Volatile Organic Compounds (VOCs) as a Biomarker in Immune-mediated Pulmonary Arterial Hypertension (PAH)

Aim: to investigate the role of inflammation and auto-immunity in pulmonary arterial hypertension by using the profile of volatile organic compounds. Hypothesis: first, the investigators hypothesize that at time of diagnosis the VOC profiles will discriminate patients with PAH-CTD and idiopathic PAH (IPAH) from patients with systemic sclerosis or systemic lupus erythematosus (CTD) without PAH, supporting the contention that there is a overlapping inflammatory and auto-immune pathway in PAH. During follow-up, the investigators will measure the VOC profiles of patients in all three groups who will be treated according standard clinical care. The hypothesis is that VOC profiles are affected by therapy.