Abstract
Pulmonary hypertension is a syndrome characterized by increased pressure in the pulmonary artery. Pulmonary artery hypertension (PAH) affects the small pulmonary vessels, thus leading to precapillary pulmonary hypertension and later to right sided heart failure.
Treatment of PAH is dominated by pharmacotherapy. Chronic thromboembolic pulmonary hypertension (CTEPH) is a chronic sequel of acute pulmonary embolism occurring when chronic stenoses and occlusions of pulmonary arteries cause an increase in pulmonary arterial pressure.
Its treatment is mainly surgical (pulmonary endarterectomy - PEA). However, PEA is not suitable for all patients, and pulmonary hypertension can persist even after PEA.
Riociguat is an oral soluble guanylate cyclase stimulator augmenting the effects of nitric oxide (NO) on guanylate cyclase, thus increasing the production of cyclic guanosine monophosphate (cGMP). Riociguat increases cGMP production even independently of NO.
Riociguat has been tested in patients with PAH; its application was associated with significant improvement of functional status, functional class, and hemodynamics and also with decrease of natriuretic peptides. In patients with CTEPH who are not PEA candidates or whose pulmonary hypertension persists following PEA, riociguat is the first available specific therapy - its application is associated with improvements in 6 minute walk test, functional class, hemodynamic parameters, and in natriuretic peptide levels.