Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single AP view of the chest provided . Patient is status post median sternotomy . Wires are intact and properly aligned . Patient is status post aortic valve replacement . Lungs are well inflated and grossly clear . No pneumothorax is definitively seen . A left pigtail catheter projects over the costophrenic angle . A minimal left pleural effusion is mildly improved . Hilar and cardiomediastinal contours are normal .
    OUTPUT:
    
1 . A minimal , left pleural effusion is mildly improved from ___ . 2 . The tiny apical pneumothorax on the prior examination is not definitively seen .