Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There are low lung volumes . Left base opacity is again seen which could be due to pleural effusion and overlying atelectasis , consolidation due to pneumonia or / and aspiration not excluded . Pulmonary vascular congestion persists . The patient is status post median sternotomy and aortic valve replacement . Cardiac and mediastinal silhouettes are stable .
    OUTPUT:
    
Aside from subtle decrease in opacity in the left mid lung , there has been no significant interval change . Persistent pulmonary vascular congestion and left basilar opacity . Stable cardiac and mediastinal silhouettes .