Patent ductus arteriosus in preterm infants

Educational Impact of Targeted Neonatal Echocardiography and Hemodynamics Programs on Neonatal-Perinatal Medicine Fellows

OBJECTIVE

 Targeted neonatal echocardiography (TNE) is a real-time cardiac imaging modality used by a hemodynamics program to aid in diagnosis, treatment, and monitoring of neonatal cardiovascular illness. This study aimed to describe trainees' perspectives on existing hemodynamics education and perceived impacts of TNE and hemodynamics services on their education.

STUDY DESIGN

 This was a mixed quantitative and qualitative study that surveyed neonatal-perinatal medicine (NPM) fellow trainees in Canada and the United States, at programs both with and without a hemodynamics service.

RESULTS

 Ninety-two fellows responded to the survey, of whom 24 (26%) were enrolled in a program with an active hemodynamics service, 64 (70%) were training at a program without a hemodynamics service, and 4 (4%) were unsure. Trainees at centers with a hemodynamics service were more satisfied with their cardiovascular physiology education (91 vs. 69%, p = 0.040). Twenty-five percent of all trainees felt they do not have sufficient hemodynamics training to prepare them for independent practice. Areas of knowledge gaps were identified. Bedside teaching combined with didactic teaching was identified as useful means of teaching.

CONCLUSION

 Most trainees believed that TNE and a hemodynamics service are valuable educational assets. Thoughtful curriculum design for real-time and consolidation learning, with specific emphasis on content gaps, should be considered.

KEY POINTS

· NPM Fellows perceive TNE & Neonatal Hemodynamics service as a valuable educational opportunity.. · Incorporation of TNE/Hemodynamics teaching into NPM curriculum can enrich trainee experience.. · Combining bedside and classroom teaching is key to successful cardiovascular training..

Low dose paracetamol for management of patent ductus arteriosus in very preterm infants: a randomised non-inferiority trial

OBJECTIVE

To compare the efficacy of low dose-short course intravenous paracetamol with a conventional dose regimen for early targeted closure of patent ductus arteriosus (PDA).

DESIGN

Single-centre, double-blinded, active controlled, randomised non-inferiority trial.

SETTING

Level III neonatal intensive care unit in Western India.

PATIENTS

Preterm infants <30 weeks of gestation requiring mechanical ventilation, or continuous positive airway pressure with FiO₂ ≥0.35 and diagnosed with a haemodynamically significant PDA (hsPDA) at 18-24 hours of postnatal age.

INTERVENTIONS

Low dose (10 mg/kg/dose 6 hourly for 72 hours) versus conventional dose (15 mg/kg/dose 6 hourly for 120 hours) intravenous paracetamol treatment.

MAIN OUTCOME MEASURES

Comparison of the rates of ductal closure at completion of sixth postnatal day, using a prespecified non-inferiority margin of 20%.

RESULTS

A total of 102 infants were enrolled. The median gestational age and birth weight of the included infants were 26.4 weeks and 830 g. At completion of the sixth postnatal day, closure of PDA was achieved in 92% of infants in the low dose group as compared with 94% of those in the standard dose group (risk difference: -1.6%, 95% CI: -11.6% to 8.5%, p=0.38). The rates of rescue therapies, adverse effects and other neonatal morbidities were comparable in both groups.

CONCLUSION

In very preterm infants on significant respiratory support, low dose-short course intravenous paracetamol treatment was non-inferior to a conventional dosing regime of paracetamol for closure of hsPDA in the first week of postnatal age. Larger studies with narrow margins of non-inferiority are required to confirm our findings.

TRIAL REGISTRATION NUMBER

CTRI/2017/10/010012.

Early prediction of a significant patent ductus arteriosus in infants <32 weeks gestational age

BACKGROUND

The optimal thresholds for identification of preterm infants at greatest risk for adverse sequelae related to patent ductus arteriosus have not been well delineated. Our aim was to determine hemodynamic parameters in the first 24 hours using continuous non-invasive vital and structural measurements to predict which infants required PDA treatment in our institution.

