In the management of a pseudoaneurysm, thrombin may be injected under guidance to promote thrombosis.

• A. True
• B. False
• C. Only during surgery
• D. Not used

Answer: (A)

Thrombin injection under imaging guidance is a well-established, minimally invasive way to treat a pseudoaneurysm. Injecting thrombin directly into the pseudoaneurysm sac induces rapid clot formation, filling the sac and sealing off the communication with the parent artery. This causes immediate thrombosis of the pseudoaneurysm and eliminates ongoing blood flow into the sac.

In practice, ultrasound guidance is used to place a fine needle into the sac, and a small amount of thrombin (often a small volume of a 1000 U/mL preparation) is injected while Doppler monitors the flow. The aim is immediate cessation of flow into the sac; if needed, additional small injections can be given until thrombosis is complete. This approach is a percutaneous, non-surgical option commonly used after arterial puncture procedures, offering a quick, high-success alternative to surgery—when the neck is accessible and there isn’t an contraindication.

Risks include the possibility that thrombin enters the parent vessel and causes distal embolization, so careful technique and imaging are essential. But when performed appropriately, it effectively promotes thrombosis and resolves the pseudoaneurysm, making the statement true.