1. 6th Respiratory Department, Sotiria Chest Diseases Hospital, Athens, Greece
2. Department of Pneumology, Institut Clinic del Tórax, Hospital Clinic of Barcelona - Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), University of Barcelona (UB) - SGR 911 - Ciber de Enfermedades Respiratorias (Ciberes), Barcelona, Spain