Hey, Doctor, Leave the PDA Alone

Patent Ductus Arteriosus Occlusion in Premature Infants

Transcatheter ductal closure has proven to be safe and effective to occlude the patent ductus arteriosus (PDA) in premature infants. We have developed a robust multidisciplinary PDA program. After gaining experience performing transcatheter ductal closure in the cardiac catheterization laboratory, we transitioned to performing the procedure at the patient's bedside in the neonatal intensive care unit using echocardiographic guidance. The bedside approach has the potential to expand this therapy to patients who currently undergo expectant PDA management because of lack of availability of this therapy, and allow for earlier referral, which will reduce time of exposure to this pathologic shunt.

Contemporary fluid management, humidity, and patent ductus arteriosus management strategy for premature infants among 336 hospitals in Asia

Objectives

The management of patent ductus arteriosus (PDA) is a critical concern in premature infants, and different hospitals may have varying treatment policies, fluid management strategies, and incubator humidity. The Asian Neonatal Network Collaboration (AsianNeo) collected data on prematurity care details from hospitals across Asian countries. The aim of this study was to provide a survey of the current practices in the management of PDA in premature infants in Asian countries.

Methods

AsianNeo performed a cross-sectional international questionnaire survey in 2022 to assess the human and physical resources of hospitals and clinical management of very preterm infants. The survey covered various aspects of hospitals resources and clinical management, and data were collected from 337 hospitals across Asia. The data collected were used to compare hospitals resources and clinical management of preterm infants between areas and economic status.

Results

The policy of PDA management for preterm infants varied across Asian countries in AsianNeo. Hospitals in Northeast Asia were more likely to perform PDA ligation (p < 0.001) than hospitals in Southeast Asia. Hospitals in Northeast Asia had stricter fluid restrictions in the first 24 h after birth for infants born at <29 weeks gestation (p < 0.001) and on day 14 after birth for infants born at <29 weeks gestation (p < 0.001) compared to hospitals in Southeast Asia. Hospitals in Northeast Asia also had a more humidified environment for infants born between 24 weeks gestation and 25 weeks gestation in the first 72 h after birth (p < 0.001). A logistic regression model predicted that hospitals were more likely to perform PDA ligation for PDA when the hospitals had a stricter fluid planning on day 14 after birth [Odds ratio (OR) of 1.70, p = 0.048], more incubator humidity settings (<80% vs. 80%-89%, OR of 3.35, p = 0.012 and <80% vs. 90%-100%, OR of 5.31, p < 0.001).

Conclusions

In advanced economies and Northeast Asia, neonatologists tend to adopt a more conservative approach towards fluid management, maintain higher incubator humidity settings and inclined to perform surgical ligation for PDA.

Expectant Management or Early Ibuprofen for Patent Ductus Arteriosus

BACKGROUND

Cyclooxygenase inhibitors are commonly used in infants with patent ductus arteriosus (PDA), but the benefit of these drugs is uncertain.

METHODS

In this multicenter, noninferiority trial, we randomly assigned infants with echocardiographically confirmed PDA (diameter, >1.5 mm, with left-to-right shunting) who were extremely preterm (<28 weeks' gestational age) to receive either expectant management or early ibuprofen treatment. The composite primary outcome included necrotizing enterocolitis (Bell's stage IIa or higher), moderate to severe bronchopulmonary dysplasia, or death at 36 weeks' postmenstrual age. The noninferiority of expectant management as compared with early ibuprofen treatment was defined as an absolute risk difference with an upper boundary of the one-sided 95% confidence interval of less than 10 percentage points.

