Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable AP chest radiograph . Median sternotomy wires are intact . Prosthetic aortic and mitral valves are in unchanged position . The lungs are clear and there is no pleural effusion or pneumothorax . The cardiomediastinal silhouette is stable .
    OUTPUT:
    
No acute cardiopulmonary process .