Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Stable slight bilateral lower lung volumes . Mild pulmonary vascular congestion that appears slightly increased from the prior exam . Stable appearance of the cardiomediastinal silhouette with mild cardiomegaly . Stable appearance of the hila . No pleural effusion , focal consolidation , overt pulmonary edema , or pneumothorax . Post-median sternotomy changes are stable . No evidence of pneumoperitoneum .
    OUTPUT:
    
1 . Mild pulmonary vascular congestion compatible with congestive heart failure . 2 . No evidence of free air .