Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: As before , the patient is status post midline sternotomy and CABG . Hyperexpansion of the lungs is longstanding . There is minimal bilateral lower lung scarring / atelectasis . The lungs are otherwise clear . The heart size is normal . The mediastinal contours are normal . Aortic calcifications are noted . Blunting of the posterior costophrenic angles could be due to trace bilateral pleural effusions , not significantly changed . There is no pneumothorax .
    OUTPUT:
    
1 . No acute cardiac or pulmonary findings . 2 . Evidence of COPD . 3 . Possible trace bilateral pleural effusions , unchanged .