Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post median sternotomy and mitral valve replacement . Pericardial calcifications are again seen , best seen on the lateral view . The cardiac silhouette remains mild to moderately enlarged . Aortic knob calcification is seen . The mediastinal contours are stable . There is slight blunting of the posterior left costophrenic angle which may be due to a trace effusion . No focal consolidation is seen . There is no pneumothorax .
    OUTPUT:
    
Possible trace pleural effusion . Persistently enlarged cardiac silhouette .