Scintigraphic assessment of arterial embolism at mixed thrombin and technetium 99m injection therapy for femoral pseudoaneurysms.

BACKGROUND: Clinically evident arterial thrombosis is rare following thrombin injection therapy for femoral pseudoaneurysm. However, it is unclear to what extent injected thrombin may pass to the ipsilateral lower limb arteries. AIMS: To assess if technetium 99m injected at the time of thrombin injection for femoral artery pseudoaneurysm therapy passes into the adjacent lower limb arteries.
METHODS: This was a prospective trial with institutional review board approval. Four consecutive patients with common femoral pseudoaneurysms and failed manual compression were enrolled. Under real-time colour flow doppler ultrasound, a mixture of 1000 IU thrombin and approximately 200 MBq technetium 99m was injected in 0.1-mL doses into the pseudoaneurysm until thrombosis occurred. Gamma camera imaging of the syringe before injection, the injected groin after thrombosis and the syringe after injection were performed. Analysis of the gamma camera information was performed to determine the amount of technetium 99m deposited in the arterial tree.
RESULTS: All the procedures were technically successful. A mean of 33% (range 3-50%; SD 21) of the administered technetium 99m dose was deposited in the arterial circulation during pseudoaneurysm therapy. No clinically evident arterial thrombosis was identified.
CONCLUSION: Technetium 99m is routinely deposited in the arterial circulation following injection of a mixture of thrombin and technetium for therapy of common femoral artery pseudoaneurysms. This suggests that arterial passage of thrombin is more common than clinically evident.