Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest were obtained . The patient is status post CABG with median sternotomy and intact sternal wires . Mild enlargement of the cardiac silhouette is similar to the prior study . Since the prior study , there is improved aeration of the lungs with mild bibasilar atelectasis . No overt pulmonary edema . Aortic tortuosity is unchanged .
    OUTPUT:
    
Bibasilar atelectasis . No overt pulmonary edema .