Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post median sternotomy and CABG . Moderate enlargement of cardiac silhouette is unchanged . Mediastinal contours stable . Mild pulmonary vascular congestion persists , and may be slightly improved compared to the previous exam . No pleural effusion or pneumothorax is seen . There is minimal atelectasis at the lung bases . Multilevel degenerative changes are noted in the thoracic spine .
    OUTPUT:
    
Mild pulmonary vascular congestion and mild bibasilar atelectasis .