Vessel Update: Subclavian Access for Diagnosing and Treating Subclavian Disease

T he majority of the supra-aortic atherosclerotic occlusive lesions involves the left subclavian artery.1 Such disease results in a “subclavian steal,” which was first described in 1961 by Reivich et al.2 By occluding the left subclavian artery, arterial flow is provided by the right subclavian artery with flow into the right vertebral artery and then retrograde flow into the left vertebral artery, and subsequently into the left subclavian artery (Figure 1). A very common cause of stenotic lesions in these vessels, similar to other vessels, is athereosclerotic disease. However, other causes such as dissection, fibromuscular disease, and various vasculitidies are not infrequent.3 The diagnosis of subclavian steal is based on having upper-extremity ischemia in which a pressure gradient of 20 mm Hg is noted and symptoms of arm claudication, paresis, and atheroembolic digital ischemia are seen. Less commonly, there is vertebrobasilar insufficiency, which includes symptoms of ataxia, diplopia, syncope, vertigo, dizziness, nausea, and vomiting. Another syndrome, which has been increasing in frequency, includes coronary steal syndrome in which a stenosis proximal to internal mammary-coronary artery bypass may cause ischemic symptoms. The more frequent use of the left internal mammary artery (LIMA) for coronary bypass procedures has resulted in greater surveillance and treatment of the left subclavian artery. Although debatable, high-grade, proximal subclavian arterial stenoses in relatively asymptomatic patients is now considered appropriate therapy to maintain the capacity to use the LIMA. Many cases of subclavian artery stenosis or occlusive disease are discovered by CT angiography and MRA, in addition to traditional angiographic means (Figure 2). Innominate artery stenosis is relatively uncommon. When the atherosclerotic disease involves the innominate artery, the symptoms may be more severe and include cerebral symptoms. The occlusion in the innominate artery causes retrograde flow from the vertebral artery and into the right common carotid and the right subclavian artery. Symptoms generally include vertebrobasilar insufficiency with ataxia, diplopia, syncope, vertigo, dizziness, nausea and/or vomiting. It may also include upper-extremity ischemia and atheroembolic digital ischemia. Tools of the Subclavian Trade