Fig. 4

Changes of PVR at rest over 6 months. Ambrisentan patients had on average a lower PVR at 6 months compared to placebo. The mean change of PVR at rest over 6 months in the ambrisentan group was − 0.70 ± 0.78 WU and that in the placebo group was 0.01 ± 0.71 WU. Ambrisentan significantly decreased the PVR at rest over 6 months compared to placebo (p = 0.012)