Background: The risk of pseudoaneurysm (PSA) increases with the number of catheterizations performed for cardiovascular diagnosis and therapy. Thrombin injection, or “thrombinjection,” is an alternative to ultrasound-guided compression or surgical repair. Thrombinjection is effective and economical, but the specter of systemic arterial thrombosis hinders its wide application. We report cautionary steps taken prior to injection and lessons learned during our first 20 cases.

Methods and Results: Thrombinjection was performed under ultrasound (US) guidance in 12 women and 8 men with PSA after femoral catheterization. PSA varied in size from 17 to 39 mm with neck openings from 1.5 to 3.9 mm. Under local anesthesia and US longitudinal view, a 20-gauge US needle tip was placed in the PSA away from the neck. With 12 cases under 600 units, 100 to 2,300 units of thrombin (1,000 U/mL) were injected slowly. Slow injection, positioning of the ball of thrombus formed at the needle tip, probe compression, and combined or interchangeable use of US color flow and B-mode were the essential techniques utilized. All PSA thrombosed successfully on the first treatment. One patient had fever and another returned for compression treatment of a second, not recurrent, PSA.

Conclusions: Successful thrombinjection was accomplished by focusing on common femoral artery PSA with small neck openings, avoiding arteriovenous fistulas, and using standard thrombin concentration, US needle, state of the art ultrasonography, slow injection, thrombus ball positioning, and adjunctive probe compression.