LIMA-LAD Steal Syndrome as a Cause of Post-CABG Angina

Coronary steal from unligated side branches of the left internal mammary artery (LIMA) after coronary artery bypass grafting may lead to recurrent angina. A 64-year-old man presented with recurrent angina 2 years after coronary artery bypass grafting. Imaging showed perfusion defects in the territory of the left anterior descending artery (LAD). Coronary angiography revealed a large patent LIMA side branch. A percutaneous vascular plug successfully occluded the side branch, with symptom resolution. There is conflicting evidence regarding the diagnosis and treatment of coronary steal syndrome from LIMA graft. Despite the lack of formal guidelines, reversible anterior wall defects on stress testing may help identify patients with clinically significant symptoms. The side branches of the LIMA when unligated represent a relatively common anatomical variation that could have clinical implications. Large, unligated side branches when accompanied by anterior wall ischemia may indicate a diagnosis of LIMA-LAD steal amenable to percutaneous intervention.