Relationship of Patent Ductus Arteriosus Size to Echocardiographic Markers of Shunt Volume

Echocardiographic evaluation of left atrial volume and comparative analysis to left atrial to aortic root ratio in premature neonates and infants with patent ductus arteriosus

PURPOSE

Left atrium to aortic root ratio (LA/Ao) is an echocardiographic marker of hemodynamically significant patent ductus arteriosus (PDA). Since 2-dimensional measurement of the ratio is geometrically limited, left atrial volume (LAV) which has 3-dimensional characteristics was investigated. The aim of this study was to determine a correlation between LA/Ao ratio and LAV as well as holodiastolic flow reversal in preterm neonates with and without a PDA.

METHODS

A retrospective evaluation of neonates with and without PDA was performed. Targeted neonatal echocardiography evaluation of LA/Ao and LAV was measured from parasternal long-axis view and the apical 4 and 2-chamber views, respectively. Univariate and linear regression analysis were performed.

RESULTS

200 patients were included of whom 158 (79.0%) had a PDA shunt. The median gestational age at the time of echo was 27.4 weeks (IQR: 25.7-29.4 weeks). The median LA/Ao ratio was 1.51 (IQR: 1.26-1.83) and median LAV indexed to weight was  .91 mL/kg (IQR: .65-1.18 mL/kg). There was a significant correlation between LA/Ao and LAV indexed to weight in the PDA group (r2 = .080, p = .0003). LA/Ao ratio and LAV indexed to weight differed significantly between those with diastolic flow reversal versus no-flow reversal (LA/Ao, p = .003; LAV, p = .001).

CONCLUSIONS

This study demonstrated a significant correlation between LA/Ao and LAV in preterm infants with PDA, with greater magnitude of discordance for LAV. The power of LAV versus LA/Ao in monitoring hemodynamically significant PDA requires prospective evaluation.

Selective early medical treatment of the patent ductus arteriosus in extremely low gestational age infants: a pilot randomised controlled trial protocol (SMART-PDA)

INTRODUCTION

Patent ductus arteriosus (PDA) is the most common cardiovascular problem that develops in extremely preterm infants and is associated with poor clinical outcomes. Uncertainty exists on whether early pharmacotherapeutic treatment of a clinically symptomatic and echocardiography-confirmed haemodynamically significant PDA in extremely preterm infants improves outcomes. Given the wide variation in the approach to PDA treatment in this gestational age (GA) group, a randomised trial design is essential to address the question. Before embarking on a large RCT in this vulnerable population, it is important to establish the feasibility of such a trial.

METHODS AND ANALYSIS

Design: a multi-centre, open-labelled, parallel-designed pilot randomised controlled trial. Participants: preterm infants born <26 weeks of gestation with a PDA diagnosed within 72 hours after birth. Intervention (selective early medical treatment (SMART) strategy): selective early pharmacological treatment of a moderate-severe PDA shunt (identified based on pre-defined clinical signs and routine screening echocardiography) within the first 72 postnatal hours with provision for repeat treatment if moderate-severe shunt persists. Comparison (early conservative management strategy): no treatment of PDA in the first postnatal week. Primary outcomes: (1) proportion of eligible infants recruited during the study period; (2) proportion of randomised infants treated outside of protocol-mandated therapy. Sites and sample size: the study is being conducted in seven neonatal intensive care units across Canada and the USA with a target of 100 randomised infants. Analysis: the primary feasibility outcomes will be expressed as proportions. A pre-planned Bayesian analysis will be conducted for secondary clinical outcomes such as mortality, severe intraventricular haemorrhage, procedural PDA closure and chronic lung disease to aid stakeholders including parent representatives decide on the appropriateness of enrolling this vulnerable population in a larger trial if the feasibility of recruitment in the pilot trial is established.

ETHICS AND DISSEMINATION

The study has been approved by the IWK Research Ethics Board (#1027298) and six additional participating sites. On the completion of the study, results will be presented at national and international meetings, published in peer-reviewed journals and incorporated into existing systematic reviews.

TRIAL REGISTRATION NUMBER

NCT05011149 (WHO Trial Registration Data Set in Appendix A).

PROTOCOL VERSION

Ver 7.2 (dated July 19, 2023).

Which left atrial volume measurement should we use in the neonatal intensive care?

BACKGROUND

Increased left atrial volume (LAV) is a marker of cardiovascular risk. Echocardiography standards to assess LAV in adults and children are the biplane area-length method (AL) and method of disks (MOD). LAV in neonatology is usually derived as M-mode ratio between the LA and the Aorta (LAAo). The aim of this study is to determine feasibility and reliability of these methods in neonatal clinical practice.

METHODS

Clinically indicated echocardiograms in neonatal intensive care patients were retrospectively analyzed. Feasibility was determined with an image quality score describing insonation angle, foreshortening and wall clarity. Reliability was determined with Bland-Altman and correlation coefficient analysis of intra- and inter-observer measurements.