METHODS

Retrospective secondary analysis of data from infants born 23 to 32 weeks gestational age with cardiac output and stroke volume via electrical cardiometry, cerebral tissue oximetry measurements, mean arterial blood pressure (BP), heart rate, and oxygen saturation and functional echocardiography results at 12 hours of life were recorded when available (93 percent of subjects).

RESULTS

A total of 292 infants, of which 55 (26±2 weeks, 862±268 grams) were treated for PDA. Treated infants demonstrated increased left ventricular output (p < 0.001) and lower mean BP (p = 0.010). The optimal area under the receiver operating characteristic curve (AUC) for predicting PDA treatment in our all gestations cohort is a mean BP at 15 hours of life of <33 mm Hg (AUC = 0.854, p < 0.001, 95% CI 0.792, 0.916). For infants <28 weeks a mean BP at 13 hours of life of <33 mm Hg (AUC = 0.741, p < 0.050, 95% CI 0.642, 0.839).

CONCLUSIONS

In our cohort increased left ventricular output and lower mean BP predicted a clinically significant PDA requiring treatment.

Effects of antenatal indomethacin on ductus arteriosus early closure and on adverse outcomes in preterm neonates

Introduction: Premature birth is a leading cause of neonatal morbidity and mortality. Since gestational age at birth is the most important predictive factor of adverse neonatal outcomes, strategies to postpone premature labor are of major importance. Studies on tocolytic drugs show that COX inhibitors such as indomethacin are superior to others in terms of efficiency in delaying birth, but results concerning neonatal outcomes associated with prenatal exposure to these drugs show controversial results. Indomethacin is also used in the postnatal age for pharmacologic treatment of patent ductus arteriosus (PDA), but no data concerning the effects of antenatal exposure on postnatal ductal patency are available.Methods: In this study, we focused primarily on the association between antenatal indomethacin (AI) and postnatal patency of ductus arteriosus while our secondary aim was to highlight any possible influence of AI exposure on adverse neonatal outcomes. We performed a retrospective analysis of 241 medical records of newborns born before 33 weeks' gestation and exposed to antenatal tocolysis. Obstetrical data and neonatal outcomes of newborns exposed to AI were compared to those of neonates exposed to other tocolytic drugs. Early ductal closure (EDC) was defined when functional echocardiography performed within 24 hours of life showed a closed duct. Occurrence of intraventricular hemorrhage (IVH), periventricular leukomalacia (PVL), respiratory distress syndrome (RDS), chronic lung disease (CLD), necrotizing enterocolitis (NEC), sepsis, and PDA were compared between the groups and the diagnosis of at least one of III-IV grade IVH, PVL, CLD, sepsis, surgical NEC, or death was defined as a severe outcome.Results: The univariate analysis showed that infants in the AI group were at a higher risk of IVH, CLD, RDS, sepsis, and PDA. The incidence of severe outcomes also appeared to be higher in this group, while no effect of AI on PDA was observed. Since we noticed that infants exposed to AI had a lower gestational age and worse clinical conditions at birth when compared to the controls, we considered this as a confounding factor. To overcome this bias, we performed a multivariate analysis that evidenced no significant role of AI on the occurrence of severe outcomes. On the other hand, a possible association was confirmed for all degrees of IVH (OR: 3.16, 95% CI : [1.41; 7.05]) and sepsis (OR: 2.81, 95% CI: [1.24; 6,28]).Conclusions: The unexpected result shown by the multivariate analysis was the association between AI exposure and EDC (OR: 2.52, 95% CI: [1.02; 6.21]). This result, which has never been evidenced in previous studies, has great clinical importance. It is well known that PDA is more frequent at lower gestational ages, thus reducing the incidence of PDA could lead to an improvement of overall outcomes in extremely preterm newborns.

