Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Mechanical mitral valve in situ . Cardiomediastinal shadow is enlarged with a prominent left auricle , but is unchanged . Left lower lobe atelectasis appears improved . Small to moderate bilateral pleural effusions are slightly improved compared to prior . No pulmonary edema . Spondylotic changes of the thoracic spine .
    OUTPUT:
    
Mild interval improvement in the left lower lobe atelectasis and small to moderate bilateral pleural effusions .