NPPB and pulmonary arterial hypertension: In our study, the analyses of functional status, 6MWT, or NTproBNP, as well as echocardiography, all pointed to serious clinical impairment and severe PAH but were not able to show differences between the two groups, although the difficulty in precisely analyzing all of the right-ventricular morphological and functional features with standard echocardiographic methods may limit the results.