Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are overinflated with diffuse hyperlucency , flattening of the diaphragm , and widening of the retrosternal clear space . Changes of median sternotomy and coronary artery bypass grafting are seen . Heart size is top normal . The aorta is tortuous and calcified . There are no pleural effusions or pneumothorax .
    OUTPUT:
    
COPD . No acute cardiopulmonary process .