RESULTS

104 infants ranging from 23 to 39 weeks gestation were included. The feasibility of LAAo, AL and MOD was comparable (median image score 4 out of 6 points). Linear regression between AL and MOD was excellent (R2 0.99). LAAo best-fit with MOD was reached with curve-linear regression (R2 0.28) whereby a LAAo of 1.60 correlated with 1.24 ml/kg, but with a wide 95 % CI. The correlation coefficient within and between observers for LAAo, biplane AL, biplane MOD and monoplane MOD was 0.93 (0.87-0.96), 0.98 (0.96-0.99), 0.98 (0.96-0.99), 0.99 (0.97-0.99) and 0.58 (0.11-0.81), 0.75 (0.44-0.89), 0.92 (0.88-0.98), 0.96 (0.88-0.98) respectively.

CONCLUSION

All methods were equally feasible and reliable when repeated by the same observer, but LAAo reliability was poor when repeated by a different observer. Biplane MOD was the most reliable and thus recommended in neonatal practice. Monoplane MOD performed well and could be considered as alternative but might be less accurate.

Targeted Neonatal Echocardiography in the Management of Neonatal Pulmonary Hypertension

Pulmonary hypertension (PH) in neonates, originating from a range of disease states with heterogeneous underlying pathophysiology, is associated with significant morbidity and mortality. Although the final common pathway is a state of high right ventricular afterload leading to compromised cardiac output, multiple hemodynamic phenotypes exist in acute and chronic PH, for which cardiorespiratory treatment strategies differ. Comprehensive appraisal of pulmonary pressure, pulmonary vascular resistance, cardiac function, pulmonary and systemic blood flow, and extrapulmonary shunts facilitates delivery of individualized cardiovascular therapies in affected newborns.

Clinical and echocardiography predictors of response to first-line acetaminophen treatment in preterm infants with hemodynamically significant patent ductus arteriosus

OBJECTIVE

To assess clinical and echocardiography predictors of acetaminophen response for the treatment of patent ductus arteriosus (PDA) in preterm neonates.

STUDY DESIGN

Retrospective cohort study of preterm infants born <30 weeks, with a diagnosis of hemodynamically significant PDA, who received 1st line treatment with intravenous acetaminophen during the first 2 postnatal weeks. Response was defined by PDA closure or improvement in PDA score of >50%.

RESULTS

A total of 100 infants were included whose median weight and gestational age at birth were 663 grams and 24.6 weeks respectively. In total, 66 infants were classified as responders and were more likely to have intrauterine growth restriction, exposure to maternal hypertension and chorioamnionitis. Non-response was more common among infants with thrombocytopenia and anemia.

CONCLUSION

Responders were more likely to be IUGR with echocardiography indices of lower preload. Response to 1st line intravenous acetaminophen therapy is comparable to non-steroidal drugs in preterm infants. Relationship of response to acetaminophen to perinatal characteristics requires further characterization.

Should we "eliminate" PDA shunt in preterm infants? A narrative review

The patent ductus arteriosus frequently poses a significant morbidity in preterm infants, subjecting their immature pulmonary vascular bed to substantial volume overload. This, in turn, results in concurrent hypoperfusion to post-ductal organs, and subsequently alters cerebral blood flow. In addition, treatment has not demonstrated definitive improvements in patient outcomes. Currently, the optimal approach remains a subject of considerable debate with ongoing research controversy regarding the best approach. This article provides a comprehensive review of existing literature.

The association between patterns of early respiratory disease and diastolic dysfunction in preterm infants

BACKGROUND

This study aims to determine the association between clinical patterns of early respiratory disease and diastolic dysfunction in preterm infants.

METHODS

Preterm infants <29 weeks' gestation underwent cardiac ultrasounds around day 7 and 14-21. Respiratory dysfunction patterns were classified as stable (ST), respiratory deterioration (RD) or early persistent respiratory dysfunction (EPRD) according to oxygen need. Diastolic dysfunction was diagnosed using a multi-parameter approach including left atrial strain (LASR) to help differentiate between cardiac or pulmonary pathophysiology.

RESULTS

98 infants (mean 27 weeks) were included. The prevalence of ST, RD and EPRD was 53%, 21% and 26% respectively. Diastolic dysfunction was more prevalent in the RD and EPRD groups with patent ductus arteriosus and significant growth restriction as risk factors. Not all infants with a PDA developed diastolic dysfunction. LASR was lower in the EPDR group.

CONCLUSION

Respiratory dysfunction patterns are associated with diastolic dysfunction in preterm infants.

Interventions for patent ductus arteriosus (PDA) in preterm infants: an overview of Cochrane Systematic Reviews

BACKGROUND

Patent ductus arteriosus (PDA) is associated with significant morbidity and mortality in preterm infants. Several non-pharmacological, pharmacological, and surgical approaches have been explored to prevent or treat a PDA.

OBJECTIVES

To summarise Cochrane Neonatal evidence on interventions (pharmacological or surgical) for the prevention of PDA and related complications, and interventions for the management of asymptomatic and symptomatic PDA in preterm infants.

