1 Pulmonary Unit, Cardiothoracic and Vascular Department, Pisa University Hospital, Pisa, Italy. Electronic address: f.pistelli@ao-pisa.toscana.it.
2 Pulmonary Unit, Cardiothoracic and Vascular Department, Pisa University Hospital, Pisa, Italy; Department of Surgical, Medical, and Molecular Pathology and Critical Care Medicine, University of Pisa, Pisa, Italy.