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 portable chest examination of ___ . Status post sternotomy related to bypass surgery as before . Heart size remains normal . Thoracic aorta generally widened and elongated but no interval change is noted . The previously described right - sided mass in the right superior mediastinum occupying the right tracheobronchial angle remains unchanged . No pneumothorax has developed . As before , there are pulmonary findings compatible with COPD but the on previous examination identified left - sided basal infiltrates and linear atelectasis have clearly regressed . No new abnormalities are seen , and the lateral and posterior pleural sinuses are free from any fluid accumulation .
    OUTPUT:
    
Stable cardiovascular , pulmonary findings , however , previously identified density on left base has regressed suggesting that pulmonary event may have been caused by an aspiration .