For the current study, one aim is to identify one or several biomarkers which could predict adverse outcome in PAH. To address this aim, the investigators would like to evaluate the levels of CRP, total cholesterol, HDL-cholesterol, triglycerides, albumin, Lp-PLA2 activity, Thrombin Activatable Fibrinolysis Inhibitor (TAFI) and vitamin D in blood plasma from all patients diagnosed with PAH at the UZ Leuven (Campus Gasthuisberg).