Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: As compared to ___ , Swan - Ganz catheter appears unchanged and likely terminates in the main pulmonary artery . The intra-aortic balloon pump terminates approximately 2 .1 cm below the superior aspect of the aortic knob . Right PICC terminates in upper SVC . Previously described rounded opacity in the right base is unchanged . Left retrocardiac atelectasis is minimal . Cardiomegaly is unchanged . There is no evidence for pulmonary edema . Pleural effusion is unlikely .
    OUTPUT:
    
Intra aortic balloon pump 2 .1 cm below the aortic knob . No significant change since ___ .