NPPB and heritable pulmonary arterial hypertension: The reductions in NT-proBNP at weeks 12 and 24 were significant in both CTD-PAH (p < 0.001) and IPAH/HPAH (p < 0.001) subgroups, but the reduction in NT-proBNP at weeks 12 and 24 was greater in the CTD-PAH subgroup compared with the IPAH/HPAH subgroup (Table 2).