1. 1Cardio-Thoracic Department, Pneumology and Respiratory Intensive Care Unit, “Carlo Poma” Hospital, Mantova, Italy
2. 2Pneumology Department, Clinic Institute of Thorax (ICT), Hospital Clinic of Barcelona, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) - University of Barcelona (UB), Barcelona, Spain
3. 3Pneumology Department, Hospital Universitario y politecnico La Fe, CIBERES, Valencia, Spain
4. 4Centre for Respiratory Medicine, Royal Free Campus, University College London Medical School, London, United Kingdom