Epidemiology and Pathophysiology of Chronic Thromboembolic Pulmonary Hypertension: Risk Factors and Mechanisms.

Chronic thromboembolic pulmonary hypertension (CTEPH) occurs when thromboemboli travel to the pulmonary vasculature, fail to resolve, and cause elevated pulmonary arterial pressure. Untreated, this disease leads to progressive right heart failure and death. It develops in approximately 1% to 5% of patients who suffer an acute pulmonary embolism (PE) and has an overall incidence of 3 to 30 per million in the general population. While it is not entirely evident why most but not all people are able to clear this clot burden, there are known risk factors for the development of CTEPH. These include signs of right heart strain at the time of incident PE, inherited coagulopathies, inflammatory conditions, hypothyroidism, and a history of splenectomy. Since CTEPH can be treated both surgically and medically, it is critical to understand the pathophysiology of the disease so affected patients can be identified and diagnosed appropriately.