Table 2.

Revised Clinical Classification of Pediatric Pulmonary Hypertension as Proposed by 2018 World Symposium on Pulmonary Hypertension, Nice, France. Pediatric Task Force

Group 1. Pulmonary arterial hypertension (PAH)	1.1 Idiopathic PAH (IPAH) 1.2. Heritable PAH (HPAH) 1.3. Drug and toxin related PAH 1.4. Associated PAH
		1.4.1. PAH associated with CTD 1.4.2. PAH associated with HIV infection 1.4.3. PAH associated with portal hypertension 1.4.4. Congenital heart disease 1.4.5. Schistosomiasis
	1.5. PAH long-term responders to CCBs 1.6. PAH with overt features of venous/capillaries (PVOD/PCH) involvement 1.7. Persistent PH of the newborn (PPHN) syndrome
Group 2. PH due to left heart disease	2.1. LV systolic dysfunction 2.2. LV diastolic dysfunction 2.3. Valvular disease 2.4. Congenital/acquired left heart inflow/outflow tract obstruction and congenital cardiomyopathy–pulmonary vein stenosis (isolated or associated with BPD), cor triatriatum, obstructed Total Anomalous Pulmonary Venous Return (TAPVR), Mitral/aortic stenosis (including supra/subvalvular) and coarctation of aorta
Group 3. PH due to lung disease and/or hypoxia	3.1. Chronic obstructive pulmonary disease 3.2. Interstitial lung disease 3.3. Other pulmonary diseases with mixed restrictive and obstructive pattern 3.4. Sleep-disordered breathing 3.5. Alveolar hypoventilation syndromes 3.6. Long-term exposure to high altitudes 3.7. Developmental lung diseases
		Bronchopulmonary dysplasia Congenital Diaphragmatic Hernia Down syndrome Alveolar capillary dysplasia with “misalignment of veins” (FOXF1) Lung hypoplasia, acinar dysplasia Surfactant deficiency TTF-1/NKX2-1 TBX4 Pulmonary interstitial glycogenesis Pulmonary alveolar proteinosis Pulmonary lymphangiectasia
Group 4. PH due to pulmonary artery obstructions	4.1. Chronic thromboembolic PAH 4.2. Pulmonary artery obstructions either congenital or acquired after cardiac surgery
Group 5. PH due to unclear/multifactorial mechanisms	5.1. Hematological disorders: chronic hemolytic anemia, myeloproliferative disorders, splenectomy 5.2. Systemic disorders: sarcoidosis, pulmonary histiocytosis, lymphangioleiomyomatosis 5.3. Metabolic disorders: glycogen storage disease, Gaucher disease, thyroid 5.4. Others: tumor obstruction, fibrosing mediastinitis, chronic renal failure, complex CHD–unoperated or operated single ventricle, pulmonary atresia with ventricular septal defect and major aorto-pulmonary collaterals, hemitruncus, absent pulmonary artery and isolated pulmonary artery of ductal origin

CTD, connective tissue disease; HIV, human immunodeficiency virus; CCB, calcium channel blocker; PVOD, pulmonary venous obstructive disease; PCH, pulmonary capillary hemangiomatosis; LV, left ventricle; BPD, bronchopulmonary dysplasia; CHD, congenital heart disease.

Adapted, with permission, from Rosenzweig EB, et al., 2019 (506).