Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable upright AP views of the chest were provided . Midline sternotomy wires and mediastinal clips again noted . Patient is known to have a background of emphysema though there is superimposed pulmonary edema . Trace bilateral pleural effusions are seen . Overall no change from prior study from approximately three hours earlier . Bony structures appear intact .
    OUTPUT:
    
Findings compatible with congestive heart failure superimposed on a background of emphysema . No change from prior from three hours ago .