Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post aortic valve replacement . Dilatation of the aortic knob is unchanged from multiple priors dating back to ___ . There are surgical clips overlying the right upper outer hemithorax . The lungs are well expanded and clear . A small retrocardiac opacity along the inferior left margin of the heart is not confirmed in the lateral view and is felt to represent summation of structures . There is cardiomegaly , stable . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
No evidence of acute cardiopulmonary process . Unchanged appearance of the enlarged aortic arch dating back to ___ .