Primary pulmonary vein stenosis in a premature infant without bronchopulmonary dysplasia: A case report

Pulmonary Vascular Phenotypes of Prematurity: The Path to Precision Medicine

Pulmonary hypertension (PH) is associated with significant morbidities and high mortality in preterm infants, yet mechanisms contributing to the pathogenesis of PH, the impact of early pulmonary vascular disease (PVD) on the risk for BPD, the role for PH-targeted drug therapies, and long-term pulmonary vascular sequelae remain poorly understood. PVD is not a homogeneous disease, rather, PVD in the setting of prematurity includes various phenotypes as based on underlying pathophysiology, the severity of associated PH, the timing of disease onset, its contribution to hemodynamic and respiratory status, late outcomes, and other features. As with term newborns, severe hypoxemia with acute respiratory failure (HRF) in preterm infants can be due to marked elevation of pulmonary artery pressure with extrapulmonary shunt, traditionally referred to as persistent pulmonary hypertension of the newborn (PPHN). Transient and less severe levels of PH can also be observed during the early transition after birth without evidence of severe HRF, representing physiologic PH or delayed pulmonary vascular transition in preterm infants. Importantly, echocardiographic evidence of early PH has been strongly associated with the subsequent development of bronchopulmonary dysplasia (BPD), late PH, and chronic respiratory disease during infancy and early childhood. Late PH beyond the first postnatal months in preterm in neonates with established BPD is further associated with poor outcomes, especially as related to BPD severity. In addition, echocardiographic signs of PVD can further persist throughout childhood and may lead to chronic PH of variable severity and cardiac maldevelopment in prematurely born young adults. This review discusses the importance of characterizing diverse pulmonary vascular phenotypes in preterm infants to better guide clinical care and research, and to enhance the development of more precise therapeutic strategies to optimize early and late outcomes of preterm infants.

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

Pulmonary vein stenosis (PVS) has emerged as a critical problem in premature infants with persistent respiratory diseases, particularly bronchopulmonary dysplasia (BPD). As a parenchymal lung disease, BPD also influences vascular development with associated pulmonary hypertension recognized as an important comorbidity of both BPD and PVS. PVS is commonly detected later in infancy, suggesting additional postnatal factors that contribute to disease development, progression, and severity. The same processes that result in BPD, some of which are inflammatory-mediated, may also contribute to the postnatal development of PVS. Although both PVS and BPD are recognized as diseases of inflammation, the link between them is less well-described. In this review, we explore the relationship between parenchymal lung diseases, BPD, and PVS, with a specific focus on the epidemiology, clinical presentation, risk factors, and plausible biological mechanisms in premature infants. We offer an algorithm for early detection and prevention and provide suggestions for research priorities.

Pulmonary vein stenosis of ex-premature infants with pulmonary hypertension and bronchopulmonary dysplasia, epidemiology, and survival from a multicenter cohort

BACKGROUND

Pulmonary vein stenosis is emerging as an important clinical problem in ex-premature infants.

METHODS

We sought to describe the epidemiology of pulmonary vein stenosis affecting ex-premature infants by a multicenter retrospective cohort study of patients from seven children's hospitals diagnosed between 2000-2014.

RESULTS

We identified 39 ex-premature patients (26 males, median gestational age 28 weeks range 22-36 weeks, birth weight 1.1 kg range 433-2645-g) with pulmonary vein stenosis. Median age at diagnosis was 6.5 months (1 month-6 years). Presentation with pulmonary hypertension occurred in 26/39 (67%) and 29/39 (74%) had bronchopulmonary dysplasia, 15 (39%) were born of twin pregnancies with unaffected twin siblings. A median of 5 (range 1-25) echocardiograms was performed prior to diagnosis. The diagnosis was made using echocardiography in 22/39 (56%), by multi-detector contrast computed tomography scan (CT) in 8/39 (21%), cardiac catheterization in 6/39 (15%) patients, magnetic resonance imaging in 3/39 (8%). Freedom from death or re-stenosis was 73% at 1-year, 55% at 2, 5, and 10 years. Factors associated with shorter survival or re-stenosis were stenosis of  ≥3 pulmonary veins (P < 0.01), bilateral pulmonary vein stenosis (P < 0.01) small for gestational age (P = 0.05), aged <6 months at diagnosis (P < 0.01).

CONCLUSION

Pulmonary vein stenosis of ex-premature infants is a complex problem with poor survival, delayed diagnosis, and unsatisfactory treatment. The lack of concordance in twins suggests epigenetic or environmental factors may play a role in the development of pulmonary vein stenosis. In ex-premature infants with pulmonary hypertension and bronchopulmonary dysplasia a focused echocardiographic assessment of the pulmonary veins is required with further imaging if the echocardiogram is inconclusive.