A pseudoaneurysm, or pseudoaneurysm of the vessels, occurs when a blood vessel wall is injured and the leaking blood collects in the surrounding tissue. It is sometimes called a false aneurysm. In a true aneurysm, the artery or vessel weakens and bulges, sometimes forming a blood-filled sac.

A pseudoaneurysm may be a complication of cardiac catheterization, a procedure in which a thin, flexible tube (catheter) is inserted into a groin artery (femoral artery) and threaded through blood vessels up to your heart. Cardiac catheterization is generally used to diagnose and treat heart disease. A pseudoaneurysm can result from this procedure if blood leaks and gathers outside the artery where the catheter was inserted.

Pseudoaneurysms can also occur in other arteries throughout the body as a result of:

• Infection
• Rupture of an aneurysm
• Surgery
• Trauma

A small pseudoaneurysm of a femoral artery due to cardiac catheterization may go undetected and not cause any complications. You may not notice it until days or weeks after the procedure. Your doctor may recommend a watchful-waiting approach and an occasional duplex ultrasound test to see if it goes away on its own.

If the pseudoaneurysm is wider than 2 centimeters, or if you take certain medications such as blood thinners, your doctor will likely recommend one of these treatments:

• Ultrasound-guided compression repair. In this treatment, your doctor will look for your pseudoaneurysm using ultrasound imaging. Once the pseudoaneurysm is found, your doctor presses on it to release the built-up blood.
• Ultrasound-guided medication. In this treatment, your doctor uses ultrasound imaging to locate and inject a blood clot-forming medication (thrombin) into the pseudoaneurysm. The medication causes the pooled blood to clot.
• Surgery. If your doctor doesn't think either ultrasound-guided treatment will work, he or she may recommend surgery to correct it.