NPPB and heart failure: The classification system of New York Heart Association (NYHA) is used for rapid clinical assessment of cardiac function status, and it is considered to be a good way for dividing the cardiac function status and predicting the prognosis of the patients by dichotomy.[1,2] NT-proBNP is currently the optimal biochemical indicator for the diagnosis and management of heart failure.[3,4] Currently, the classification system of NYHA and NT-proBNP are widely used in clinical practice to evaluate the function of the right heart in patients with pulmonary arterial hypertension.