Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiomediastinal silhouette is unchanged with moderate cardiomegaly , a calcified aortic knob , and postsurgical changes status post median sternotomy and aortic valve replacement . The hilar contours are unchanged with evidence suggestive of vascular congestion . Bibasilar atelectasis is again seen and unchanged from ___ study . Surgical clips are again seen in the right upper lobe and remain unchanged in position from previous studies .
    OUTPUT:
    
No acute changes when compared to ___ study .