Don't Ignore That Chest Pain: Positionally Dependent Coronary Subclavian Steal Syndrome.

Coronary subclavian steal syndrome (CSSS) is a complication incurred after coronary artery bypass grafting (CABG), characterized by retrograde blood flow through the left internal mammary artery (LIMA) graft to the left subclavian artery (SCA) distal to a SCA stenosis, thereby compromising myocardial perfusion from the LIMA despite its patency. We present a 40-year-old female with a history of triple-vessel CABG who presented with crescendo angina, notably when elevating her arms above her head. Atypical angina related to arm activity following successful LIMA bypass should prompt angiography directed to the left SCA, as well as to the LIMA graft. Typically, cases of CSSS are claudication dependent and not positionally related. This suggests a two-pronged pathophysiological mechanism of both demand ischemia and mechanical obstruction, which is not well described in previous literature.