Charts of patients were retrieved and data concerning demographics, Dana Point/WHO classification, WHO functional class (FC), 6-MWD, right ventricular systemic pressure (RVSP), CI, mPAP, RAP, PVR, systemic vascular resistance (SVR), SvO2, PaCO2, fibrinogen plasma concentrations, CRP concentrations, NT-proBNP concentrations, observation time and mortality was extracted wherever possible.