2 Indications and current treatments
2.1 Chronic thromboembolic pulmonary hypertension is a progressive disease. It is caused by obstruction of the pulmonary arteries (from main to subsegmental levels) by pulmonary emboli that have not resolved but which have become organised. This causes narrowing of the pulmonary arteries, an increase in the resistance to blood flow and a rise in pressure within the pulmonary arteries. Progression of pulmonary hypertension may occur because of gradual remodelling of unobstructed pulmonary vasculature in response to the haemodynamic changes.
2.2 Early symptoms include chest pain, shortness of breath, fatigue, dizziness, peripheral cyanosis and oedema. If left untreated, chronic thromboembolic pulmonary hypertension often leads to right heart failure and ultimately death.
2.3 Medical treatment includes anticoagulants to prevent recurrent venous thromboembolism and in‑situ pulmonary artery thrombosis. Vasodilators may be used to reduce pulmonary hypertension. Pulmonary endarterectomy is a surgical procedure that aims to remove the obstructing thromboembolic material. However, the procedure may not be suitable for all patients because of comorbidities or because smaller peripheral pulmonary arteries are affected.