Prematurity and Pulmonary Vein Stenosis: The Role of Parenchymal Lung Disease and Pulmonary Vascular Disease

The burden of innovation in the pediatric heart center

PURPOSE OF REVIEW

The purpose of this review is to elucidate the growing complexity involved in providing pediatric cardiac care in the contemporary era of innovation. Aiming to highlight the phenomenon of chronic critical illness in a pediatric heart center, this review outlines the burdens placed on those caring for these uniquely challenging patients and poses considerations for alleviating those burdens.

RECENT FINDINGS

As care advancements drive improved survival for children with heart disease, heart centers face a growing population of chronically critically ill patients with high resource utilization and uncertain trajectories. Preterm infants, single ventricles, and complex heart failure patients require significant interventions and expertise. Their lengthy courses challenge care delivery systems and resources, in addition to placing significant emotional and cognitive burdens on the multidisciplinary teams.

SUMMARY

The growing population of chronically critically ill cardiac patients are some of the most challenging both at the system level and on the team members. While undertaking innovative therapies, we must recognize that survival as an outcome cannot be separated from associated costs of achieving that outcome; the resultant burdens of innovation cannot be ignored. Heart centers must take a proactive stance in optimizing care for children with prolonged illness while also addressing the needs of those who care for them.

Ante-mortem diagnosis of unilateral pulmonary vein stenosis in a cat: a case report

BACKGROUND

Pulmonary hypertension (PH) detection in cats may be challenging. Pulmonary venous stenosis (PVS) is rare in cats and can lead to PH. The only reported PVS case received a post-mortem diagnosis. Imaging during the cat's lifetime established the diagnosis in this case.

CASE PRESENTATION

A 2 year-old Norwegian Forest cat was diagnosed with pulmonary oedema and PH secondary to cor triatriatum sinister (CTS) and showed improved breathing following two subcutaneous furosemide treatments, 1 and 2 mg/kg, during an overnight stay at the referral veterinary hospital. Sildenafil alone (0.69 mg/kg, PO, BID) was prescribed post-discharge to address PH without diuretics. Post-discharge from the referral veterinary hospital, collapse and pre-syncope were suspected to be due to PH. Consequently, sildenafil was titrated weekly, starting at 1.09 mg/kg BID and increasing to 1.63 mg/kg BID. Pre-syncope and collapse resolved, and pulmonary opacities reduced considerably, although concerns remained that increased pulmonary blood flow to suspected CTS from sildenafil might worsen cardiogenic pulmonary oedema. The patient was also treated with rivaroxaban (2.5 mg/head, SID), considering the increased risk of thrombus formation due to blood flow stasis and endothelial damage. Thirty-eight days later, the cat presented for the first time to our hosipital (Azabu University Veterinary Teaching Hospital) for examination. On echocardiography, a continuous mosaic blood flow (maximum and minimum velocity, 3.14 m/s; estimated pressure gradient, 39.4 mmHg) was observed in two enlarged pulmonary veins. Pulmonary artery enlargement (main pulmonary artery to thoracic aorta ratio: 1.90), pulmonary vein stenosis (PVS), and diffuse bilateral ground-glass lung opacities were observed using computed tomography. PH with unilateral PVS involving two out of the three right pulmonary veins, specifically the right cranial and right middle pulmonary veins, along with pulmonary parenchymal disease, was diagnosed. The cat was further treated with furosemide (1 mg/kg, BID, PO) with no clinical signs but succumbed to acute dyspnoea 51 days after the first visit.

CONCLUSIONS

Unilateral PVS should be considered in young cats with a localised alveolar pattern and no left atrial enlargement, because the prognosis may be poor. Severe PH with PVS may coexist with lung disease. If sildenafil is used, it should be started at a low dose and monitored closely.

