Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post aortic valve replacement . There has been no significant change in dilatation of the aorta . The mediastinal and hilar contours appear unchanged . The heart is at the upper limits of normal size . The lungs appear clear . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
Stable appearance of the chest .