Evaluation of coronary subclavian steal syndrome using sestamibi imaging and duplex scanning with observed vertebral subclavian steal

Coronary subclavian steal is defined as retrograde blood flow from the myocardium through the internal mammary artery graft, secondary to a proximal subclavian artery stenosis. The incidence of this syndrome in patients undergoing internal mammary artery grafts for coronary artery bypass is estimated to be 0.44%. Angiography remains the definitive diagnostic test for confirming this condition. We describe a noninvasive method for evaluating coronary subclavian steal syndrome in a 57-year-old man, with a 50-55% subclavian stenosis confirmed by angiography. Noninvasive evaluation using duplex scanning demonstrated normal vertebral artery blood flow. Technetium 99m-sestamibi (99mTc) imaging confirmed a fixed anterolateral defect. When left-arm isometric exercise was employed, retrograde vertebral artery blood flow was observed by Doppler imaging. A repeat 99mTc-sestamibi study documented an increase in tracer distribution in the anterolateral defect confirming reperfusion of the myocardium through the left internal mammary artery graft. The use of duplex scanning and 99mTc-sestamibi may serve as an adjunct in evaluating coronary subclavian steal syndrome as well as documenting transient vertebral subclavian steal in this patient population.