Chronic thromboembolic pulmonary hypertension in Austria and Japan

Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by one or more of the following features: intraluminal thrombus organization, fibrous stenosis, and complete obliteration of major pulmonary arteries, amenable to significant improvement by pulmonary endarterectomy (PEA) or balloon pulmonary angioplasty, and medical treatments with vasodilators. Because treatment practices and outcomes differ in Europe versus Japan, we hypothesized that population-based characteristics of pulmonary vascular phenotypes may exist in Austria compared with Japan. The objectives of this study were to analyze clinical characteristics, hemodynamics, and PEA specimens in consecutive patients with CTEPH undergoing PEA in Austria and Japan.

Clinical features, hemodynamics, and PEA specimens were collected and analyzed in patients with CTEPH undergoing PEA, and clinical features and hemodynamics were collected and analyzed in patients with not-operated CTEPH and in patients with nonthromboembolic pulmonary arterial hypertension.

Apart from key differences between Austrian and Japanese patients regarding body size, lung function vital capacity, cardiac output, and serum high-density lipoprotein levels, Austrian patients were more likely to be obese, have greater hematocrits and greater white blood cells counts, greater C-reactive protein levels, and significantly elevated serum myeloperoxidase levels compared with Japanese patients with CTEPH. Analysis of PEA specimens demonstrated more proximal thrombus and more fresh red thrombus components in Austrian patients.

This study documents an inflammatory thrombotic phenotype in Austrian compared with Japanese patients with CTEPH that may be a determinant of differential treatment outcomes.