Chronic thromboembolic pulmonary hypertension in Austria and Japan

Abstract Objectives 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 (BPA), 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 CTEPH patients undergoing PEA in Austria and Japan. Methods Clinical features, hemodynamics, and PEA specimens were collected and analyzed in CTEPH patients undergoing PEA, and clinical features, hemodynamics were collected and analyzed in patients with not-operated CTEPH and in patients with non-thromboembolic pulmonary arterial hypertension (PAH). Results Apart from key differences between Austrian and Japanese patients regarding body size, lung function vital capacity, cardiac output and serum HDL levels, Austrian patients were more likely to be obese, had higher hematocrits and higher white blood cells counts, higher C-reactive protein levels and significantly elevated serum myeloperoxidase levels, compared with Japanese CTEPH patients. Analysis of PEA specimens demonstrated more proximal thrombus, and more fresh red thrombus components in Austrian patients. Conclusions This study documents an inflammatory thrombotic phenotype in Austrian compared with Japanese CTEPH patients that may be a determinant of differential treatment outcomes.