Validation of the NICHD Bronchopulmonary Dysplasia Outcome Estimator 2022 in a Quaternary Canadian NICU-A Single-Center Observational Study

Background/Objectives: The numerical risk of bronchopulmonary dysplasia (BPD) and/or death could be estimated using the National Institute of Child Health and Human Development (NICHD) BPD outcome estimator 2022 in extremely low gestational age (ELGA) infants during the first 4 weeks of life to facilitate prognostication, and center-specific targeted improvement interventions. However, the 2022 NICHD BPD outcome estimator's performance in the Canadian setting has not been validated. Our objective is to validate the NICHD BPD outcome estimator 2022 in predicting death and or moderate to severe BPD at 36 weeks in infants less than 29 weeks admitted to NICU. Methods: A retrospective observational study (March 2022-August 2023) was conducted on both inborn and outborn preterm infants excluding neonates with major congenital anomalies. Infants were classified into six groups based on the predicted risk of death or Grade 2 or 3 BPD (<10%, 10-20%, 20-30%, 30-40%, 50-59%, ≥60%) followed by noting observed outcomes from the unit's database. A receiver operating characteristics (ROC) curve was used to assess the accuracy of the NICHD BPD outcome estimator 2022, with an area under curve (AUC) > 0.7 defined a priori as an acceptable predictive accuracy for local use. Results: Among 99 infants included, 13 (13.1%) died, and 40 (40.4%) developed BPD. Median gestational age was 26 weeks, and median birth weight was 914 g. Twenty-three infants (23.2%) received postnatal steroids. The AUC values for death or moderate to severe BPD on days 1, 3, 7, 14, and 28 were 0.803, 0.806, 0.837, 0.832, and 0.843, respectively. The AUC values for moderate to severe BPD alone on those days were 0.766, 0.746, 0.785, 0.807, and 0.818 respectively. Conclusions: The 2022 BPD estimator adequately predicted the death and/or moderate to severe BPD on days 1, 3, 7, 14, and 28 of life. This tool could serve as a valid adjunct to facilitate discussion between clinicians and families on initiating time-sensitive targeted interventions to prevent or alter the course of BPD.

Serial echocardiography in preterm infants with bronchopulmonary dysplasia: diagnosing and managing recurrent pulmonary vein stenosis

Objectives

To highlight the importance of serial echocardiography in preterm infants with bronchopulmonary dysplasia (BPD) to diagnose recurrent pulmonary vein stenosis (PVS) and understand its contribution to respiratory deteriorations.

Case presentation

A preterm female infant born at 23+5 weeks gestation had numerous complications related to extreme prematurity, including BPD. She was diagnosed with PVS on echocardiogram after experiencing recurrent respiratory deteriorations and pulmonary hypertensive crises. Initial management involved transcutaneous balloon dilatation. A serial echocardiographic programme was implemented, with weekly monitoring of PVS. She suffered multiple respiratory deteriorations secondary to recurrence of PVS, necessitating repeat cardiac catheterisations and transcatheter stenting. Systemic macrolide therapy with sirolimus was used as adjunctive therapy.

Conclusions

Extremely prematurely born infants who develop BPD are at higher risk of recurrent PVS. We demonstrate that serial echocardiographic monitoring facilitates early diagnosis and prompt intervention of PVS. Any respiratory deterioration in such infants should be assessed by an echocardiogram.

Neonatal Risk Factors for Pulmonary Vein Stenosis in Infants Born Preterm with Severe Bronchopulmonary Dysplasia

OBJECTIVE

To evaluate associations between neonatal risk factors and pulmonary vein stenosis (PVS) among infants born preterm with severe bronchopulmonary dysplasia (sBPD).

STUDY DESIGN

We performed a case-control study of infants born from 2010 to 2022 at <32 weeks' gestation with sBPD among 46 neonatal intensive care units in the Children's Hospitals Neonatal Consortium. Cases with PVS were matched to controls using epoch of diagnosis (2010-2016; 2017-2022) and hospital. Multivariable logistic regression analyses were utilized to evaluate PVS association with neonatal risk factors.

RESULTS

From 10 171 preterm infants with sBPD, we identified 109 cases with PVS and matched those to 327 controls. The prevalence of PVS (1.07%) rose between epochs (0.8% in 2010-2016 to 1.2% in 2017-2022). Relative to controls, infants with PVS were more likely to be <500 g at birth, to be small for gestational age <10th%ile, or have surgical necrotizing enterocolitis, atrial septal defects, or pulmonary hypertension. In multivariable models, these associations persisted, and small for gestational age, surgical necrotizing enterocolitis, atrial septal defects, and pulmonary hypertension were each independently associated with PVS. Among infants on respiratory support at 36 weeks' postmenstrual age, infants with PVS had 4.3-fold higher odds of receiving mechanical ventilation at 36 weeks' postmenstrual age. Infants with PVS also had 3.6-fold higher odds of in-hospital mortality relative to controls.

