Table 2. Spectrum of patients with Ipc-PH according to clinical classification.

Clinical classification	Ipc-PH n = 641
Group 1 PH–PAH
• Idiopathic/Heritable	220 (34%)
• associated with CTD	62 (10%)
• associated with CHD	52 (8%)
Group 3 PH–Lung disease/Hypoxia	140 (22%)
Group 4 PH–CTEPH	130 (20%)
Group 5 PH–Unclear and/or multifactorial mechanism	37 (6%)

Values are expressed as n (%). NS–non-significant. Ipc-PH–isolated pre-capillary pulmonary hypertension; PH–pulmonary hypertension; PAH–pulmonary arterial hypertension; CTD–connective tissue disease; CHD–congenital heart disease; CTEPH–chronic thrombembolic pulmonary hypertension.