Invasive hemodynamic evaluation showed suprasystemic PAH and marked acute vasoreactivity (PAP 127/103/83 mmHg, PVRi 23.48 WU·m<sup>2</sup> and PVR/SVR ratio 1.59 at baseline vs. PVRi 5.89 WU·m<sup>2</sup> and PVR/SVR ratio 0.93 under O<sub>2</sub>/NO).
Patients were classified as PAH if echocardiographic systolic pulmonary artery pressure (sPAP) ≥50 mmHg or right heart catheterization (RHC) mean PAP ≥25 mmHg.
In the RHC subgroup (n=28), mean (m)PAP and pulmonary vascular resistance at 50 W increased significantly (p=0.02 and p=0.002, respectively), but resting mPAP was unchanged.Scleroderma patients without PAH develop a mild but significant deterioration of pulmonary exercise haemodynamics and exercise capacity over a 4-year follow-up period, indicating a progression of pulmonary vascular disease.