Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral chest views were obtained with patient in upright position . There is status post sternotomy and the metallic component of a porcine valve prosthesis is identified in mitral valve position . Cardiac enlargement is very mild , but the left atrial contours are identified both in frontal and lateral view and suggests mild enlargement of the left atrium . Pulmonary vasculature , however , is not congested and no signs of acute infiltrates are present . Rather low positioned and somewhat flattened diaphragms are noted , coinciding with increased translucency of the lung bases suggestive of some degree of COPD . There is no evidence of any pleural effusion and no signs of pneumothorax in the apical area .
    OUTPUT:
    
Status post mitral valve replacement . No evidence of significant pulmonary congestion . No signs of pneumothorax but some general pulmonary findings suggestive of COPD .