4. Clinically significant pulmonary hypertension documented on right heart catheterization (i.e., right ventricular systolic pressure of >50 mm Hg and/or mean PAP ≥30 mm Hg) pulmonary pressure or echocardiographic evidence of PAH (if echo cardiographic systolic pressure ≥ 55 mmHg) or FVC/DLCO ratio >1.6 on pulmonary function testing