Of these, the following patients were excluded from this study: patients with previous history of PAH or systolic PAP (sPAP) ≥ 50 mmHg at rest [1], severe restrictive lung disease (forced vital capacity < 80% of the predicted value), left ventricular (LV) systolic dysfunction (LV ejection fraction < 60%), LV diastolic dysfunction [the ratio of peak early diastolic mitral inflow velocity (E) and peak early diastolic mitral annular velocity (e′); E/e′ ≥ 15],