Coverage of the left subclavian artery during thoracic endovascular aortic repair

Thoracic aortic stent grafts require proximal and distal landing zones of adequate length to effectively exclude thoracic aortic lesions. The origins of the left subclavian artery and other aortic arch branch vessels often impose limitations on the proximal landing zone, thereby disallowing endovascular repair of more proximal thoracic lesions.

Between October 2000 and November 2005, 112 patients received stent grafts to treat lesions involving the thoracic aorta. The proximal aspect of the stent graft partially or totally occluded the origin of at least one great vessel in 28 patients (25%). The proximal attachment site was in zone 0 in one patient (3.6%), zone 1 in three patients (10.7%), and zone 2 in 24 patients (85.7%). Patients with proximal implantation in zones 0 or 1 underwent debranching procedures of the supra-aortic vessels before stent graft repair. In one patient who underwent zone 1 deployment, the left subclavian artery was revascularized before stent graft deployment. Among patients who underwent zone 2 deployment with partial or complete occlusion of the left subclavian artery, none underwent prior revascularization. Patients were assessed postoperatively and at follow-up for development of neurologic symptoms as well as symptoms of left upper extremity claudication or ischemia.

Mean follow-up was 7.3 months. Among the 24 patients with zone 2 implantation, 10 (42%) had partial left subclavian artery coverage at the time of their primary procedure. A total of 19 patients experienced complete cessation of antegrade flow through the origin of the left subclavian artery without revascularization at the time of the initial endograft repair as a result of a secondary procedure or as a consequence of left subclavian artery thrombosis. Left upper extremity symptoms developed in three (15.8%) patients that did not warrant intervention, and rest pain developed in one (5.3%), which was treated with the deployment of a left subclavian artery stent. Two primary (type IA and type III) endoleaks (7.1%) and one secondary endoleak (type IA) (3.6%) were observed in patients who underwent zone 2 deployment. Three cerebrovascular accidents were observed. Thoracic aortic lesions were successfully excluded in all patients who underwent supra-aortic debranching procedures.

Intentional coverage of the origin of the left subclavian artery to obtain an adequate proximal landing zone during endovascular repair of thoracic aortic lesions is well tolerated and may be managed expectantly, with some exceptions.