Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart size is top normal in with evidence of prior CABG . Normal postoperative changes are noted overlying the sternum and retrosternum with no air - fluid levels seen in the retrosternal space . No focal opacities , pleural effusions , pneumothorax , or pulmonary edema are seen .
    OUTPUT:
    
No evidence of sternal instability .