Landymore & Howell [15] reported that patients who received internal mammary artery as a graft and underwent chest drainage showed a higher incidence of pleural effusion, atelectasis in the left lower lobe and elevation of the left hemidiaphragm. Moreover, three months after surgery these patients maintained loss of lung volume, areas of atelectasis and pleural effusion. In this study, all patients received internal thoracic artery graft, being that fact uniformed.