After femoral artery catheterization, which finding favors a femoral artery pseudoaneurysm over an arteriovenous fistula?

• A. Continuous bruit with no palpable mass
• B. Pulsatile mass with systolic bruit and diastolic pressure equalization
• C. No mass associated, continuous bruit
• D. Decreased distal perfusion without bruit

Answer: (B)

Main concept: After femoral artery access, the way the abnormal connection presents helps distinguish a pseudoaneurysm from an arteriovenous fistula. A pseudoaneurysm arises when arterial wall injury leaks blood into a contained hematoma that remains in communication with the artery, producing a pulsatile mass next to the puncture site and a systolic bruit. An arteriovenous fistula is a direct artery-to-vein connection that creates a continuous bruit and a thrill, with high-flow shunting that can lower distal arterial pressures.

Why this finding is the best: A pulsatile mass adjacent to the access site with a systolic bruit is classic for a pseudoaneurysm. The mass reflects the held-open arterial leak forming a sac that expands with each heartbeat; the systolic bruit comes from rapid blood entry into that sac during systole. The diastolic pressure equalization mentioned here can be seen in this context as part of the abnormal flow dynamics near the arterial rupture, but the discrete pulsatile mass is the most specific clue pointing to a contained arterial leak rather than a direct AV connection.

Brief contrast: If the exam described no discrete mass but a continuous bruit with a thrill, that would favor an AV fistula. If there were a diminished distal perfusion without any bruit or a nonpulsatile mass, other vascular problems would be more likely.

So the combination of a pulsatile mass and systolic bruit aligns with a femoral artery pseudoaneurysm following catheterization.