Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Patient is status post median sternotomy and CABG . The heart remains mildly enlarged . The aortic knob remains calcified . The mediastinal and hilar contours are stable . Pulmonary vascularity is normal . Linear opacity in left lung base is compatible with atelectasis . No focal consolidation , pleural effusion , or pneumothorax is identified . There are mild degenerative changes in the thoracic spine .
    OUTPUT:
    
Minimal left basilar atelectasis . No pneumothorax or acute osseous abnormality visualized .