METHODS

We searched the Cochrane Database of Systematic Reviews on 20 October 2022 for ongoing and published Cochrane Reviews on the prevention and treatment of PDA in preterm (< 37 weeks' gestation) or low birthweight (< 2500 g) infants. We included all published Cochrane Reviews assessing the following categories of interventions: pharmacological therapy using prostaglandin inhibitor drugs (indomethacin, ibuprofen, and acetaminophen), adjunctive pharmacological interventions, invasive PDA closure procedures, and non-pharmacological interventions. Two overview authors independently checked the eligibility of the reviews retrieved by the search, and extracted data from the included reviews using a predefined data extraction form. Any disagreements were resolved by discussion with a third overview author. Two overview authors independently assessed the methodological quality of the included reviews using the AMSTAR 2 (A MeaSurement Tool to Assess systematic Reviews) tool. We reported the GRADE certainty of evidence as assessed by the respective review authors using summary of findings tables.

MAIN RESULTS

We included 16 Cochrane Reviews, corresponding to 138 randomised clinical trials (RCT) and 11,856 preterm infants, on the prevention and treatment of PDA in preterm infants. One of the 16 reviews had no included studies, and therefore, did not contribute to the results. Six reviews reported on prophylactic interventions for the prevention of PDA and included pharmacological prophylaxis with prostaglandin inhibitor drugs, prophylactic surgical PDA ligation, and non-pharmacologic interventions (chest shielding during phototherapy and restriction of fluid intake); one review reported on the use of indomethacin for the management of asymptomatic PDA; nine reviews reported on interventions for the management of symptomatic PDA, and included pharmacotherapy with prostaglandin inhibitor drugs in various routes and dosages, surgical PDA ligation, and adjunct therapies (use of furosemide and dopamine in conjunction with indomethacin). The quality of reviews varied. Two reviews were assessed to be high quality, seven reviews were of moderate quality, five of low quality, while two reviews were deemed to be of critically low quality. For prevention of PDA, prophylactic indomethacin reduces severe intraventricular haemorrhage (IVH; relative risk (RR) 0.66, 95% confidence interval (CI) 0.53 to 0.82; 14 RCTs, 2588 infants), and the need for invasive PDA closure (RR 0.51, 95% CI 0.37 to 0.71; 8 RCTs, 1791 infants), but it does not appear to affect the composite outcome of death or moderate/severe neurodevelopmental disability (RR 1.02, 95% CI 0.90 to 1.15; 3 RCTs, 1491 infants). Prophylactic ibuprofen probably marginally reduces severe IVH (RR 0.67, 95% CI 0.45 to 1.00; 7 RCTs, 925 infants; moderate-certainty evidence), and the need for invasive PDA closure (RR 0.46, 95% CI 0.22 to 0.96; 7 RCTs, 925 infants; moderate-certainty evidence). The evidence is very uncertain on the effect of prophylactic acetaminophen on severe IVH (RR 1.09, 95% CI 0.07 to 16.39; 1 RCT, 48 infants). Necrotising enterocolitis (NEC) was lower with both prophylactic surgical ligation (RR 0.25, 95% CI 0.08 to 0.83; 1 RCT, 84 infants), and fluid restriction (RR 0.43, 95% CI 0.21 to 0.87; 4 RCTs, 526 infants). For treatment of asymptomatic PDA, indomethacin appears to reduce the development of symptomatic PDA post-treatment (RR 0.36, 95% CI 0.19 to 0.68; 3 RCTs, 97 infants; quality of source review: critically low). For treatment of symptomatic PDA, all available prostaglandin inhibitor drugs appear to be more effective in closing a PDA than placebo or no treatment (indomethacin: RR 0.30, 95% CI 0.23 to 0.38; 10 RCTs, 654 infants; high-certainty evidence; ibuprofen: RR 0.62, 95% CI 0.44 to 0.86; 2 RCTs, 206 infants; moderate-certainty evidence; early administration of acetaminophen: RR 0.35, 95% CI 0.23 to 0.53; 2 RCTs, 127 infants; low-certainty evidence). Oral ibuprofen appears to be more effective in PDA closure than intravenous (IV) ibuprofen (RR 0.38, 95% CI 0.26 to 0.56; 5 RCTs, 406 infants; moderate-certainty evidence). High-dose ibuprofen appears to be more effective in PDA closure than standard-dose ibuprofen (RR 0.37, 95% CI 0.22 to 0.61; 3 RCTs, 190 infants; moderate-certainty evidence). With respect to adverse outcomes, compared to indomethacin administration, NEC appears to be lower with ibuprofen (any route; RR 0.68, 95% CI 0.49 to 0.94; 18 RCTs, 1292 infants; moderate-certainty evidence), oral ibuprofen (RR 0.41, 95% CI 0.23 to 0.73; 7 RCTs, 249 infants; low-certainty evidence), and with acetaminophen (RR 0.42, 95% CI 0.19 to 0.96; 4 RCTs, 384 infants; low-certainty evidence). However, NEC appears to be increased with a prolonged course of indomethacin versus a shorter course (RR 1.87, 95% CI 1.07 to 3.27; 4 RCTs, 310 infants).

