Balloon pulmonary angioplasty in patients with chronic thromboembolic pulmonary hypertension in Greece: data from the Hellenic Pulmonary Hypertension Registry - Karyofyllis, P; Demerouti, E; Giannakoulas, G; Hellenic Society for the Study of Pulmonary Hypertension HSSPH (J Clin Med, 2022)