Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Re-identified are multiple median sternotomy wires as well as the prosthetic aortic cardiac valve . The cardiomediastinal silhouette is at the upper limits of normal or slightly enlarged . The hila are grossly unremarkable . No focal consolidation . There is no pulmonary vascular congestion or pulmonary edema . There is no pneumothorax . There are small bilateral pleural effusions .
    OUTPUT:
    
Heart size is at the upper limits of normal or slightly enlarged . Sternotomy wires and prosthetic valve noted . Small bilateral posterior pleural effusions , new compared with ___ . Upper zone redistribution , but no overt CHF . Although a small infiltrate associated with the effusions can not be excluded , elsewhere , no focal infiltrate identified .