From the Guidelines
Thrombin injection is indicated for partially thrombosed pseudoaneurysms when the pseudoaneurysm has a narrow neck and adequate space exists between the pseudoaneurysm and the native artery to prevent inadvertent arterial thrombosis, as supported by the most recent guidelines 1.
Key Considerations
- The procedure involves ultrasound-guided injection of bovine or human thrombin directly into the pseudoaneurysm sac, avoiding the neck to prevent thrombin from entering the native circulation.
- Success rates exceed 90% with low complication rates, as demonstrated in studies such as 1, which reported a success rate of 93% with thrombin injection for catheter-related femoral pseudoaneurysms.
- Thrombin works by converting fibrinogen to fibrin, rapidly forming a stable clot within the pseudoaneurysm cavity.
- Patients should be monitored for allergic reactions to bovine thrombin and follow-up ultrasound is recommended to confirm complete thrombosis.
Indications and Contraindications
- Thrombin injection is typically considered after ultrasound-guided compression therapy has failed or is contraindicated, such as in patients who cannot tolerate compression due to pain, those on anticoagulation therapy, or when the pseudoaneurysm is in a location difficult to compress.
- The approach is particularly valuable for femoral artery pseudoaneurysms following catheterization procedures but may be used at other sites when anatomically suitable.
Guidelines and Recommendations
- The 2013 ACCF/AHA guideline recommendations 1 suggest that surgical repair is reasonable in patients with femoral artery pseudoaneurysms 2.0 cm in diameter or larger that persist or recur after ultrasound-guided compression or thrombin injection.
- Re-evaluation by ultrasound 1 month after the original injury can be useful in patients with asymptomatic femoral artery pseudoaneurysms smaller than 2.0 cm in diameter, as stated in 1 and 1.
From the Research
Indications for Thrombin Injection
Thrombin injection is indicated for the treatment of partially thrombosed pseudoaneurysms, particularly those that are iatrogenic in nature, such as postcatheterization femoral and brachial artery pseudoaneurysms 2, 3, 4, 5, 6. The procedure involves the percutaneous injection of thrombin into the pseudoaneurysm sac under ultrasound guidance.
Timing of Thrombin Injection
The optimal timing for thrombin injection is not strictly defined, but studies suggest that it is most successful when performed within the first two weeks after pseudoaneurysm diagnosis 2. However, thrombin injection can be effective even when performed later, and the decision to proceed with the procedure should be based on individual patient factors and the characteristics of the pseudoaneurysm.
Key Considerations
- Thrombin injection is a minimally invasive procedure that can be performed on an outpatient basis 5.
- The procedure is generally well-tolerated, with minimal discomfort and no significant complications reported in the majority of cases 2, 3, 4, 5, 6.
- The success rate of thrombin injection is high, with reported primary success rates ranging from 69.1% to 100% 2, 3, 4, 5, 6.
- Supplemental compression may be used to aid in the closure of partially thrombosed pseudoaneurysms, particularly in cases where thrombin injection is not initially successful 2.
Patient Selection
Patient selection for thrombin injection should be based on individual factors, including the size and location of the pseudoaneurysm, as well as the patient's overall health status and medical history. The presence of anticoagulation therapy does not appear to hinder the success of thrombin injection 5.