Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Compared to the most recent prior study of ___ , the appearance of the chest is unchanged . The patient is status post median sternotomy with multiple mediastinal surgical clips compatible with prior CABG . A mitral valve prosthesis is unchanged in position or appearance . The cardiac silhouette is mildly enlarged but stable . The mediastinal contours are within normal limits and stable with minimal calcification of the aortic knob . Mild pulmonary vascular congestion is unchanged . No significant pleural effusion is present . On the lateral radiograph , there is opacification along the fissure of the left lung corresponding to left basilar opacification on the frontal radiograph . This finding is unchanged from the prior study and may represent partial lobar collapse or fluid trapped within the fissure . No pneumothorax is detected .
    OUTPUT:
    
Persistent mild edema and left lower lobe atelectasis vs fluid in the fissure . Unchanged from ___ . Bronchial obstruction can not be excluded .