AUTHORS' CONCLUSIONS

This overview summarised the evidence from 16 Cochrane Reviews of RCTs regarding the effects of interventions for the prevention and treatment of PDA in preterm infants. Prophylactic indomethacin reduces severe IVH, but does not appear to affect the composite outcome of death or moderate/severe neurodevelopmental disability. Prophylactic ibuprofen probably marginally reduces severe IVH (moderate-certainty evidence), while the evidence is very uncertain on the effect of prophylactic acetaminophen on severe IVH. All available prostaglandin inhibitor drugs appear to be effective in symptomatic PDA closure compared to no treatment (high-certainty evidence for indomethacin; moderate-certainty evidence for ibuprofen; low-certainty evidence for early administration of acetaminophen). Oral ibuprofen appears to be more effective in PDA closure than IV ibuprofen (moderate-certainty evidence). High dose ibuprofen appears to be more effective in PDA closure than standard-dose ibuprofen (moderate-certainty evidence). There are currently two ongoing reviews, one on fluid restriction for symptomatic PDA, and the other on invasive management of PDA in preterm infants.

Delayed Surgical Closure of the Patent Ductus Arteriosus: Does the Brain Pay the Price?

OBJECTIVE

To investigate the relation between duration of hemodynamically significant patent ductus arteriosus (PDA), cerebral oxygenation, magnetic resonance imaging-determined brain growth, and 2-year neurodevelopmental outcome in a cohort of infants born preterm whose duct was closed surgically.

STUDY DESIGN

Infants born preterm at <30 weeks of gestational age who underwent surgical ductal closure between 2008 and 2018 (n = 106) were included in this observational study. Near infrared spectroscopy-monitored cerebral oxygen saturation during and up to 24 hours after ductal closure and a Bayley III developmental test at the corrected age of 2 years is the institutional standard of care for this patient group. Infants also had magnetic resonance imaging at term-equivalent age.

RESULTS

In total, 90 infants fulfilled the inclusion criteria (median [range]: 25.9 weeks [24.0-28.9]; 856 g [540-1350]. Days of a PDA ranged from 1 to 41. Multivariable linear regression analysis showed that duration of a PDA negatively influenced cerebellar growth and motor and cognitive outcome at 2 years of corrected age.

CONCLUSIONS

Prolonged duration of a PDA in this surgical cohort is associated with reduced cerebellar growth and suboptimal neurodevelopmental outcome.

Patent Ductus Arteriosus: A Contemporary Perspective for the Pediatric and Adult Cardiac Care Provider

The burden of patent ductus arteriosus (PDA) continues to be significant. In view of marked differences in preterm infants versus more mature, term counterparts (viewed on a continuum with adolescent and adult patients), mechanisms regulating ductal patency, genetic contributions, clinical consequences, and diagnostic and treatment thresholds are discussed separately, when appropriate. Among both preterm infants and older children and adults, a range of hemodynamic profiles highlighting the markedly variable consequences of the PDA are provided. In most contemporary settings, transcatheter closure is preferable over surgical ligation, but data on longer-term outcomes, particularly among preterm infants, are lacking. The present review provides recommendations to identify gaps in PDA diagnosis, management, and treatment on which subsequent research can be developed. Ultimately, the combination of refined diagnostic thresholds and expanded treatment options provides the best opportunities to address the burden of PDA. Although fundamental gaps remain unanswered, the present review provides pediatric and adult cardiac care providers with a contemporary framework in PDA care to support the practice of evidence-based medicine.

Single-dose prophylactic ibuprofen therapy for patent ductus arteriosus in preterm infants

This study aimed to evaluate the short-term morbidities and efficacy of single-dose prophylactic intravenous ibuprofen for patent ductus arteriosus (PDA) on the first day of life in preterm infants. Data of 69 preterm infants with birth weight < 1250 g and gestational age < 30 weeks admitted to the neonatal intensive care unit were analyzed. Of these, 37 infants were assigned to the prophylactic treatment (PT) group and 32 were assigned to the nonprophylactic treatment (non-PT) group. Only the PT group administered intravenous ibuprofen (10 mg/kg) once within 6 hours after birth. Until postnatal day 7, ductal closure occurred in 11 (34.4%) infants in the non-PT group, and in 35 (94.6%) infants in the PT group, of which 30 (81.1%) infants had ductal closure on postnatal day 1. There were 2 (5.4%) infants in the PT group and 9 (28.1%) in the non-PT group who needed ibuprofen treatment due to moderate-to-large PDA after postnatal day 7. Preterm infants in the PT group were less likely to develop an intraventricular hemorrhage (≥grade 2) (adjusted odds ratio 0.007, 95% confidence interval 0.01-0.45), had a shorter duration of invasive ventilatory support and central venous catheter, and earlier postnatal age to achieve feeding of 50 and 100 mL/kg/day compared with those in the non-PT group. Single-dose prophylactic intravenous ibuprofen on the first day of life decreased the occurrence of a persistent PDA and intraventricular hemorrhage (≥grade 2), and reduced the duration of invasive ventilatory support, central venous catheter use, and hospital stay.

