Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest were obtained . The cardiomediastinal silhouette is enlarged , increased since ___ , but similar to ___ . Mitral valve annular calcifications and a coronary artery stent are seen . The lungs are clear without focal or diffuse abnormality . The pulmonary vasculature is unremarkable . No pleural effusion or pneumothorax . Osseous structures are unremarkable . No radiopaque foreign bodies .
    OUTPUT:
    
Mild cardiomegaly , enlarged since ___ , but similar to ___ .