Abstract
Pulmonary hypertension is a syndrome characterized by a mean pulmonary artery pressure which exceeds 25 mm Hg. Chronic thromboembolic pulmonary hypertension (CTEPH) represents its third leading cause.
CTEPH is caused by both persistent thrombotic obstruction of the pulmonary arteries and peripheral vascular remodelling. As a result, pulmonary vascular resistance increases, leading to right ventricular overload and right-sided heart failure.
Ventilation/perfusion lung scintigraphy is a crucial imaging modality for detecting CTEPH. CT angiography and conventional angiography along with invasive haemodynamic assessment are used for the definitive diagnosis of the disease.The majority of patients with CTEPH are treatable and often curable with surgical pulmonary endarterectomy (PEA).
Patients with inoperable CTEPH due to peripheral involvement and those with persistent pulmonary hypertension after PEA are potential candidates for specific vasodilator therapy. Previous randomized clinical trials have failed to show a beneficial effect of iloprost, sildenafil, and bosentan in these patients.
Riociguat, a soluble guanylate cyclase stimulator, is the first drug the efficacy of which has been demonstrated for this indication. In selected cases, treatment also involves balloon angioplasty and lung transplantation.