NPPB and idiopathic interstitial pneumonia: In fact, the occurrence of PH in IPF may be characterized by increased dyspnoea, reduction of gas exchange at rest, markedly low DLCO, rapid desaturation upon exercise, high brain natriuretic peptide (BNP) levels, right heart dilation on chest radiography, impaired quality of life, lower exercise tolerance, and greater supplemental oxygen requirements [107].