NPPB and chronic thromboembolic pulmonary hypertension: This study aimed to establish an RV dysfunction score using the four RV echocardiographic parameters (TAPSE, S′, RVFAC, and RV-MPI) to clarify the clinical characteristics on admission in patients with CTEPH and to compare the RV dysfunction score with parameters such as symptoms of World Health Organization (WHO) functional class, hemodynamics, exercise capacity [6-min walk test (6MWT) and cardiopulmonary exercise test (CPET)], and plasma brain natriuretic peptide (BNP) level used for risk assessment in patents with CTEPH.