Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: As before , the patient is status post midline sternotomy and CABG , with intact sternotomy wires . There is minimal left lower lung scarring , along the costophrenic angle , unchanged . The lungs are otherwise clear . The heart size is top normal . The mediastinal contours are normal . There are no pleural effusions . No pneumothorax is seen . Multilevel degenerative changes of the thoracolumbar spine are noted .
    OUTPUT:
    
No acute cardiac or pulmonary process .