Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A linear opacities in the left lung base have decreased since ___ , probably atelectasis . No pleural effusion or pneumothorax is identified . The cardiac and mediastinal contours are normal . There is a replaced mitral valve and a tricuspid annuloplasty . The third median sternotomy wire has been fractured since ___ . Clips project over the right upper mediastinum .
    OUTPUT:
    
Mild left basal atelectasis or linear scarring . No pneumonia