Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Subtle increase in interstitial markings bilaterally may be due to technique or chronic lung disease / fibrosis . No focal consolidation is seen . No pleural effusion or pneumothorax is seen . The cardiac and mediastinal silhouettes are stable . The patient is status post median sternotomy and cardiac valve replacement . .
    OUTPUT:
    
No focal consolidation to suggest pneumonia .