Predictive Tool for Closure of Ductus Arteriosus with Pharmacologic or Surgical Treatment in Preterm Infants

To construct a model with the indices obtained by echocardiography to predict whether patent ductus arteriosus (PDA) was required to be treated with pharmacologic treatment or surgical ligation, we performed a prospective observational study, including all neonates with gestational age ≤ 30 weeks and assessed the hemodynamics of PDA by serial daily echocardiography examination at postnatal age of 0-12 h, 24 h, 48 h, and 72 h, respectively. The infants were classified in two groups based on whether they were treated with non-steroidal anti-inflammatory drugs (NSAIDs) and/or surgical ligation to close the PDA from the second week after birth. We compared the echocardiographic indices between the two groups and utilized the indices to construct a model to predict which premature infants' PDA requires intervention. The results showed that a total of forty-two preterm infants were enrolled in the study. 15 (35.7%) preterms were in the intervention group and 27 (64.3%) preterms were in the non-intervention group. Compared with the non-intervention group, the intervention group had a higher proportion of left ventricular volume overload and systemic shunt effect. In addition, the combined indicators of PDA size/weight > 3.2 mm/kg and LA/Ao > 1.4 at postnatal age of 72 h had a highest value to predict whether PDA requires intervention. These findings denoted that serial daily echocardiographic assessment can be useful in predicting whether a PDA will be closed with NSAIDs and/or surgical ligation in preterm infants with gestational age ≤ 30 weeks.Trial registration Number: IRB No. 2018-IRB-073. Date: 2018/09/21, retrospectively registered.

Relationship of Patent Ductus Arteriosus Echocardiographic Markers With Descending Aorta Diastolic Flow

OBJECTIVES

To characterize the relationship of echocardiographic markers of left heart overload and flow in peripheral major end-organ vessels (eg, celiac artery) with the presence of reversed holodiastolic flow in the descending aorta, considered a surrogate marker of an increased transductal shunt volume, in preterm patients with a patent ductus arteriosus (PDA).

METHODS

This work was a retrospective study of data from echocardiography performed to investigate the hemodynamic significance of a PDA in preterm patients. We studied differences in echocardiographic markers of the PDA shunt volume according to patterns of flow in the postductal descending aorta (no PDA, PDA with antegrade diastolic flow, and PDA with reversed diastolic flow). The strength of the association between each echocardiographic marker and the presence of aortic holodiastolic flow reversal was investigated.

RESULTS

We studied 137 patients with a median (interquartile range) birth weight of 850 (694-1030) g and a median gestational age of 25 (24-27) weeks. Among patients with a PDA (113), those with diastolic flow reversal in the descending aorta (44) presented had increased echocardiographic markers representative of the shunt volume (increased left ventricular output, left atrial-to-aortic ratio, pulmonary vein D wave, and shorter isovolumic relaxation time) compared to those with aortic antegrade diastolic flow. A positive, albeit weak, correlation between diastolic flow reversal and shunt volume echocardiographic markers was found. Abnormal diastolic flow in the celiac artery had the strongest correlation (R²  = 0.24).

CONCLUSIONS

In preterm patients with a PDA, echocardiographic markers of the shunt volume were more abnormal in patients with reversed diastolic flow in the descending aorta. These data support the assumption that variance in these markers are related to the shunt volume, which needs consideration when adjudicating hemodynamic significance.

BPD treatments: The never-ending smorgasbord

Despite important advances in neonatal care, rates of bronchopulmonary dysplasia (BPD) have remained persistently high. Numerous drugs and ventilator strategies are used for the prevention and treatment of BPD. Some, such as exogenous surfactant, volume targeted ventilation, caffeine, and non-invasive respiratory support, are associated with modest but important reductions in rates of BPD and long-term respiratory morbidities. Many other therapies, such as corticosteroids, diuretics, nitric oxide, bronchodilators and anti-reflux medications, are widely used despite conflicting, limited or no evidence of efficacy and safety. This paper examines the range of therapies used for the prevention or treatment of BPD. They are classified into those supported by evidence of effectiveness, and those which are widely used despite limited evidence or unclear risk to benefit ratios. Finally, the paper explores emerging therapies and approaches which aim to prevent or reduce BPD and long-term respiratory morbidity.

Early Role of the Atrial-Level Communication in Premature Infants with Patent Ductus Arteriosus

BACKGROUND

High-volume systemic-to-pulmonary ductus arteriosus shunts in premature infants are associated with adverse neonatal outcomes. The role of an atrial communication (AC) in modulating the effects of a presumed hemodynamically significant patent ductus arteriosus (PDA) is poorly studied. The objective of this study was to characterize the relationship between early AC and echocardiographic indices of PDA shunt volume and clinical neonatal outcomes.

