Vasodilator therapy for pulmonary hypertension in children: a national study of patient characteristics and current treatment strategies

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.

Risk factors for isolated atrial septal defect secundum morbidity

Atrial septal defect secundum is a common type of congenital heart defect and even more common among children born premature. The aim of this study was to assess premature birth as a potential associated risk factors for cardiac morbidity in children with isolated ASD II. In this retrospective national registry-based case-control study all children born in Sweden between 2010 and 2015 with an isolated ASD II diagnosis were included. Association between premature birth and cardiac morbidity in children with isolated ASD II was assessed by different outcomes-models using conditional logistic regression and adjustments were made for confounding factors. Overall, 11% of children with an isolated ASD II received treatment for heart failure. Down syndrome was the only independent risk factors for associated with cardiac morbidity in children with ASD II (OR = 2.25 (95%CI 1.25-4.07). Preterm birth in children was not associated with an increased risk of ASD II cardiac morbidity.

Advances in targeted therapy for pulmonary arterial hypertension in children

Pulmonary arterial hypertension (PAH) is a rare and devastating disease of the pulmonary vasculature with a high morbidity and mortality rate in infants and children. Currently, treatment approaches are mostly based on adult guidelines and pediatrician clinical experience, focusing on specific pulmonary antihypertensive therapy and conventional supportive care. The advent of targeted drugs has led to significant advances in the treatment of PAH in children, including endothelin receptor antagonists, phosphodiesterase type 5 inhibitors, and prostacyclins, which have been studied and proven to improve hemodynamics and functional class in children PAH. A new targeted drug, riociguat, is assessing its safety and efficacy in clinical trials. However, more randomized controlled studies are needed to evaluate the combination of drugs, treatment strategies, and clinical endpoints of targeted therapy in children PAH. In this review, we summarize the research advances of PAH-targeted therapy in children over the last decade in order to provide a theoretical basis for future studies.

CONCLUSION

Pulmonary arterial hypertension (PAH) is a rare and devastating pulmonary vascular disease that is associated with a variety of diseases of any age in childhood onset.

WHAT IS KNOWN

• Therapeutic strategies for targeted drugs for PAH in children are based almost exclusively on data from adult studies and clinical experience of pediatric specialists. • Due to the complex etiology of PAH in children and the relative lack of clinical trial data, the selection of appropriate targeted drug therapy remains difficult.

WHAT IS NEW

• We redefine the definition of pulmonary arterial hypertension in children and summarize the progress of targeted therapy of pulmonary arterial hypertension in children in the past ten years. • The dosage and adverse reactions were summarized, and the mechanism of action was drawn according to the available targeted drugs. It can provide theoretical support for the development of guidelines and treatment strategies for the diagnosis and treatment of pulmonary arterial hypertension in children.

The vascular phenotype of BPD: new basic science insights-new precision medicine approaches

Bronchopulmonary dysplasia (BPD) is the most common complication of preterm birth. Up to 1/3 of children with BPD develop pulmonary hypertension (PH). PH increases mortality, the risk of adverse neurodevelopmental outcome and lacks effective treatment. Current vasodilator therapies address symptoms, but not the underlying arrested vascular development. Recent insights into placental biology and novel technological advances enabling the study of normal and impaired lung development at the single cell level support the concept of a vascular phenotype of BPD. Dysregulation of growth factor pathways results in depletion and dysfunction of putative distal pulmonary endothelial progenitor cells including Cap1, Cap2, and endothelial colony-forming cells (ECFCs), a subset of vascular progenitor cells with self-renewal and de novo angiogenic capacity. Preclinical data demonstrate effectiveness of ECFCs and ECFC-derived particles including extracellular vesicles (EVs) in promoting lung vascular growth and reversing PH, but the mechanism is unknown. The lack of engraftment suggests a paracrine mode of action mediated by EVs that contain miRNA. Aberrant miRNA signaling contributes to arrested pulmonary vascular development, hence using EV- and miRNA-based therapies is a promising strategy to prevent the development of BPD-PH. More needs to be learned about disrupted pathways, timing of intervention, and mode of delivery. IMPACT: Single-cell RNA sequencing studies provide new in-depth view of developmental endothelial depletion underlying BPD-PH. Aberrant miRNA expression is a major cause of arrested pulmonary development. EV- and miRNA-based therapies are very promising therapeutic strategies to improve prognosis in BPD-PH.

Molecular genetics of pulmonary hypertension in children

Until recently, the molecular aetiology of paediatric pulmonary hypertension (PH) was relatively poorly understood. While the TGF-β/BMP pathway was recognised as central to disease progression, genetic analyses in children were largely confined to targeted screening of risk genes in small cohorts, with clinical management extrapolated from adult data. In recent years, next-generation sequencing has highlighted notable differences in the genetic architecture underlying childhood-onset cases, with a higher genetic burden in children partly explained by comorbidities such as congenital heart disease. Here, we review recent genetic advances in paediatric PH and highlight important risk factors such as dysregulation of the transcription factors SOX17 and TBX4. Given the poorer prognosis in paediatric cases, molecular diagnosis offers a vital tool to enhance clinical care of children with PH.