Management of the Left Subclavian Artery during Endovascular Repair of the Thoracic Aorta

Endovascular repair is rapidly becoming the treatment of choice for thoracic aortic disease, which oftentimes involves or lies in close proximity to the left subclavian artery (LSA). In order to extend the proximal landing zone for the stent-graft and obtain an adequate seal, the LSA ostium is often covered, with or without concomitant subclavian artery revascularization. In this article, we review the LSA anatomy and consequences of LSA coverage as a backdrop for a discussion of the ramifications of LSA coverage during endovascular thoracic aortic repair (TEVAR). Early series reported high rates of LSA revascularization as an adjunct to endovascular repair for aortic pathology adjacent to the LSA ostium. Initial reports of low morbidity associated with simple LSA ostium coverage are not supported by contemporary literature, which suggests revascularization reduces the risks of cerebrovascular accident and spinal cord ischemia. Coverage of the LSA without revascularization may be justified only in emergency situations or when thorough investigations of cerebral and vertebrobasilar circulation have concluded that the risk to brain and spinal cord is low. Subclavian revascularization should be considered in the presence of a dominant left vertebral artery, bilateral carotid artery disease, an occluded/stenosed right vertebral artery, presence of a left internal mammary artery graft, or when a long length of thoracic aorta is covered.