Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Patient is status post median sternotomy and cardiac valve replacement . The lungs remain hyperinflated , suggesting chronic obstructive pulmonary disease . No focal consolidation is seen . There is no pleural effusion or pneumothorax . The cardiac silhouette remains moderately enlarged . Mediastinal contours are stable . No pulmonary edema is seen .
    OUTPUT:
    
No acute cardiopulmonary process . No significant interval change given differences in patient positioning .