METHODS

A retrospective review of preterm infants (born at <32 weeks' gestation) who underwent echocardiography in the first postnatal week was performed. The cohort was divided into four groups on the basis of presence of a presumed hemodynamically significant PDA (≥1.5 vs <1.5 mm) and AC size (≤1 vs >1 mm), and echocardiographic measures of PDA shunt volume were then compared. Clinical outcomes, including chronic lung disease and intraventricular hemorrhage, were also compared among all four groups.

RESULTS

A total of 199 preterm infants (mean birth weight, 928 ± 632 g; mean gestational age, 26.6 ± 1.5 weeks) were identified; 159 infants had PDAs ≥ 1.5 mm, of whom 52 had ACs ≤ 1 mm and 107 had ACs > 1 mm. The remaining 40 infants had PDAs < 1.5 mm, of whom 23 had ACs ≤ 1 mm and 17 had ACs > 1 mm. Infants with PDAs ≥ 1.5 mm and ACs > 1 mm had higher pulmonary vein D-wave velocities (P < .05), higher left ventricular output (P < .005), higher PDA scores (P < .001), and increased rates of reversed diastolic flow in the descending aorta (P < .001), celiac artery (P < .001), and middle cerebral artery (P < .001) than infants with either PDAs < 1.5 mm or PDAs ≥ 1.5 mm and ACs ≤ 1 mm. There was no difference in the incidence of intraventricular hemorrhage, but infants with PDAs ≥ 1.5 mm and ACs > 1 mm had a higher risk for a composite outcome of chronic lung disease or death before hospital discharge (P < .05).

CONCLUSIONS

Echocardiographic evidence of ACs > 1 mm in patients with PDAs ≥ 1.5 mm during the first postnatal week may be a marker of a more pathologic hemodynamically significant PDA in premature infants. Future investigations should evaluate if early identification and treatment of patients with both high-volume PDAs and larger atrial-level communications may help mitigate adverse outcomes, such as chronic lung disease or death, in this high-risk patient population.

Pulmonary hypertension is an important co-morbidity in developmental lung diseases of infancy: Bronchopulmonary dysplasia and congenital diaphragmatic hernia

Bronchopulmonary dysplasia (BPD) following preterm birth and congenital diaphragmatic hernia (CDH) are both forms of developmental lung disease that may result in persistent pulmonary and pulmonary vascular morbidity in childhood. The pulmonary vascular disease (PVD) which accompanies BPD and CDH is due to developmental abnormalities and ongoing perinatal insults. This may be accompanied by evidence of elevated right heart pressures and pulmonary vascular resistance, leading to diagnosis of pulmonary hypertension (PH). The development of PH in these conditions is associated with increased morbidity and mortality in the vulnerable BPD and CDH populations. We present a review of PVD pathogenesis and evaluation in BPD and CDH and discuss management of related sequelae of PH co-morbidity for affected infants.

Size of Patent Ductus Arteriosus and Echocardiographic Markers of Shunt Volume in Preterm Infants Based on Postnatal Age

Objective: This study was conducted in order to compare the strength of correlation between echocardiographic markers of shunt volume and patent ductus arteriosus (PDA) diameter based on postnatal age. Methods: This retrospective study focused on preterm infants (aged <32 weeks of gestation) admitted to the Neonatal Intensive Care Unit of Korea University Ansan Hospital, between April 2014 and December 2017, who studied serial targeted neonatal echocardiography (TNE) for PDA during hospitalization. The association between echocardiographic characteristics and duct size was divided into the following days: within 3 days (very early, VE), 4-7 days after birth (early, E), and after 8 days of birth (late, L). Results: We found 113 assessments conducted on 57 infants in the VE period, 92 assessments on 40 infants in the E period, and 342 assessments on 37 infants in the L period. Median gestational age and birth weight were 28⁺² weeks of gestation and 1,115 g, respectively. In the univariate regression analysis, we found a statistically significant correlation between PDA diameter and all TNE markers in the E and L days, but not in the VE period. Only ductal velocity [coefficient of determination (R ²) = 0.224], antegrade left pulmonary artery diastolic flow velocity (R ² = 0.165), left ventricular output (LVO)/superior vena cava (SVC) flow ratio (R ² = 0.048), and E/A wave ratio (R ² = 0.092) showed weak correlations with PDA diameter in the VE period. The slopes of the regressions showed significant changes based on postnatal age in the maximum ductal velocity, left atrium/aorta ratio, LVO/SVC flow ratio, and LVO. Conclusions: It is difficult to predict the echocardiographic markers of shunt volume based on the PDA diameter in preterm infants younger than 4 days. A better understanding of the changes in the hemodynamic consequences of PDA based on postnatal age is needed when considering treatment.

Anatomic Concordance of Neonatologist-Performed Echocardiography as Part of Hemodynamics Consultation and Pediatric Cardiology

BACKGROUND

Targeted neonatal echocardiography (TnECHO) performed by neonatologists as part of a hemodynamics consultation is increasingly being used in neonatal intensive care units. To minimize delays in obtaining physiologic data, first echocardiograms may be obtained by the neonatal hemodynamics team and reviewed afterward by a pediatric cardiologist. This practice has not been systematically evaluated. The aim of this study was to compare concordance between anatomic findings on TnECHO and pediatric cardiology reports.