RESULTS

A total of 273 infants underwent randomization. The median gestational age was 26 weeks, and the median birth weight was 845 g. A primary-outcome event occurred in 63 of 136 infants (46.3%) in the expectant-management group and in 87 of 137 (63.5%) in the early-ibuprofen group (absolute risk difference, -17.2 percentage points; upper boundary of the one-sided 95% confidence interval [CI], -7.4; P<0.001 for noninferiority). Necrotizing enterocolitis occurred in 24 of 136 infants (17.6%) in the expectant-management group and in 21 of 137 (15.3%) in the early-ibuprofen group (absolute risk difference, 2.3 percentage points; two-sided 95% CI, -6.5 to 11.1); bronchopulmonary dysplasia occurred in 39 of 117 infants (33.3%) and in 57 of 112 (50.9%), respectively (absolute risk difference, -17.6 percentage points; two-sided 95% CI, -30.2 to -5.0). Death occurred in 19 of 136 infants (14.0%) and in 25 of 137 (18.2%), respectively (absolute risk difference, -4.3 percentage points; two-sided 95% CI, -13.0 to 4.4). Rates of other adverse outcomes were similar in the two groups.

CONCLUSIONS

Expectant management for PDA in extremely premature infants was noninferior to early ibuprofen treatment with respect to necrotizing enterocolitis, bronchopulmonary dysplasia, or death at 36 weeks' postmenstrual age. (Funded by the Netherlands Organization for Health Research and Development and the Belgian Health Care Knowledge Center; BeNeDuctus ClinicalTrials.gov number, NCT02884219; EudraCT number, 2017-001376-28.).

Combination pharmacotherapy for patent ductus arteriosus: Rationale and evidence

While cyclooxygenase inhibitors have been the most common medications used to facilitate earlier closure of patent ductus arteriosus in preterm infants, adverse effects and low efficacy in extremely low gestational age neonates (ELGANs) have highlighted a need for alternative options. Combination therapy with acetaminophen and ibuprofen is a novel strategy for PDA treatment in ELGANs, as it may facilitate higher ductal closure rates via additive action on two separate pathways inhibiting prostaglandin production. Initial small observational studies and pilot randomized clinical trials indicate potentially higher efficacy of the combination regime to induce ductal closure in comparison to treatment with ibuprofen alone. In this review, we examine the potential clinical impact of treatment failure in ELGANs with significant PDA, highlight the biological rationale in support of studying combination therapy, and review the randomized and non-randomized studies to date. With the rising number of ELGANs receiving neonatal intensive care, who are vulnerable to PDA-related morbidities, there is an urgent need for adequately powered clinical trials to systematically investigate the efficacy and safety of combination therapy for PDA treatment.

Growth and differentiation factor 15 (GDF15) levels predict adverse respiratory outcomes in premature neonates

Growth and differentiation factor 15 (GDF15) is a stress-responsive cytokine, and its expression increases during inflammation, hyperoxia, and senescence. Significantly, GDF15 is secreted by the placenta, and maternal levels increase throughout pregnancy. Serum GDF15 level is a promising biomarker for many lung diseases like pulmonary hypertension and pulmonary fibrosis. However, circulating GDF15 levels in preterm infants and their role as a predictor of respiratory outcomes have not been studied. We hypothesized that GDF15 levels would increase with gestational age at birth, and that postnatal GDF15 will be correlated with adverse respiratory outcomes in preterm infants. Scavenged blood samples were retrieved from 57 preterm infants at five time points, from birth until 36-weeks postmenstrual age (PMA). GDF15 levels were measured using ELISA in 114 samples. We performed two-sample t-test, correlation and linear regression, logistic regression, and mixed-effects linear models for statistical analysis, and significance was identified when p < 0.05. Contrary to our hypothesis, for every 1-week increase in gestational age at birth, the predicted GDF15 level decreased by 475.0 pg/ml (p < 0.001). Greater PMA was significantly associated with lower serum GDF15 levels (p < 0.001). Interestingly, higher GDF15 levels were associated with a longer need for mechanical ventilation (p = 0.034), prolonged respiratory support need (p < 0.001), and length of hospital stay (p = 0.006). In conclusion, in preterm infants, GDF15 levels show an inverse correlation with gestational age at birth, with higher levels in more preterm babies, and levels trend down postnatally. Furthermore, longitudinal GDF15 levels through 36 weeks PMA predict adverse respiratory outcomes in preterm infants.

Predictors of successful patent ductus arteriosus closure with acetaminophen in preterm infants

OBJECTIVE

Evaluate predictors of successful PDA closure following acetaminophen treatment.

