A 67-year-old female with a history of dyslipidemia, hypertension, coronary artery disease status post coronary artery bypass graft (CABG) surgery presents for evaluation of progressive left upper extremity claudication symptoms described as exercise-induced left arm pain, left middle finger tingling, and left arm fatigue. There are no symptoms at rest. CABG includes left internal mammary artery (IMA) to left anterior descending (LAD) artery grafting. Physical exam is notable for a left upper extremity blood pressure of 90/60 mm Hg and right upper extremity blood pressure of 136/66 mm Hg; normal jugular venous pressure, normal S1 and S2 without murmurs; and 2+ right radial pulse, 1+ left radial pulse, 2+ right femoral pulse, 2+ left femoral pulse. Vascular Doppler shows left subclavian artery occlusion (Figure 1) with retrograde flow in the left vertebral artery (Figure 2), and computed tomography scan shows proximal left subclavian artery occlusion with distal left subclavian artery perfusion via retrograde flow from the left vertebral artery (Figure 3). The patient undergoes angiography via the right femoral artery and right radial artery (Figure 4) for further delineation of anatomy and consideration of treatment options.
Figure 1: Vascular Ultrasound Color Doppler Evidence of Subclavian Occlusion
Figure 2: Vascular Ultrasound Doppler Evidence of Retrograde Flow in Vertebral Artery
Figure 3: CT Angiogram Evidence of Proximal Subclavian Artery Occlusion
Figure 4: Long Segment Proximal Subclavian Occlusion via Invasive Angiography
Which of the following is the next best treatment option in this patient with symptomatic left subclavian steal syndrome?
The correct answer is: C. Carotid-subclavian bypass surgery plus optimal medical management.
The patient is symptomatic despite optimal medical therapy; therefore, further revascularization treatment options should be entertained. Although endovascular revascularization of the chronic total occlusion may be attempted, the anatomy is unfavorable given the following: 1) long segment proximal left subclavian artery occlusion, and 2) the left vertebral artery is situated within 5 mm of the distal aspect of the subclavian artery occlusion. The next best treatment option for this patient is surgical revascularization, which is usually performed via common carotid to subclavian artery bypass surgery. In brief, subclavian steal syndrome occurs when a significant stenosis compromises distal perfusion to the IMA, vertebral artery, or axillary artery. Atherosclerosis is the most common cause of subclavian stenosis; however, large artery vasculitis, thoracic outlet syndrome, and stenosis after surgical repair of aortic coarctation or tetralogy of Fallot are other possible causes. Arm claudication associated with coolness or paresthesias of the extremity is the most common complaint in symptomatic patients such as this case. Unilateral reversal of vertebral flow may cause vertebrobasilar transient ischemic attacks (TIA) in a minority of patients with insufficient cerebral collateral flow especially when performing upper extremity exercises. These episodes would present classically as "drop attacks." Finally, a coronary-subclavian steal phenomenon manifest by angina may occur in patients who have undergone CABG if stenosis occurs in the subclavian artery proximal to the take-off of an IMA graft utilized to perfuse a coronary artery. Common physical exam findings may include bilateral blood pressure and radial-femoral artery pulse discrepancies. In patients who have central nervous system symptoms, carotid stenoses should be addressed prior to an attempt at revascularization of the subclavian system. For patients with mild symptoms, medical therapy and observation may be appropriate as improvement without intervention has been described. In patients with burdensome symptoms, angioplasty and stenting can be performed when percutaneous intervention is unlikely to compromise the vertebral circulation.1-3 Technical success of the percutaneous approach can be achieved in >90% with five-year patency rates of 85%.4 Longer or more distal occlusions may be better addressed with surgical revascularization consisting of carotid-subclavian bypass, carotid transposition, or axillo-axillary bypass with patency rates in excess of 70% at five years.5
Burihan E, Soma F, Iared W. Angioplasty versus stenting for subclavian artery stenosis. Cocharne Database Syst Rev 2011;10:CD008461
Chatterjee S, Nerella N, Chakravarty S, Shani J. Angioplasty alone versus angioplasty and stenting for subclavian artery stenosis – a systematic review and meta-analysis. Am J Ther 2013;20:520-3.
Song L, Zhang J, Li J, et al Endovascular stenting vs. extrathoracic surgical bypass for symptomatic subclavian steal syndrome. J Endovasc Ther 2012;19:44-51.
Wang KQ, Wang ZG, Yang BZ, et al. Long-term results of endovascular therapy for proximal subclavian arterial obstructive lesions. Chin Med J (Engl) 2010;123:45-50.
Salam TA, Lumsden AB, Smith RB 3rd. Subclavian artery revascularization: a decade of experience with extrathoracic bypass procedures. J Surg Res 1994;56:387-92.