Biomarker measurement was performed at baseline and follow-up in the CTEPH cohort, prior to each BPA in the BPA cohort and once in the control group.<h4>Results</h4>The median PAPP-A level was slightly higher (p = 0.05) in CTEPH patients [13.8 (11.0-18.6) mU/L], than in the control group [12.6 (8.6-16.5) mU/L], without a difference between the BPA and PEA group (p = 0.437) and without a correlation to mean pulmonary artery pressure (p = 0.188), pulmonary vascular resistance (p = 0.893), cardiac index (p = 0.821) and right atrial pressure (p = 0.596). This evidence concerns the gene PAPPA and chronic thromboembolic pulmonary hypertension.