The appearance of the inferior vena cava in imaging studies can help to identify a patient with right ventricular overload.

Features of a distended inferior vena cava in right ventricular overload:

(1) maximum diameter > 2.1 cm

(2) percent collapsibility < 50% (inferior vena cava collapse index)


The maximum diameter of the IVC is at the end of expiration.

The minimum is during inspiration.


percent collapse =

= ((maximum diameter) - (minimum diameter)) / (maximum diameter) * 100%


NOTE: The inferior vena cava collapse index can help in identifying a patient with hypovolemia.

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