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Left subclavian artery coverage during thoracic aortic stent grafting associated with low incidence of arm complications, type II endoleaks, study data indicate

Thursday, December 18 2008 | Comments

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What's This? Coverage of the left subclavian artery (LSA) during thoracic aortic stent grafting is associated with a low incidence of arm complications and type II endoleaks, and when endoleaks do occur they may be effectively treated using retrograde coil embolization of the LSA origin via the ipsilateral brachial artery, according to data from a recent study.

To determine the sequelae associated with covering the LSA during thoracic aortic stent grafting, researchers reviewed prospectively gathered data from all 289 investigational device exemption-approved patients who underwent thoracic aortic stent grafting at the Arizona Heart Institute from 2000 to 2006. Patients were evaluated with contrast-enhanced computed tomography (CT) scanning on the first postoperative day and during follow-up at 1, 6, and 12 months. Outcomes from patients who received endoluminal grafts to the distal aortic arch and the descending thoracic aorta, necessitating coverage of the LSA (LSA covered group; n=66), were compared with those from patients who received endoluminal grafting isolated to the descending thoracic aorta (conventional group; n=223).

Overall, the majority of patients in both groups received a Gore TAG endoprosthesis (W.L. Gore & Associates Inc.), though a subset of patients received Medtronic Talent devices (Medtronic Inc.). Postoperative outcome variables were similar between groups, except patients in the LSA covered group had a significantly higher incidence of left upper extremity claudication relative to the conventional group (7.6% vs 0.5%; P=.003). The incidence of neurologic complications was also similar.

Twelve patients (18%) from the LSA covered group developed a type I (n=6) and/or II (n=7) endoleak diagnosed immediately after stent grafting or during follow-up. Retrograde flow from a covered LSA accounted for 5 of the type II endoleaks, while patent intercostals accounted for the remaining 2.

Type II endoleaks associated with LSA coverage were successfully treated with either retrograde coil embolization from the left brachial artery (n=3) or left subclavian ligation in conjunction with carotid-subclavian bypass (n=1).

"Retrograde coil embolization of the LSA origin via the ipsilateral brachial artery is a simple and effective method to treat type II endoleaks," the authors noted.

Further, 2 patients with type II endoleaks emanating from patent intercostals were managed conservatively, whereby 1 patient's endoleak resolved by 6 months and the other patient was lost to follow-up, and the remaining patient with a small type II endoleak from a patent LSA demonstrated complete resolution at the 6-month CT scan.

The 30-day mortality rates were similar between groups (6.1% for LSA covered and 4.5% for conventional), as were 5-year mortality rates (68.3% and 69.4%, respectively).

"In the majority of patients requiring endovascular repair for a broad range of thoracic aortic pathologies, coverage of the LSA without previous or concomitant revascularization is well-tolerated, provided they have no contraindication to unprotected left subclavian overstenting," the authors of the study concluded. "Because the risk of critical left upper extremity ischemia is negligible, postoperative left subclavian revascularization can be performed electively for the small percentage of patients in whom persistent and intolerable arm claudication or vertebrobasilar insufficiency develops." (Peterson MD, et al. J Thorac Cardiovasc Surg 2008;136:1193-1199.)

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