STUDY DESIGN

Retrospective cohort study of ≤30 weeks GA infants born from 1 January 2013-30 September 2019, and treated with single course acetaminophen by symptomatic PDA treatment strategy. Multiple maternal and neonatal variables were identified as potential predictors. Univariate analysis and multivariable regression models were applied to evaluate the strongest predictors.

RESULTS

Sixty-six patients were included, 28 (42.4%) had successful PDA closure following acetaminophen. Success was associated with GA > 26 weeks (65% vs. 33%, AUC = 0.64), birthweight >750 g (53% vs. 32%, AUC = 0.61), PDA size ≤0.2 cm (63% vs. 32%, AUC = 0.64), and no prior indomethacin use (56% vs. 33%, AUC = 0.61). Multivariable model identified GA > 26 weeks (RR = 1.92, CI 1.20-3.09) and PDA size ≤0.2 cm (RR: 1.82, CI 1.11-2.98) as the strongest predictors.

CONCLUSION

Acetaminophen may be more successful in targeted PDA closure in >26 weeks GA infants with PDA size ≤0.2 cm.

Conservative Treatment Without Any Intervention Compared With Other Therapeutic Strategies for Symptomatic Patent Ductus Arteriosus in Extremely Preterm Infants: A Nationwide Cohort Study in Korea

Objective: Although symptomatic treatment is the most preferred treatment strategy for proven symptomatic patent ductus arteriosus (PDA), a considerable number of infants only received conservative treatment without any pharmacological or surgical interventions in the lower gestational age and lower birth weight group in Korea. We compared in-hospital outcomes of infants treated conservatively without any intervention and those of infants managed by other therapeutic strategies in extremely preterm infants with symptomatic PDA. Methods: A prospectively collected cohort study for 2,303 infants with gestational ages <28 weeks from the Korean Neonatal Network database. These infants were classified into four groups according to the presence of PDA-related symptoms and therapeutic treatment strategy: prophylactic treatment group, pre-symptomatic treatment (PST) group, symptomatic treatment (ST) group, and conservative treatment (CT) without any intervention group. Results: In multivariable logistic regression analysis, the risk of death was significantly decreased in the PST group (adjusted odds ratio [aOR] = 0.507; 95% confidence interval [CI] 0.311-0.826) and ST group (aOR = 0.349; 95% CI: 0.230-0.529) compared with the CT group. However, the risk of composite outcome of severe bronchopulmonary dysplasia or death had not increased in the PST group and ST group. Neonatal death due to pulmonary hemorrhage or neurological disease was significantly higher in the CT group than in the PST group or ST group. Conclusion: In extremely preterm infants, who are at highest risk of PDA-related morbidities and mortality, even less interventional approach for PDA can be allowed; the rescued pharmacological or surgical interventions are necessary if they met the criteria for hemodynamically significant PDA.

Hemodynamic and clinical consequences of early versus delayed closure of patent ductus arteriosus in extremely low birth weight infants

OBJECTIVES

To describe changes in hemodynamics, respiratory support, and growth associated with transcatheter PDA closure (TCPC) in ELBW infants, stratified by postnatal age at treatment.

STUDY DESIGN

This is an observational study of ELBW infants who underwent TCPC at ≤4 weeks (Group-1; n = 34), 4-8 weeks (Group-2; n = 33), and >8 weeks of age (Group-3; n = 33). Hemodynamic assessment was performed during TCPC. Multivariate Cox-proportionate-hazard modeling was used to identify factors associated with respiratory severity score (RSS) > 2 for >30 days following TCPC.

RESULTS

In comparison with Group-1, Group-3 infants had higher pulmonary vascular resistance (PVRi = 3.3 vs. 1.6 WU*m²; P = 0.01), less weight gain between 4 and 8 weeks of age (16 vs. 25 g/day) and took longer to achieve RSS < 2 (median 81 vs. 20 days; P = 0.001). RSS > 2 for >30 days was associated with TCPC > 8 weeks (OR = 3.2, 95% CI: 1.75-5.8; p = 0.03) and PVRi ≥ 3 (OR = 4.5, 95% CI: 2.7-8.9; p < 0.01).

