Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post median sternotomy and CABG . Mild enlargement of cardiac silhouette is unchanged . The aortic knob is calcified . Mediastinal and hilar contours are otherwise within normal limits . Lungs are clear . The pulmonary vasculature is normal . Trace right pleural effusion appears decreased in size compared to the prior exam . Left costophrenic angle is not completely included in the field of view , though no large left - sided pleural effusion is demonstrated . No pneumothorax is seen . There is no free air visualized under the diaphragms .
    OUTPUT:
    
No subdiaphragmatic free air is identified . Trace right pleural effusion , decreased in size compared to the previous study .