Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable AP upright chest radiograph provided . Midline sternotomy wires and mediastinal clips are again noted . The previously noted dialysis catheter has been removed . There is severe pulmonary edema , increased from prior exam . Retrocardiac opacity could represent pleural effusion , though superimposed pneumonia is difficult to exclude . Followup radiograph post-diuresis is advised . The heart remains enlarged . Mediastinal contour is stable . Hilar vascular engorgement is present . Bony structures are intact .
    OUTPUT:
    
Pulmonary edema , cardiomegaly , probable left pleural effusion . Post - diuresis films may be helpful to exclude underlying left lower lobe pneumonia .