Abstract
Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by pulmonary hypertension caused by nonresolving thromboemboli of the pulmonary artery. However, up to 40% of CTEPH patients have had no clinically apparent acute pulmonary embolic episodes. In addition, both a female predominance and an association of HLA with CTEPH unrelated to deep vein thrombosis are observed in Japan, thus suggesting this condition to be a type of pulmonary vasculopathy. The key for making an accurate diagnosis is to consider CTEPH in any patients with dyspnea on exertion. Perfusion scans provide an excellent noninvasive tool for distinguishing between pulmonary arterial hypertension (PAH) and CTEPH, while CT angiography is useful for differentiating arteritis, tumor, and a congenital anomaly of the pulmonary artery from CTEPH. Pulmonary angiography (PAG) is still considered the gold standard for evaluating CTEPH. No subpleural perfusion in any segments by PAG with high pulmonary vascular resistance is might be related to small vessel disease, thus resulting in a poor outcome after surgery. Recent data suggest a potential therapeutic benefit of antiproliferative therapy for cells isolated from endarterectomized tissue.