Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low . The cardiomediastinal silhouette and pulmonary vasculature are unchanged since the prior examination . The aorta is tortuous . The patient has undergone prior median sternotomy and CABG . Wires are intact and well aligned . There is no focal consolidation . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
Stable appearance of the mediastinum . No acute intrathoracic abnormality .