METHODS

This was a retrospective evaluation of 339 infants at low risk for congenital heart disease (CHD) admitted to two large referral centers with established neonatal hemodynamics programs who underwent comprehensive TnECHO as their first postnatal echocardiographic examinations. The protocol included comprehensive imaging of intracardiac anatomy, outflow tract concordance and integrity, aortic arch anatomy, pulmonary vein location and flow, and transitional shunts. The hemodynamics consultation note was compared with the cardiology report to determine anatomic concordance or major or minor discrepancies in all first studies.

RESULTS

Anatomic concordance occurred in 97.9% (κ = 0.862; 95% CI, 0.762-0.962; P < .001). There were seven minor discrepancies (small muscular ventricular septal defects and coronary fistulas). The index population included 23 infants (6.7%) with CHD, of whom only one (0.3%) had a ductal-dependent lesion (coarctation of the aorta) which was correctly identified by both teams.

CONCLUSIONS

The rate of major CHD in patients considered eligible for hemodynamics consultation was low, and there was high diagnostic concordance between trained neonatal hemodynamics specialists and pediatric cardiology. First echocardiograms obtained by subspecialty neonatologists may provide imaging of sufficient quality to evaluate a critically unwell neonate with low suspicion for critical CHD lesions. These results should not be extrapolated to infants in whom CHD is suspected. This study highlights the importance of formalized, rigorous, and standardized training for neonatologists with hemodynamics expertise who perform timely assessments using TnECHO.

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

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

Patent Ductus Arteriosus-Time for a Definitive Trial

More than 70 randomized controlled trials have been conducted on the management of patent ductus arteriosus (PDA) in preterm infants. Yet, clinicians are unsure if treating a PDA improves clinically important outcomes. Earlier clinical trials have primarily explored which pharmacotherapeutic agent effectively closes the PDA. Because many of these trials included older infants, had widely varying PDA definitions, and provided open-label treatment, it is difficult to draw inferences on clinical outcomes based on the results of these trials. These flaws in trial design might have contributed to the growing notion that "no treatment" is a feasible option irrespective of the clinical characteristics of the infant and the PDA shunt volume.

Serial Doppler velocimetry of mesenteric and portal flow in very-low-birth-weight preterm neonates with and without patent ductus arteriosus

BACKGROUND

Very-low-birth-weight (VLBW) preterm neonates are vulnerable to patent ductus arteriosus (PDA), which might be related to high-resistance flow in the superior mesenteric artery (SMA), with decreased diastolic flow in situations of marked intestinal hypoperfusion. No previous studies have evaluated the portal vein and superior mesenteric vein (SMV) parameters to assess the PDA hemodynamic repercussions.

OBJECTIVE

To assess mesenteric and portal flow in VLBW preterm neonates with or without PDA using serial Doppler ultrasonography (US).

MATERIALS AND METHODS

We conducted a prospective longitudinal study on 61 VLBW preterm neonates submitted to 161 Doppler US exams, from 2 days to 20 days of age.

RESULTS

All infants exhibited a progressive daily increase in the mean of the SMA diameter and systolic velocity, the portal vein diameter, the peak velocity, the mean velocity and the flow volume and of SMV diameter (P<0.05). The incidence of PDA was 37.7% (n=23) and infants with the disease revealed a smaller diameter, greater systolic velocity, lower diastolic velocity, and higher resistivity and pulsatility indices on SMA compared to those without PDA (P<0.05). Additionally, 47.8% (n=11) of infants with PDA exhibited absent or reversed end-diastolic flow in the SMA, and its resolution was seen among 54.5% (n=6) of these. Infants with PDA also exhibited lower values of portal vein diameter and flow volume and of SMV diameter (P<0.01).

CONCLUSION

Doppler US enhances the understanding of mesenteric and portal flow, including the effects of PDA. The study of SMV and portal vein flow is proposed as a new parameter in PDA evaluation.

Toward rational management of patent ductus arteriosus: ductal disease staging and first line paracetamol

Aims: To study paracetamol (PCM) use as first line therapy for significant patent ductus arteriosus (sPDA) closure, stratified by echocardiography.Methods: In this retrospective observational study, a prepublished score comprising PDA size and velocity, PDA:left pulmonary artery ratio, diastolic flow in main and LPA, LA:Ao ratio and left ventricular:aortic ratio were included for shunt severity. Successful closure was defined a priori as closure or ≥50% reduction in score. Comparisons were made between infants with sPDA who were treated and not treated.Results: During November 2017-2018, 227 infants from 23 to 31⁺⁶ weeks' gestational age (GA) were admitted; 50 (22%) infants were diagnosed with PDA, 32 treated with PCM, overall treatment rate of 32/227 (14%). Successful therapy was noted in 23/32 (72%) and was higher when treated at ≤7 days (80 versus 68%, p = .68), in infants >26 weeks GA (62.5 versus 100%, p = .07) and BW >1000 g (65.4 versus 100%, p = .14). Univariate analysis noted statistical significance only for GA. Eighteen infants were managed conservatively. Treated infants had a lower GA and BW, higher composite ECHO score (14.4 ± 0.5 versus 19 ± 0.4, p < .001).Conclusions: Composite scoring helped reduce exposure, and focus more on infants with lower GA and BW with greater shunt severity.

