FIGURE 2.

The risk factors of and pathogenic mechanism underlying CTEPH. The pathological conditions, including genetic mutation, inflammation-associating endothelial dysfunction, recurrent thrombosis, and reduced thrombolytic activity, result in the imbalance between thrombosis and thrombolysis, which causes insolubility and organization of the thrombi in pulmonary arteries. As the thrombi block the pulmonary arteries, the pulmonary circulation is diverted to the unblocked ones, where intravascular pressure and shear stress is consequently elevated. Both the thrombus-mediated blockade of pulmonary arteries and the diverted blood-mediated elevation in mechanical stress lead to vascular remodeling, increased pulmonary vascular resistance, progressive PH. CTEPH, chronic thromboembolic pulmonary hypertension; PTE, pulmonary thromboembolism; PH, pulmonary hypertension.