CONCLUSIONS

In a large cohort of preterm infants with sBPD, multiple independent, neonatal risk factors are associated with PVS. These results lay important groundwork for the development of targeted screening to guide the diagnosis and management of PVS in preterm infants with sBPD.

An interdisciplinary consensus approach to pulmonary hypertension in developmental lung disease

It is increasingly recognised that diverse genetic respiratory disorders present as severe pulmonary hypertension (PH) in the neonate and young infant, but many controversies and uncertainties persist regarding optimal strategies for diagnosis and management to maximise long-term outcomes. To better define the nature of PH in the setting of developmental lung disease (DEVLD), in addition to the common diagnoses of bronchopulmonary dysplasia and congenital diaphragmatic hernia, we established a multidisciplinary group of expert clinicians from stakeholder paediatric specialties to highlight current challenges and recommendations for clinical approaches, as well as counselling and support of families. In this review, we characterise clinical features of infants with DEVLD/DEVLD-PH and identify decision-making challenges including genetic evaluations, the role of lung biopsies, the use of imaging modalities and treatment approaches. The importance of working with team members from multiple disciplines, enhancing communication and providing sufficient counselling services for families is emphasised to create an interdisciplinary consensus.

Interventions for Pulmonary Vein Stenosis

Pulmonary vein stenosis (PVS) is a rare and unique disease of infants and young children. PVS is attended by high morbidity and mortality, and for many decades, effective therapy eluded the practitioner. However, in the most recent era, interventional techniques when employed in combination with systemic (primary) therapy have had a remarkable impact on outcomes in these at-risk children. Despite apparent complete relief of PVS in a discrete region of a pulmonary vein, stenosis reliably recurs and progresses. In this review, we discuss the current state-of-the-art interventional techniques, through the lens of our collective experiences and practices.

Navigating Diagnostic and Treatment Challenges of Pulmonary Hypertension in Infants with Bronchopulmonary Dysplasia

Advances in perinatal intensive care have significantly enhanced the survival rates of extremely low gestation-al-age neonates but with continued high rates of bronchopulmonary dysplasia (BPD). Nevertheless, as the survival of these infants improves, there is a growing awareness of associated abnormalities in pulmonary vascular development and hemodynamics within the pulmonary circulation. Premature infants, now born as early as 22 weeks, face heightened risks of adverse development in both pulmonary arterial and venous systems. This risk is compounded by parenchymal and airway abnormalities, as well as factors such as inflammation, fibrosis, and adverse growth trajectory. The presence of pulmonary hypertension in bronchopulmonary dysplasia (BPD-PH) has been linked to an increased mortality and substantial morbidities, including a greater susceptibility to later neurodevelopmental challenges. BPD-PH is now recognized to be a spectrum of disease, with a multifactorial pathophysiology. This review discusses the challenges associated with the identification and management of BPD-PH, both of which are important in minimizing further disease progression and improving cardiopulmonary morbidity in the BPD infant.

Pathogenesis and Physiologic Mechanisms of Neonatal Pulmonary Hypertension: Preclinical Studies

Neonatal pulmonary hypertension (PH) is a devastating disorder of the pulmonary vasculature characterized by elevated pulmonary vascular resistance and mean pulmonary arterial pressure. Occurring predominantly because of maldevelopment or maladaptation of the pulmonary vasculature, PH in neonates is associated with suboptimal short-term and long-term outcomes because its pathobiology is unclear in most circumstances, and it responds poorly to conventional pulmonary vasodilators. Understanding the pathogenesis and pathophysiology of neonatal PH can lead to novel strategies and precise therapies. The review is designed to achieve this goal by summarizing pulmonary vascular development and the pathogenesis and pathophysiology of PH associated with maladaptation, bronchopulmonary dysplasia, and congenital diaphragmatic hernia based on evidence predominantly from preclinical studies. We also discuss the pros and cons of and provide future directions for preclinical studies in neonatal PH.