Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post recent median sternotomy and aortic valve replacement . Stable postoperative appearance of cardiomediastinal contours . Persistent bilateral retrocardiac atelectasis and small - to - moderate bilateral pleural effusions . No visible pneumothorax .
    OUTPUT:
    
Persistent bibasilar atelectasis and pleural effusions .