Subclavian Artery Pseudoaneurysm: Successful Exclusion with a Covered Self-Expanding Stent<br />
CATHETER TECHNIQUES FOR THE TREATME

Pseudoaneurysms are encapsulated hematomas that communicate with an artery because of an incomplete seal by the media. Although femoral artery pseudo-aneurysms occurring as a complication of cardiac catheterization are familiar to an interventionist, a subclavian pseudoaneurysm is a rare clinical entity. Due to their non-compressibility, relative proximity to vital intra-thoracic structures and the unpredictable risk of rupture, they pose unique challenges in management. In this report, the superiority of a covered, self-expanding stent over a conventional stent in the minimally invasive management of subclavian artery pseudoaneurysms is illustrated. Case Report.A 69-year-old female with symptomatic aortic stenosis was electively admitted for valve replacement. Her past medical history was significant for coronary artery disease. A coronary artery bypass procedure using a left internal mammary artery was performed several years earlier. Her other medical problems included essential hypertension and chronic obstructive pulmonary disease. In the pre-operative care unit, a triple lumen catheter was inserted via the left subclavian vein for intravenous access and fluid management. The anesthesiologist reported difficulty in introducing this line. The valve surgery itself was uneventful, but on the first post-operative day, a large pulsatile mass was noted in the left supraclavicular region. By the fifth post-operative day, the patient was complaining of left arm weakness and parasthesias. Doppler studies confirmed the clinical suspicion of a pseudoaneurysm of the subclavian artery. Angiography identified the pseudoaneurysm location to be distal to the origin of the left internal mammary artery and the vertebral artery. The pseudoaneurysm was initially treated in the interventional radiology suite with a conventional self-expanding Wall Stent (Boston Scientific/Scimed, Inc., Maple Grove, Minnesota) without success. The following day, a covered, self-expanding Wall Stent was used to seal the leaking pseudoaneurysm. A neurological evaluation with nerve conduction studies and electromyography demonstrated a severe left upper and moderate lower brachial plexopathy. Arrangements were then made for outpatient neuro-rehabilitation and the patient continues to make good progress. Discussion. The incidence of arterial pseudoaneurysms ranges from 0.4–1.0%.1 They are most commonly the result of inadvertent arterial injury during subclavian vein cannulation. Blunt trauma is a less common etiology. Until recently, the only available treatment for subclavian artery pseudoaneurysms was surgery. This usually involved either resection or exclusion of the aneurysm with direct reconstruction of the vessel or extra-anatomic bypass.2–5 This procedure was complicated, frequently requiring a sternotomy because of the intra-thoracic course of the subclavian artery. More recently, less invasive methods for exclusion of pseudoaneurysms have been developed. The first reported case of endovascular repair of a subclavian artery was an effort to prevent exsanguinating hemorrhage from an iatrogenic subclavian artery perforation.6 This approach is now being utilized to exclude pseudoaneurysm and treat perforations in other vascular beds. The experience in subclavian arteries remains limited because of the relatively infrequent occurrence.7 Using covered stents in the setting of subclavian artery pseudoaneurysms is not only safe, but provides a feasible alternative to seal leaking pseudoaneurysms, thus preventing major thoracic surgery.

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