NPPB and pulmonary arterial hypertension: The low-stability trajectory and the early-remission trajectory were related to a similar positive prognosis (no all-cause death or re-hospitalization for worsening PAH occurred), while the occurrence of all-cause death or re-hospitalization for worsening PAH increased sharply in patients with a delayed-remission trajectory, indicating that an early remission of NT-proBNP within 3 months from baseline, but not a delayed remission of NT-proBNP after 6 or 9 months from baseline, could improve the prognosis.