How do you get pseudoaneurysm?

What Causes a Pseudoaneurysm?

A pseudoaneurysm, sometimes referred to as a "false aneurysm," isn’t quite the same as a true aneurysm—but it’s still a serious condition. Instead of a weakened blood vessel wall bulging outward (as with a true aneurysm), a pseudoaneurysm happens when the wall is injured, allowing blood to leak out and pool in the surrounding tissue. This collection of blood forms what looks like a sac, held together not by vessel layers but by the body’s surrounding tissue, which acts as a temporary barrier.

How does this happen? The most common cause is trauma—often from medical procedures. For example, after a cardiac catheterization or other invasive test where a catheter is inserted into an artery (usually in the groin), a small tear can develop at the puncture site. If the vessel doesn’t seal properly, blood may leak and form a pseudoaneurysm. Other causes include blunt trauma (like from an accident), infections, or even complications from surgery.

Most of the time, a pseudoaneurysm develops in arteries, particularly the femoral artery, but it can occur elsewhere. Symptoms might include pain, swelling, or a pulsating lump near the injury site. Some go unnoticed until detected during an ultrasound or other imaging test.

While some small pseudoaneurysms may resolve on their own, larger ones can pose risks—like continued bleeding, clot formation, or even rupture. Treatment depends on size and symptoms, and can range from ultrasound-guided compression to minimally invasive procedures or surgery.

Early detection is key. If you've had a recent procedure involving blood vessels and notice unusual swelling or pain, it's worth getting it checked. Awareness and timely care can prevent complications.