Where must an IVC filter be placed in relation to the renal veins?

• A. Superior
• B. Inferior
• C. At the level of
• D. Adjacent to

Answer: (B)

An IVC (Inferior vena cava) filter must be positioned inferior to the renal veins to ensure that it effectively captures emboli without obstructing blood flow from the kidneys. The renal veins drain blood from the kidneys into the IVC, and placing the filter below them allows it to intercept clots originating from the lower extremities and preventing them from traveling to the lungs, while still ensuring that the renal venous outflow remains unobstructed.

Positioning the filter superior to or at the level of the renal veins could risk blocking these vital vessels, potentially leading to complications such as renal vein thrombosis. Hence, the optimal placement is definitively inferior to the renal veins to maintain renal function and to perform its role in preventing pulmonary embolism effectively.