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

 1. PAH-CTD patients, inclusion criteria:

 -  classification as definite systemic sclerosis or systemic lupus erythematosus
 according to respectively the ACR-EULAR criteria (16) and SLICC criteria (17)

 -  minimal age of 18 year

 -  diagnosis of pulmonary arterial hypertension: mean pulmonary artery pressure
 (mPAP) of ≥25 mmHg, pulmonary capillary wedge pressure (PCWP) ≤15 mmHg, and a
 pulmonary vascular resistance (PVR) ≥240 dynes.s.cm-5 measured by right heart
 catherization.

 2. IPAH patients, inclusion criteria:

 -  diagnosis of pulmonary arterial hypertension: mean pulmonary artery pressure
 (mPAP) of ≥25 mmHg, pulmonary capillary wedge pressure (PCWP) ≤15 mmHg, and a
 pulmonary vascular resistance (PVR) ≥240 dynes.s.cm-5 measured by right heart
 catherization.

 -  no family history of PAH

 -  triggering factor is excluded: connective tissue disease, drugs or toxins, human
 immunodeficiency virus, congenital heart disease, portal hypertension,
 schistosomiasis (2)

 -  minimal age of 18 year

 3. SSc and SLE (CTD) patients without PAH, inclusion criteria:

 -  classification as definite systemic sclerosis or systemic lupus erythematosus
 according to respectively the ACR-EULAR criteria (16) and SLICC criteria (17)

 -  minimal age of 18 year

 -  no signs of PAH at screening visit

 Exclusion Criteria:

 -  active or treated malignancy

 -  tuberculosis or hepatitis B/C infection in case of start immunosuppressive therapy

 -  need to start immediately with therapy

 -  already use of immune suppression