Using a preclinical animal model mimicking the heterogeneous ventilation perfusion patterns in the lung of patients with secondary PH forms, we evaluated the “desaturation-potential” of bosentan, sildenafil, and the sGC stimulators BAY 41–8543 and riociguat (currently in clinical development for PAH and chronic thromboembolic pulmonary hypertension [CTEPH]). Here, SGCB is linked to chronic thromboembolic pulmonary hypertension.