Pulmonary Hypertension in Preterm Infants with Bronchopulmonary Dysplasia

Abstract

Bronchopulmonary dysplasia (BPD), the chronic lung disease of prematurity, is a significant contributor to perinatal morbidity and mortality. Premature birth disrupts pulmonary vascular growth and initiates a cascade of events that result in impaired gas exchange, abnormal vasoreactivity, and pulmonary vascular remodeling that may ultimately lead to pulmonary hypertension (PH). Even infants who appear to have mild BPD suffer from varying degrees of pulmonary vascular disease (PVD). Although recent studies have enhanced our understanding of the pathobiology of PVD and PH in BPD, much remains unknown with respect to how PH should be properly defined, as well as the most accurate methods for the diagnosis and treatment of PH in infants with BPD. This article will provide neonatologists and primary care providers, as well as pediatric cardiologists and pulmonologists, with a review of the pathophysiology of PH in preterm infants with BPD and a summary of current clinical recommendations for managing PH in this population.

Figures

FIG. 1.

Pathophysiology of pulmonary hypertension (PH) in bronchopulmonary dysplasia (BPD). Prenatal and postnatal factors impair angiogenic signaling, resulting in disrupted vascular growth, abnormal vascular function, and ultimately, PH.

FIG. 2.

(A) In the normal perinatal lung, intrapulmonary arteriovenous anastomotic vessels (IAAV) are closed or nonexistent. Blood from a small pulmonary artery (PA) becomes oxygenated at the alveolar–capillary interface before entering a pulmonary vein (PV). (B) In infants with BPD, deoxygenated blood passes through IAAV before becoming oxygenated in the microcapillary bed causing hypoxemia in these patients.