Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral chest views were obtained with patient in upright position . Analysis is performed in direct comparison with the next preceding similar study of ___ . Status post sternotomy and previous bypass surgery as before . Unchanged appearance of heart size . No evidence of pulmonary vascular congestion with normal appearing right hemithorax . The previously described pleural density blunting the left lateral pleural sinus and obscuring the diaphragm remains rather unchanged . Extension into the posterior pleural sinus also unaltered and no evidence of pneumothorax .
    OUTPUT:
    
Unchanged appearance of previously described pleural effusion during last one week examination interval .