Chronic thromboembolic pulmonary hypertension
Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare and progressive pulmonary vascular disease that is usually the consequence of prior acute pulmonary embolism. CTEPH usually begins with persistent obstruction of large and/or middle-sized pulmonary arteries by organized thrombi. Failure of thrombi to resolve may be related to abnormal fibrinolysis, and underlying haematological or autoimmune disorders, including splenectomy and antiphospholipid antibodies. Small pulmonary vessel remodelling also contributes to haemodynamic compromise, functional impairment, and disease progression in CTEPH. Small vessel disease can occur in non-obstructed areas as well as downstream from occlusions (possibly because of excessive collateral blood supply from high-pressure bronchial and systemic arteries). The degree of small vessel disease has a substantial impact on the severity of CTEPH and post-surgical outcomes. Surgical, interventional, and medical treatment of CTEPH aim to restore normal flow distribution within the pulmonary vasculature, unload the right ventricle, and prevent or treat small vessel disease.