Coronary Steal Syndrome Caused by an Unligated RIMA Branch: Successful Treatment With Vascular Embolization

Arterial conduits improve long-term outcomes in coronary bypass surgery, but persistent right internal mammary artery (RIMA) side branches can cause ischemia via coronary steal.

A 62-year-old man presented with recurrent chest pain and non-ST-elevation myocardial infarction 1 year after coronary artery bypass graft (CABG) with RIMA, left internal mammary artery, and saphenous vein grafts. Evaluation showed significant stenosis of a vein graft and a large unligated RIMA side branch suspected of coronary steal. The side branch was successfully embolized, resulting in symptom resolution.

Persistent RIMA side branches are a rare but important cause of recurrent ischemia after CABG. Literature suggests percutaneous embolization can effectively treat symptomatic cases. This case demonstrates the need for clinicians to consider coronary steal in post-CABG patients with unexplained angina.

Persistent RIMA side branches may cause ischemia post CABG and should be considered in patients with recurrent angina.