded to ibuprofen and those who later required PDA ligation.

METHODS

We analysed computerised records of VLBW infants born <28 weeks of gestational age, including vital signs, arterial pH values and echocardiographic data from the first postnatal days.

RESULTS

In total, 104 infants were included in the study. In the group of infants born <26 weeks of gestational age and requiring ibuprofen for PDA (n = 34), 12 infants ultimately required surgical ligation. Infants requiring ligation showed significantly lower oxygen saturation (p = 0.019), mean blood pressure (p = 0.034) and higher heart rate fluctuation ranges (p = 0.040) in the first five postnatal days than those who responded to ibuprofen. In multivariable logistic regression analysis, lower pH values in the first 48 h predicted the subsequent requirement for ligation independent of gestational age (p = 0.004).

CONCLUSION

Patients <26 weeks of gestational age requiring PDA ligation showed significant differences in the course of vital signs and pH during the first days of life.

Timing of pharmacological treatment for patent ductus arteriosus and risk of secondary surgery, death or bronchopulmonary dysplasia: a population-based cohort study of extremely preterm infants

BACKGROUND

The optimal timing of pharmacological treatment for patent ductus arteriosus (PDA) in extremely preterm infants is unknown.

OBJECTIVE

To investigate whether timing of pharmacological PDA treatment is associated with a risk of secondary PDA surgery or death before 3 months of age, or bronchopulmonary dysplasia (BPD) in extremely preterm infants.

METHODS

In this population-based cohort of infants born before 27 gestational weeks in Sweden in 2004-2007, 290/585 infants (50%) received pharmacological PDA treatment. Cox proportional hazards regression estimated the hazard ratio (HR, with 95% confidence interval, CI) of secondary PDA surgery or death as a composite outcome in relation to postnatal age at the start of pharmacological treatment: early (0-2 days); intermediate (3-6 days); late (≥7 days). Furthermore, the odds ratio (OR, with 95% CI) of BPD was estimated in relation to postnatal age at PDA treatment by conditional logistic regression.

RESULTS

The median postnatal age at the start of pharmacological PDA treatment was 4 days. 102 infants had secondary PDA surgery. Timing of PDA treatment was not associated with risk of PDA surgery or death; adjusted HRs were 0.89 (95% CI 0.57-1.39) after an intermediate start and 1.10 (95% CI 0.53-2.28) after a late start, compared to an early start of treatment. Compared to the early start of PDA treatment, the intermediate start was not associated with any risk of BPD, while late PDA treatment was associated with a lower BPD risk; adjusted ORs were 0.83 (95% CI 0.42-1.64) and 0.28 (95% CI 0.13-0.61), respectively.

CONCLUSION

Timing of pharmacological PDA treatment after extremely preterm birth is not associated with the risk of secondary PDA surgery or death. Moreover, expectant PDA management is not associated with an increased risk of BPD.

Limited effects of intravenous paracetamol on patent ductus arteriosus in very low birth weight infants with contraindications for ibuprofen or after ibuprofen failure

Finding the optimal pharmacological treatment of a patent ductus arteriosus (PDA) in preterm neonates remains challenging. There is a growing interest in paracetamol as a new drug for PDA closure. In this prospective observational cohort study, we evaluated the effectiveness of intravenous paracetamol in closing a PDA in very low birth weight infants with a hemodynamically significant PDA who either did not respond to ibuprofen or had a contraindication for ibuprofen. They received high-dose paracetamol therapy (15 mg/kg/6 h intravenous) for 3-7 days. Cardiac ultrasounds were performed before and 3 and 7 days after treatment. Thirty-three patients were included with a median gestational age of 25(1/7) weeks (IQR 1.66), a median birth weight of 750 g (IQR 327), and a median postnatal age of 14 days (IQR 12). Paracetamol was ineffective in 27/33 patients (82 %). Even more, after previous exposure to ibuprofen, this was even 100 %.

CONCLUSION

In this study, paracetamol after ibuprofen treatment failure was not effective for PDA closure in VLBW infants. From the findings of this study, paracetamol treatment for PDA closure cannot be recommended for infants with a postnatal age >2 weeks. Earlier treatment with paracetamol for PDA might be more effective.

Aminoglycoside-mediated relaxation of the ductus arteriosus in sepsis-associated PDA

Sepsis is strongly associated with patency of the ductus arteriosus (PDA) in critically ill newborns. Inflammation and the aminoglycoside antibiotics used to treat neonatal sepsis cause smooth muscle relaxation, but their contribution to PDA is unknown. We examined whether: 1) lipopolysaccharide (LPS) or inflammatory cytokines cause relaxation of the ex vivo mouse DA; 2) the aminoglycosides gentamicin, tobramycin, or amikacin causes DA relaxation; and 3) newborn infants treated with aminoglycosides have an increased risk of symptomatic PDA (sPDA). Changes in fetal mouse DA tone were measured by pressure myography in response to LPS, TNF-α, IFN-γ, macrophage-inflammatory protein 2, IL-15, IL-13, CXC chemokine ligand 12, or three aminoglycosides. A clinical database of inborn patients of all gestations was analyzed for association between sPDA and aminoglycoside treatment. Contrary to expectation, neither LPS nor any of the inflammatory mediators caused DA relaxation. However, each of the aminoglycosides caused concentration-dependent vasodilation in term and preterm mouse DAs. Pretreatment with indomethacin and N-(G)-nitro-L-arginine methyl ester did not prevent gentamicin-induced DA relaxation. Gentamicin-exposed DAs developed less oxygen-induced constriction than unexposed DAs. Among 488,349 infants who met the study criteria, 40,472 (8.3%) had sPDA. Confounder-adjusted odds of sPDA were higher in gentamicin-exposed infants, <25 wk and >32 wk. Together, these findings suggest that factors other than inflammation contribute to PDA. Aminoglycoside-induced vasorelaxation and inhibition of oxygen-induced DA constriction support the paradox that antibiotic treatment of sepsis may contribute to DA relaxation. This association was also found in newborn infants, suggesting that antibiotic selection may be an important consideration in efforts to reduce sepsis-associated PDA.

