To test independence of fibrinogen plasma concentrations from demographical data and disease severity a multivariate analysis including age, sex, WHO functional class, fibrinogen and the hemodynamic and functional parameters identified in univariate analysis (RAP, mPAP, PVR, CI, and 6-MWD) was performed. Here, fibrinogen was confirmed as an independent marker of haemodynamic impairment as RAP and mPAP were independently associated with fibrinogen concentrations (Table 3, right columns). In addition, PVR and CI showed a non-significant trend to be associated with fibrinogen concentrations.