Coronary Subclavian Steal Syndrome: An Unusual Cause of Angina in a Post-CABG Patient

Coronary subclavian steal syndrome is a rare complication of coronary artery bypass grafting surgery (CABG) when a left internal mammary artery (LIMA) graft is utilized. This syndrome is characterized by retrograde flow from the LIMA to the left subclavian artery (SA) when a proximal left SA stenosis is present. We describe a unique case of an elderly male who underwent CABG 6 years ago who presented with prolonged chest pain, mildly elevated troponins, and unequal pulses in his arms. A CTA of the chest demonstrated a severely calcified occluded proximal left SA jeopardizing his LIMA graft. Subclavian angiography was performed with an attempt to revascularize the patient's occluded left SA which was unsuccessful. We referred the patient for nuclear stress testing which demonstrated a moderate size area of anterior ischemia on imaging; the patient exercised to a fair exercise capacity of 7 METS with no chest pain and no ECG changes. Subsequent coronary angiography showed severe native three-vessel coronary artery disease with intermittent retrograde blood flow from the LIMA to the left SA distal to the occlusion, jeopardizing perfusion to the left anterior descending (LAD) coronary artery distribution. He declined further options for revascularization and was discharged with medical management.