Cerebral oxygenation and echocardiographic parameters in preterm neonates with a patent ductus arteriosus: an observational study

BACKGROUND

A haemodynamically significant patent ductus arteriosus (hsPDA) is clinically suspected and confirmed by echocardiographic examination. A hsPDA decreases cerebral blood flow and oxygen saturation by the ductal steal phenomenon.

AIM

To determine the relationship between echocardiographic parameters, cerebral oxygenation and a hsPDA in preterm infants.

METHODS

380 preterm infants (<32 weeks gestational age) born between 2008 and 2010 were included. Blinded echocardiographic examination was performed on the second, fourth and sixth day after birth. Examinations were deblinded when hsPDA was clinically suspected. Regional cerebral oxygen saturation (rScO₂) was continuously monitored by near-infrared spectroscopy during 72 h after birth, and afterwards for at least 1 h before echocardiography. Echocardiographic parameters included ductal diameter, end-diastolic flow in the left pulmonary artery, left atrium/aorta ratio and ductal flow pattern.

RESULTS

rScO₂ was significantly related only to ductal diameter over time. Mixed modelling analysed the course of rScO₂ over time, where infants were divided into four groups: a closed duct, an open haemodynamically insignificant duct (non-sPDA), a hsPDA, which was successfully closed during study period (SC hsPDA) or a hsPDA, which was unsuccessfully closed during study period (UC hsPDA). SC hsPDA infants showed the highest rScO₂ on day 6, while UC hsPDA infants had the lowest rScO₂ values.

CONCLUSIONS

Ductal diameter is the only echocardiographic parameter significantly related to cerebral oxygenation over time. Cerebral oxygenation takes a different course over time depending on the status of the duct. Low cerebral oxygenation may be suggestive of a hsPDA.

Diagnosing significant PDA using natriuretic peptides in preterm neonates: a systematic review

BACKGROUND AND OBJECTIVES

Echocardiogram is the gold standard for the diagnosis of hemodynamically significant patent ductus arteriosus (hsPDA) in preterm neonates. A simple blood assay for brain natriuretic peptide (BNP) or amino-terminal pro-B-type natriuretic peptide (NT-proBNP) may be useful in the diagnosis and management of hsPDA. Our objectives were to determine the diagnostic accuracy of BNP and NT-proBNP for hsPDA in preterm neonates and to explore heterogeneity by analyzing subgroups.

METHODS

The systematic review was performed as recommended by the Cochrane Diagnostic Test Accuracy Working Group. Electronic databases, conference abstracts, and cross-references were searched. We included studies that evaluated BNP or NT-proBNP (index test) in preterm neonates with suspected hsPDA (participants) in comparison with echocardiogram (reference standard). A bivariate random effects model was used for meta-analysis, and summary receiver operating characteristic curves were generated.

RESULTS

Ten BNP and 11 NT-proBNP studies were included. Studies varied by methodological quality, type of commercial assay, thresholds, age at testing, gestational age, and whether the assay was used to initiate medical or surgical therapy. Sensitivity and specificity for BNP at summary point were 88% and 92%, respectively, and for NT-proBNP they were 90% and 84%, respectively.

CONCLUSIONS

The studies evaluating the diagnostic accuracy of BNP and NT-proBNP for hsPDA varied widely by assay characteristics (assay kit and threshold) and patient characteristics (gestational and chronological age); therefore, generalizability between centers is not possible. We recommend that BNP or NT-proBNP assays be locally validated for specific patient population and outcomes, to initiate therapy or follow response to therapy.

The Association between Patent Ductus Arteriosus and Perinatal Infection in A Group of Low Birth Weight Preterm Infants

OBJECTIVE

Patent ductus arteriosus (PDA) is an extremely common occurrence in very premature infants. Untreated symptomatic PDA may be associated with chronic lung disease. PDA has a major role in neonatal mortality and morbidity. We compared the efficacy and safety of oral versus intravenous ibuprofen for the pharmacological closure of PDA in low birth weight (LBW) preterm infants.

