Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post median sternotomy and mitral valve replacement . Stable postoperative appearance of cardiomediastinal contours and sternal wires . Improving bibasilar atelectasis . Persistent small left pleural effusion and interval resolution of small right pleural effusion . Possible splenic enlargement in left upper quadrant .
    OUTPUT:
    
Improving bibasilar atelectasis and resolution of small right pleural effusion . Persistent small left pleural effusion .