NPPB and pulmonary arterial hypertension: By use of the COMPERA risk score (6MWD, WHO-FC, NT-proBNP, RA pressure, cardiac index and mixed oxygen saturation), survival and TTCW were significantly stratified for PAH without (p = 0.003 and p = 0.038), but not with comorbidities (p = 0.435 and p = 0.637).