Types, outcomes of pulmonary hypertension differ substantially between children and adults

Among pediatric patients in the Pediatric Pulmonary Hypertension Network, nearly half had group 3 disease, defined as pulmonary hypertension associated with lung disease or hypoxia, researchers reported in the European Respiratory Journal.

The Pediatric Pulmonary Hypertension Network (PPHNet) was launched in 2008 and is a collaborative group of established pulmonary hypertension programs at eight interdisciplinary pediatric centers in North America.

“Despite advances over the past decades, pulmonary hypertension and related pulmonary vascular diseases cause significant morbidity and mortality in diverse neonatal, pulmonary, cardiac, hematologic and other systemic disorders of childhood,” Steven H. Abman, MD, professor in the department of pediatrics and director of the Pediatric Heart Lung Center at the University of Colorado School of Medicine and Children’s Hospital Colorado, told Healio. “Despite the availability of new drug therapies, the long-term outcomes of children with severe pulmonary hypertension can be poor. Although most clinical studies have emphasized studies of adult patients, pulmonary hypertension in pediatrics can be just as devastating and insights into specific age- and disease-specific management strategies are needed to improve outcomes.”

Abman and colleagues analyzed data from 1,475 pediatric patients enrolled in the PPHNet registry. The PPHNet characterized the distribution and clinical features of associated diseases defined by the World Symposium on Pulmonary Hypertension. The five groups of disorders identified to cause pulmonary hypertension were:

• group 1: pulmonary arterial hypertension;
• group 2: pulmonary hypertension associated with left heart disease;
• group 3: pulmonary hypertension associated with lung disease;
• group 4: pulmonary hypertension associated with chronic blood clots in the lungs; and
• group 5: pulmonary hypertension associated with unknown causes.

The most common classifications were group 1 in 45% and group 3 in 49%. In those with group 3 pulmonary hypertension, the most common conditions were bronchopulmonary dysplasia (44%) and congenital diaphragmatic hernia (36%). Among patients with group 1 pulmonary hypertension, 60% had congenital heart disease and 23% had idiopathic PAH.

Pediatric patients categorized as group 3 disease had better disease resolution (HR = 3.1; 95% CI, 2.6-3.7; P < .001), were younger at the time of diagnosis (median age, 0.3 vs. 1.6 years; P < .001) and were more likely to be male (57% vs. 45%; P < .001) compared with those in group 1.

The most common genetic syndrome was Down syndrome in 11% of pediatric patients.

“Despite some similarities, many aspects of pulmonary hypertension in children are distinct from adult pulmonary hypertension. Pediatric pulmonary hypertension is often intrinsically linked to issues of lung growth and development, including many prenatal and early postnatal influences, especially with prematurity, developmental lung disorders, congenital heart disease and other causes. There are marked differences in the epidemiology of pediatric and adult pulmonary hypertension, and there are apparent differences in underlying genetic factors in children with pulmonary hypertension as well,” Abman told Healio.

“This study is one of the most comprehensive studies in the published literature to address the proportion of children with difference causes of pulmonary hypertension and to fully characterize diagnostic strategies, clinical care and late outcomes.”

Abman said the PPHNet researchers will continue to analyze disease-specific features and outcomes.

“Much more research is needed to better identify optimal clinical endpoints, including echocardiographic metrics, biomarkers, functional class, activity (such as with actigraphy), genetic factors and quality of life assessments, to enable more successful clinical trial design and clinical care for our children with pulmonary hypertension,” Abman said. “This current paper provides new and highly detailed information to help launch such studies, and expansion of the PPHNet registry with its accompanying biorepository will provide further information for these studies.”

For more information:

Steven H. Abman, MD, can be reached at steven.abman@cuanschutz.edu.