After catheterization in a cardiac patient, what is a probable cause for a pulsatile mass in the groin?

The presence of a pulsatile mass in the groin following catheterization in a cardiac patient is most likely indicative of a pseudoaneurysm of the femoral artery. This condition arises when there is a break in the arterial wall (often due to trauma from the catheterization), causing blood to escape into the surrounding tissue but still remain contained within a wall of tissue, which results in a pulsatile mass.

Pseudoaneurysms can occur at the site of vascular access, particularly in the femoral artery, due to complications such as improper technique, high puncture, or anticoagulation during procedures. The distinguishing characteristic of a pseudoaneurysm is the pulsation, which correlates with the heartbeat, and this pulsatile nature differentiates it from other possible complications.

In contrast, while a hematoma can also form after catheterization, it typically presents as a non-pulsatile swell or bruise rather than a pulsatile mass, as it is the result of blood accumulation without the arterial wall structure containing the blood. Venous thrombosis presents with swelling and pain rather than a pulsatile mass, and infection at the catheter site may manifest with redness, warmth, and possibly drainage but does not create a pulsatile mass. Thus,