Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP single view of the chest has been obtained with patient in semi-upright position . Comparison is made with the next preceding similar study obtained four hours earlier during the same day . The remaining left - sided chest tube advanced from below has now been removed . The left lung remains well aerated without evidence of any pneumothorax or new parenchymal infiltrates . The lateral pleural sinuses are free from any significant fluid accumulation . Within the heart shadow , one can identify the metallic components of an aortic valve prosthesis in ordinary location .
    OUTPUT:
    
No pneumothorax . Satisfactory followup findings .