Predictors of Early Extubation after Patent Ductus Arteriosus Ligation among Infants Born Extremely Preterm Dependent on Mechanical Ventilation

We conducted a retrospective study of 166 ventilator-dependent neonates born extremely preterm in whom patent ductus arteriosus was surgically ligated and evaluated the association of preoperative characteristics and time-to-successful postoperative extubation. Larger patent ductus arteriosus diameter ([>2.5 mm], adjusted hazard ratio 0.51, 95% CI 0.36-0.72) and left-ventricular dilatation (z score ≥2, adjusted hazard ratio 0.61, 95% CI 0.42-0.87) were associated with earlier extubation.

Patent ductus arteriosus in preterm infants: is early transcatheter closure a paradigm shift?

The optimal management approach of the patent ductus arteriosus (PDA) in premature infants remains uncertain owing the lack of evidence for long-term benefits and the limited analyses of the complications of medical and surgical interventions to date. In recent years, devices suitable to plug the PDA of premature infants (including extremely low birthweight, <1000 g) have become available and several trials have demonstrated successful and safe transcatheter PDA closure (TCPC) in this population. Whether TCPC represents a paradigm shift in PDA management that will result in improved short- and long-term outcomes, less bronchopulmonary dysplasia, improved neurodevelopment, or better long term renal function remains to be seen. Careful rigorous study of the potential benefits of TCPC in this highly vulnerable population in the context of well-designed adequately powered trials is needed prior to widespread adoption of this approach.

Ductal size indexed to weight and body surface area correlates with morbidities in preterm infants ≤32 weeks

OBJECTIVES

To assess ductal size correlated to spontaneous closure, pharmacological or surgical treatment; to index ductal diameter to body weight and body surface area; to evaluate the morbidities.

STUDY DESIGN

Retrospective study on preterms ≤32 weeks, birth weight ≤1500 g, extremely low birth weight (ELBW) and very low birth weight (VLBW). Inclusion criteria: patent ductus arteriosus (PDA) with a diameter ≥1 millimeter (mm) at 72 h from birth; need for ibuprofen treatment on the basis of a hemodynamically significant ductus arteriosus (HsPDA).

RESULTS

One hundred infants with the diagnosis of PDA have been included. We observed a prevalence of spontaneous closure in 34% of newborns (41.3% VLBW versus 26.7% ELBW). The percentage of response to a single course of ibuprofen was of 62% (68.5% ELBW versus 54.3% VLBW). The mean of absolute ductal diameter was of 2.26 ± 0.62 mm in ELBW and 2.18 ± 0.42 mm in VLBW. The indexing of ductus size to body weight demonstrated a higher value in ELBW than VLBW (2.76 ± 0.97 mm/kg versus 1.84 ± 0.40 mm/kg).

CONCLUSIONS

Our results confirmed that HsPDA can develop in presence of a ductus >1.5 mm as absolute value or >1.4 mm/kg as indexed to body weight. In ELBW infants the ductal size indexed for body weight and body surface area could be more predictive of spontaneous closure or need for pharmacological treatment compared to the absolute value of ductal size. A strong association between HsPDA and short- or long-term morbidities was confirmed particularly in ELBW.

Ibuprofen treatment after the first days of life in preterm neonates with patent ductus arteriosus

AIM

Patent ductus arteriosus (PDA) is treated with ibuprofen and it is known that the clearance of ibuprofen increases with postnatal age. We aimed to study whether postnatal age-adjusted ibuprofen dosages improve the effectiveness of treatment compared to standard ibuprofen dosages after the first days of life.

METHODS

A historical cohort of 207 preterm neonates treated with standard ibuprofen dosages (Group A; 2011-2015) was compared to a prospective cohort of 66 preterm neonates treated with postnatal age-adjusted ibuprofen dosages (Group B; 2015-2016).

RESULTS

Both groups had comparable background characteristics. Treatment was started after median 6 (25-75th percentile: 4-11) and 5 (25-75th percentile: 4-11) days and effectiveness was 33.2 and 44.7% (p = .17) in groups A and B, respectively. No hemodynamically significant PDA was found in 23/49 (46.9%) of the patients born before 28 weeks after adjusted ibuprofen dosages compared to 48/162 (29.6%) after standard ibuprofen dosages (p = .04). There were significantly more reversible side effects with the postnatal age-adjusted ibuprofen dosages (p = .04).

CONCLUSIONS

There seems to be a trend to higher effectiveness with the adjusted ibuprofen dosages in preterm neonates before 28 weeks, but it is associated with more reversible side effects.