Pulmonary vascular disease in bronchopulmonary dysplasia: pulmonary hypertension and beyond

Purpose of review Pulmonary hypertension contributes significantly to morbidity and mortality of chronic lung disease of infancy, or bronchopulmonary dysplasia (BPD). Advances in pulmonary vascular biology over the past few decades have led to new insights into the pathogenesis of BPD; however, many unique issues persist regarding our understanding of pulmonary vascular development and disease in preterm infants at risk for chronic lung disease. Recent findings Recent studies have highlighted the important contribution of the developing pulmonary circulation to lung growth in the setting of preterm birth. These studies suggest that there is a spectrum of pulmonary vascular disease (PVD) in BPD rather than a simple question of whether or not pulmonary hypertension is present. Epidemiological studies underscore gaps in our understanding of PVD in the context of BPD, including universally accepted definitions, approaches to diagnosis and treatment, and patient outcomes. Unfortunately, therapeutic strategies for pulmonary hypertension in BPD are based on small observational studies with poorly defined endpoints and rely on results from older children and adult studies. Yet, unique characteristics of this population create other potential risks for the adoption of these strategies. Summary Despite many recent advances, PVD remains an important contributor to poor outcomes in preterm infants with BPD. Substantial challenges persist, especially with regard to understanding mechanisms and the clinical approach to PVD. Future studies are needed to develop evidence-based definitions and clinical endpoints through which the pathophysiology can be investigated and potential therapeutic interventions evaluated.