NPPB and pulmonary arterial hypertension: There are several clinical, laboratory and echocardiographic parameters that have been shown to be associated with higher risk of death in pediatric pulmonary hypertension, such as: Word Health Organization (WHO) functional class 3/4 [1, 4, 6], elevated levels of brain natriuretic peptide (BNP) [1, 7, 8] or evidence of right ventricular (RV) failure [1].