Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post midline sternotomy and mitral valve replacement . The lungs again appear hyperexpanded , but remain clear . Mild enlargement of the cardiac silhouette is not significantly changed . The mediastinal contours are unchanged , including tortuosity of the descending thoracic aorta . There are no pleural effusions . No pneumothorax is seen .
    OUTPUT:
    
1 . No acute cardiac or pulmonary process . 2 . Unchanged mild cardiomegaly .