Gender differences in chronic thromboembolic pulmonary hypertension in Japan.

Background: The predominance of chronic thromboembolic pulmonary hypertension (CTEPH) in females and association of HLA-B*5201 with CTEPH have been reported in Japan. However, the clinical characteristics of female CTEPH remain uncertain. The purpose of the present study is to clarify the clinical phenotype of female CTEPH in Japan.

Methods And Results: The 150 consecutive patients (female 103, male 47; age 52.8+/-12.4 years SD) were admitted to Chiba University Hospital, and diagnosis was confirmed using right cardiac catheterization and pulmonary angiography. Among these patients, 78 underwent pulmonary endarterectomy. Clinical characteristics, pulmonary hemodynamics, extent of central disease and surgical outcome in females were compared with those in males. The female patients were elderly and had less deep vein thrombosis, less acute embolic episodes, better cardiac function, lower arterial oxygen tension and more peripheral thrombi, and showed less improvement through surgery than males. When the patients were identified using HLA-B*5201, HLA-B*5201-positive female patients had less embolic episodes and better cardiac function with lower operative mortality. In contrast, HLA-B*5201-negative female patients had less embolic episodes, and more peripheral thrombi, resulting in less improvement by surgery.

Conclusion: The clinical phenotype of female CTEPH differed from that of male CTEPH. Additionally, gender differences of HLA-B*5201-positive type were dissimilar to those of HLA-B*5201-negative type.