From the SIR Residents and Fellows Section (SIRRFS)
Teaching Topic: Outcomes of Ultrasound–Guided Thrombin Injection of Nongroin Arterial Pseudoaneurysms
Valesano JC, Schmitz JJ, Kurup AN, Schmit GD, Moynagh MR, Atwell TD, Lewis BD, Lee RA, Callstrom MR. J Vasc Interv Radiol. 2017 Jun 1. pii: S1051-0443(17)30477-3. doi: 10.1016/j.jvir.2017.05.003. [Epub ahead of print]
The authors describe their technique as follows:
1. Obtain baseline arterial duplex US imaging and Dopper waveforms of both the pseudoaneurysms and the origin artery proximal and distal to the site.
2. Evaluate pulses with ultrasound or palpation. Additionally, assess the relevant baseline sensorimotor function.
3. Using sterile technique and 1% lidocaine for anesthesia, advance a 20-25 gauge needle under ultrasound visualization until the tip of the needle is in the pseudoaneurysm sac.
4. Incrementally inject small aliquots of about 100 IU of 1000 IU/1 mL recombinant topical thrombin (The Medicines Company, Parsippany, New Jersey).
5. With intermittent Doppler imaging, monitor the pseudoaneurysm during injection until complete elimination of Doppler signal.
6. Reassess proximal and distal artery with US, pulses, and sensorimotor symptoms.
7. Follow-up imaging with duplex and Doppler US is recommended one day after the procedure.
What are the characteristics of pseudoaneurysms at higher risk of treatment failure?
It is difficult to draw conclusions from the small number of treatment failures from this series, however it appeared that the neck size was more predictive than the total size. The average size of pseudoaneurysms that remained successfully thrombosed at follow up were larger at 2.3cm +/- 1.6, while the average size for treatment failures were 2.0cm +/- 0.7. The neck diameter for treatment failures averaged 2.6 mm +/- 0.5 and 2.1 mm +/- 0.8 for treatment successes. Because of the small sample size, these results trended towards, but did not show statistical significance. Of the treatment failures, three were successfully treated with one retreatment, and the other two were successfully treated after two retreatments.
Questions to Consider
In the small previous reports, there have been two incidents of brachial artery thrombosis. In 2014, Garvin et al reported 14 cases of treatment with thrombin in the upper extremities.  In one of these cases, brachial artery thrombosis was identified by decreased Doppler amplitude distal to the pseudoaneurysm fifteen minutes after treatment. Emergent surgical revascularization was performed. Kang et al reported 5 upper extremity treatments in 2000.  In one case, the neck of the pseudoaneurysm persisted after initial thrombin injection, and after a small amount was injected into the residual neck, the patient began to experience symptoms of hand ischemia. Pulses returned and symptoms resided in less than ten minutes after treatment with 5000 IU of heparin.
What special considerations should be taken in patients on anticoagulation therapy?
Successful pseudoaneurysm treatment with thrombin in the setting of concurrent anticoagulation therapy has been well documented for femoral pseudoaneurysms in patients on heparin, warfarin, clopidogrel, and aspirin.  While the authors of this study did not report the anticoagulation status of the treated patients, in the previously mentioned study of 14 cases, 9 patients were on anticoagulants for atrial fibrillation. The efficacy in anticoagulated patients compared to ultrasound-guided compression remains one of the leading justifications for thrombin therapy.
1. Tisi PV, Callam MJ. Treatment for femoral pseudoaneurysms. Cochrane Database Syst Rev. 2013 Nov 29;(11):CD004981. doi: 10.1002/14651858.CD004981.pub4. Review. PMID: 24293322.
2. Garvin RP, Ryer EJ, Yoon HR, Kendrick JB, Neidrick TJ, Elmore JR, Franklin DP. Ultrasound-guided percutaneous thrombin injection of iatrogenic upper extremity pseudoaneurysms. J Vasc Surg. 2014 Jun;59(6):1664-9. doi: 10.1016/j.jvs.2014.01.009. Epub 2014 Feb 20. PMID: 24560862.
3. Kang SS, Labropoulos N, Mansour MA, Michelini M, Filliung D, Baubly MP, Baker WH. Expanded indications for ultrasound-guided thrombin injection of pseudoaneurysms. J Vasc Surg. 2000 Feb;31(2):289-98. PMID: 10664498.
4. Krueger K, Zaehringer M, Strohe D, Stuetzer H, Boecker J, Lackner K. Postcatheterization pseudoaneurysm: results of US-guided percutaneous thrombin injection in 240 patients. Radiology. 2005 Sep;236(3):1104-10. Epub 2005 Jul 29. PubMed PMID: 16055694.
Charles Hyman, MS4
Warren Alpert Medical School of Brown University