Clinical characteristics of adult-onset idiopathic peripheral pulmonary artery stenosis (PPS). Overview of patient backgrounds, imaging findings, site of stenosis in pulmonary angiography, treatment profiles, treatment response and prognosis in this cohort study of patients with adult-onset idiopathic PPS. PAH: pulmonary arterial hypertension; TPA: transcatheter pulmonary angioplasty; mPAP: mean pulmonary arterial pressure; PVR: pulmonary vascular resistance; CI: cardiac index.