Precapillary pulmonary hypertension associated with connective tissue disease

resting mean pressure in the pulmonary artery of \> 24 mmHg

resting mean pulmonary capillary wedge pressure (PCWP) of \< 16 mmHg

age 18 to 80 years

women of childbearing potential must have a negative pregnancy test (ß-HCG in urine) and must use effective methods of contraception

women must not be breastfeeding

ability to understand and sign the informed consent, correctly signed informed consent

VasoREACTivity Testing With Intravenous SILdenafil in Patients With Precapillary Pulmonary Hypertension