In left heart disease, impaired exercise capacity [29] and poor prognosis [30,31,32,33] are associated with elevated NT-proBNP levels, while their correlate is associated with right ventricle dysfunction and increased mortality in patients with idiopatic PAH or with CTEPH (chronic thromboembolic PAH) [34,35,36,37]. Here, NPPB is linked to pulmonary arterial hypertension.