Why Is Pulmonary Endarterectomy Underused in Japan? Epidemiology, Genetics, and a Practical Operability Framework

Chronic thromboembolic pulmonary hypertension (CTEPH) is a complication of pulmonary embolism that is characterized by chronic obstruction of pulmonary arteries because of organized thrombi. Pulmonary endarterectomy (PEA) is the primary treatment of choice for CTEPH, which aims to clear the pulmonary arteries as completely as possible to decrease right ventricular afterload, thereby improving pulmonary hypertension (PH). PEA is a complex surgical procedure involving cardiopulmonary bypass and deep hypothermic circulatory arrest. Although it provides excellent outcomes, it is associated with frequent complications, including lung reperfusion injury, endobronchial hemorrhage, and persistent PH. Therefore, patients with CTEPH need to be referred to specialized centers. Germany performs approximately 150 PEA procedures annually. However, in Japan, the availability of PEA facilities is limited. The present study aims to delineate the differences in CTEPH management between Japan and Germany, evaluate the underlying reasons for the limited implementation of PEA in Japan, and underscore the need for specialized assessment and referral of patients who are eligible for PEA. The limited utilization of PEA in Japan appears to be attributable not to underestimation of the procedure itself, but rather to anatomical and institutional constraints.