Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac and mediastinal contours are somewhat difficult to assess owing to persistent opacification of the right lower hemithorax . The patient is status post aortic valve replacement using an endoluminal approach . A moderate hiatal hernia is noted , similar to prior findings . Opacification of the right lower hemithorax which probably relates to elevation of the right hemidiaphragm , atelectasis , and possibly a pleural effusion , appears very similar to both prior studies without clear change . The right acromioclavicular joint is again widened and irregular . Moderate incompletely characterized degenerative changes affect each shoulder . The bones appear demineralized .
    OUTPUT:
    
Stable appearance of the chest . No definite acute process . Suspicion for persistent pleural effusion and atelectasis at the right lung base . Hiatal hernia .