CONCLUSION

ELBW infants may benefit from PDA closure within the first 4 weeks of life in order to prevent early onset pulmonary vascular disease, promote faster growth, and for quicker weaning of ventilator and oxygen support.

Amplatzer Piccolo Occluder clinical trial for percutaneous closure of the patent ductus arteriosus in patients ≥700 grams

Objectives

Characterize the safety and effectiveness of the Amplatzer Piccolo Occluder for patent ductus arteriosus (PDA) closure.

Background

The presence of a hemodynamically significant PDA has been associated with an increased risk of morbidity and mortality in children born premature.

Methods

This was a single arm, prospective, multicenter, non‐randomized study to evaluate the Amplatzer Piccolo Occluder to treat PDA in patients ≥700 g. From June 2017 to February 2019, 200 patients were enrolled at nine centers, with 100 patients weighing ≤2 kg. Primary effectiveness endpoint was the rate of PDA closure at 6‐month follow‐up. Primary safety endpoint was the rate of major complications through 6 months. Secondary endpoint was rate of significant pulmonary or aortic obstruction through 6 months' follow‐up.

Results

The implant success rate was 95.5% (191/200) overall and 99% in patients ≤2 kg (99/100). The primary effectiveness endpoint was achieved in 99.4% of implanted patients. Four patients experienced a primary safety endpoint event (2 transfusions, 1 hemolysis, and 1 aortic obstruction). There were no branch pulmonary artery obstructions. Five patients, all ≤2 kg, were noted to have worsening of tricuspid regurgitation (TR) after the procedure. None of the TR incidences manifested clinically. The Amplatzer Piccolo Occluder received FDA approval in January 2019 and became the first device approved for PDA closure in patients ≥700 g.

Conclusions

This study supports the safety and effectiveness of the Amplatzer Piccolo Occluder, particularly in patients between 700 g and 2 kg where there is currently a significant unmet need in the United States. ClinicalTrials.gov identifier: NCT03055858.

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.

From Galen to Gross and beyond: a brief history of the enigmatic patent ductus arteriosus

Anatomists since antiquity and pathologists since at least the 17th century had identified the ductus arteriosus (DA) in cadavers and postmortem examinations, respectively. However, healthcare providers for more than a century have struggled to understand the significance of a patent ductus arteriosus (PDA) in patients, debated whether to treat it or not and if so, when and how. Accepted answers depended upon the authoritative position of the person(s) offering recommendations, the cumulative contemporary medical knowledge, and the changing patient population characteristics. The treatment choices were most often based on one's understanding of the balance between the risks and benefits of the chosen treatment. In the current era, with the increasing popularity of transcatheter occlusion of the PDA with relative ease even in extremely premature infants whose survival rates have improved dramatically, a basic question has reemerged-what are the benefits to treating the PDA in any preterm infant. In this brief review, I am providing a chronicle of the evolution of knowledge about the DA, the varying nature of the challenges a patent ductus posed for the caregivers, and the roots of the continued debate concerning the management of the enigmatic PDA.

Regional tissue oxygenation monitoring in the neonatal intensive care unit: evidence for clinical strategies and future directions

Near-infrared spectroscopy (NIRS)-based monitoring of regional tissue oxygenation (rSO₂) is becoming more commonplace in the neonatal intensive care unit (NICU). While increasing evidence supports rSO₂ monitoring, actual standards for applying this noninvasive bedside technique continue to evolve. This review highlights the current strengths and pitfalls surrounding practical NIRS-based monitoring in the neonatal population. The physiologic background of rSO₂ monitoring is discussed, with attention to understanding oxygen delivery/consumption mismatch and its effects on tissue oxygen extraction. The bedside utility of both cerebral and peripheral rSO₂ monitoring in the NICU is then explored from two perspectives: (1) disease/event-specific "responsive" monitoring and (2) "routine," continuous monitoring. Recent evidence incorporating both monitoring approaches is summarized with emphasis on practical applicability in the NICU. Finally, a future paradigm for a broad-based NIRS monitoring strategy is presented, with attention towards improving personalization of neonatal care and ultimately enhancing long-term outcomes.