Efficacy of paracetamol for the treatment of patent ductus arteriosus in preterm neonates

Inhibitors of the cyclo-oxygenase component of prostaglandin-H₂ synthetase, namely indomethacin and ibuprofen, are commonly used in the treatment of hemodynamically significant patent ductus arteriosus. These drugs are associated with serious adverse events, including gastrointestinal perforation, renal failure and bleeding. The role of paracetamol, an inhibitor of the peroxidase component of prostaglandin-H₂ synthetase, has been proposed for the treatment of patent ductus arteriosus. We report a series of 8 neonates (birth weight: 724 ± 173 g; gestational age: 26 ± 2 weeks) treated with paracetamol for a hemodynamically significant patent ductus arteriosus, because of contraindications to ibuprofen or indomethacin. Successful closure was achieved in 6 out of 8 babies (75%). Median ductal diameter was significantly reduced after treatment (from 1.2 mm, range 1.0-2.5 mm to 0.6 mm, range 0.0-2.5 mm, p = 0.038). No adverse or side effects were observed during treatment. On the basis of these results, paracetamol could be considered a promising and safe therapy for the treatment of patent ductus arteriosus in neonates.

Failure of a repeat course of cyclooxygenase inhibitor to close a PDA is a risk factor for developing chronic lung disease in ELBW infants

BACKGROUND

The optimal treatment regimen or protocol for managing a persistent patent ductus arteriosus (PDA) in extremely low birth weight (ELBW) infants has not been well established. This study was aimed at evaluating the failure rate of a cyclooxygenase (COX) inhibitor (COI) for PDA closure and to determine the incidence of a PDA requiring ligation in ELBW infants. We examined the clinical characteristics and risk factors that may predict the clinical consequences of failure of PDA closure by COI.

METHODS

Medical information on 138 infants with birth weight (BW) < 1000 gm who survived for > 48 hours was retrieved. Clinical characteristics and outcomes of patients whose PDAs closed with COI were compared with those who did not close.

RESULTS

Of the 138 patients, 112 survived to discharge. Eighty (71.4%) of those who survived received 1-3 courses of COI treatment for a symptomatic PDA. A total of 32 (40%) failed COI treatment and underwent PDA ligation. Multivariable logistic regression analysis suggests that the observed differences in the outcomes in infants with or without symptomatic PDA can be explained by the babies with symptomatic PDA being more immature and sicker. No significant difference was seen in the incidence of chronic lung disease (CLD) in infants whose PDA was treated medically versus those who failed medical treatment and then underwent ligation. However, after adjusting for disease severity and other known risk factors, the odds ratio of developing CLD for surviving babies with a persistent PDA compared to those whose PDA was successfully closed with 1-2 courses of COI is 3.24 (1.07-9.81; p = 0.038).

CONCLUSIONS

When successfully treated, PDA in ELBW infants did not contribute significantly to the adverse outcomes such as CLD, retinopathy of prematurity (ROP) and age at discharge. This suggests that it is beneficial for a hemodynamically significant PDA to be closed. The failure of a repeat course of COI to close a PDA is a major risk factor for developing CLD in ELBW infants.

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

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

Interatrial defect and patent ductus arteriosus

We greatly appreciated the letter to the Editor by Rana Olgunturk and Serdar Kula. We can say that his interpretation coincides with our interpretation and with the knowledge about patent ductus arteriosus (PDA) and secundum atrial septal defects. Although functional closure of PDA usually occurs in the first few hours of life in healthy infants born at term (about 15 h of life in healthy infants born at term), true anatomic closure, in which the ductus loses the ability to reopen, may take several weeks. Persistent, patency for up to 10 days after birth is encountered in premature infants. The male Italian newborn infant of the cited case report was referred at the age of 2 days to the Cardiology Unit for a cardiovascular check-up (in the text: "in a 3-day-old newborn infant" must be comprehended as "in a 2-day-old newborn infant") and was mature. Interatrial septal shunts in newborns are frequently encountered. Since there are no definitive diagnostic criteria for both patent foramen ovale and secundum atrial septal defects, it is difficult to differentiate these two lesions by echocardiography, particularly in the early newborn period. Some authors, called these two lesions as "interatrial septal openings". The diagnosis, in the case report cited, was made not only on the basis of the first observation but also on the basis of the persistence of abnormalities during the long-term follow-up and therefore the infant was referred to a pediatric heart surgical unit were the abnormalities were confirmed.

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.

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

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