Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest are compared to previous exam from ___ . Compared to prior , there has been no significant interval change . Postoperative changes from median sternotomy and mitral valve prosthesis are again seen . Linear opacity at the left lung base most suggestive of atelectasis . Elsewhere the lungs are clear . There is no effusion . Cardiomediastinal silhouette is otherwise unremarkable . Osseous and soft tissue structures are unchanged .
    OUTPUT:
    
No acute cardiopulmonary process .