METHODS

A randomized, single-blinded, controlled study was performed on premature neonates at the neonatal unit, University Hospital for Obstetrics and Gynecology "Koço Gliozheni", Tirana, Albania from January 2010 to December 2012. The study enrolled 68 preterm infants with a confirmed and significant PDA. The preterm infants received either intravenous or oral ibuprofen randomly as an initial dose of 10 mg/kg, followed by 5 mg/kg at 24 and 48 h. Findings : 36 patients were treated with oral ibuprofen and 32 with intravenous ibuprofen during this period. After the first course of the treatment, the PDA closed in 30 (83.3%) of the patients assigned to the oral ibuprofen group versus 23 (71.8%) of those enrolled in the intravenous ibuprofen group (P=0.355). 15 patiens needed a second treatment course and they all (100%) had clinical signs of infection and positive blood culture. There was no reopening of the ductus after the closure.

CONCLUSION

Our data indicate that, for LBW infants, the rate of early ductal closure was comparable and the adverse effects were fewer with oral ibuprofen in comparison to the intravenous route. Association of PDA with perinatal infection has a negative impact in pharmacological closure of the ductus, increasing the need for a second course of treatment or for surgery.

B-type natriuretic peptide for assessment of haemodynamically significant patent ductus arteriosus in premature infants

Aim: Haemodynamically significant patent ductus arteriosus (hsPDA) is frequently observed in premature infants. This study was conducted to explore whether the blood BNP can be a valuable biomarker to assess the necessity of treatment for hsPDA in premature infants.

Methods: Serial measurements of the blood BNP were performed during the first 5 days of life in premature infants with hsPDA (Group I) and those without hsPDA (Group N). The definition of the hsPDA was the PDA requiring treatment, such as indomethacin administration and/or surgical ligation.

Results: Forty-six subjects were enrolled. Compared with Group N, Group I showed significantly higher level of blood BNP at postnatal 24–96 h and demonstrated the peak value at postnatal 24–48 h. With the ROC curve using the data at postnatal 24–48 h in Group I, we deduced the predictive value of 250 pg/mL of blood BNP for indomethacin treatment. Similarly, with the ROC curve using the maximal value of blood BNP within the first 5 days of life, the predictive value of 2000 pg/mL for surgical ligation was deduced.

Conclusions: Blood BNP during early postnatal period can be a useful biomarker to assess the necessity of treatment for hsPDA in premature infants.

Clinical pharmacological studies in children: From exploratory towards confirmation driven methodology

Just like children are not small adults, pediatric studies are not just subgroup-adult studies. Clinical pharmacology aims to predict these effects based on drug, population and/or patient-specific pharmacokinetics (concentration-time profiles) and -dynamics (concentration-effect profile). The most essential characteristics of childhood are growth and maturation. Both phenomena are most prominent during infancy making the claim that “an infant is not just a small child” as relevant compared to the paradigm that “a child is not just a small adult”. From a clinical pharmacology perspective, the consequence of such a dynamic setting is extensive variability throughout childhood in both the pharmacokinetics and pharmacodynamics. Trial design probably has impact on recruitment to an even greater extent compared to adult studies. In general, if a study is designed well, with a clear clinical question with which parents and children can identify, they are likely to consider participation. Open communication with all stakeholders involved will most likely result in ethically correct, practically feasible, scientifically sound, and economical reasonable studies to provide children with the appropriate treatment. From an academic perspective, feasibility, relevance, applicability and costs of clinical pharmacological studies in children can be significantly improved by new sampling concepts (e.g., saliva, urine, dried spot blood) and the systematic introduction of already known information into the trial design through model based pediatric drug development, that mainly affect feasibility of pharmacokinetic studies. In contrast, for the pharmacodynamic part of pediatric studies, development and validation of population specific biomarkers or robust outcome variables is urgently needed.