Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post median sternotomy , aortic valve surgery , and CoreValve placement . The appearance of the CoreValve is similar to the prior post - procedural radiograph . The heart size is normal . The mediastinal contours are remarkable for tortuosity of the thoracic aorta and a large hiatal hernia . Patchy and linear opacities are present at the lung bases , and note is made of small pleural effusions bilaterally .
    OUTPUT:
    
1 . Bibasilar opacities are most suggestive of atelectasis , but followup radiographs may be helpful to exclude coexisting pneumonia or aspiration in the right lower lobe . 2 . Small pleural effusions . 3 . Large hiatal hernia .