Coronary-subclavian steal syndrome: a case report of a rare entity that can become a deadly threat.

Background: In patients who underwent coronary artery bypass graft (CABG), the coronary-subclavian steal syndrome (CSSS) is characterized by a subclavian artery stenosis proximal to the origin of the internal mammary artery resulting in functional graft failure.

Case Summary: A 62-year-old gentleman underwent CABG following a non-ST elevation myocardial infarction and an angiogram showing left main stem and three-vessel disease. Forty-eight hours later he developed cardiogenic shock that improved with inotropic support and intra-aortic balloon pump insertion. However, 7 days later, he deteriorated again and even though the myocardial injury markers and echocardiogram were normal, an angiography was performed showing significant CSSS. Due to the chronic nature of his subclavian stenosis and the severity of the cardiogenic shock, the heart team decided to treated his epicardial disease percutaneously and occlude the left internal mammary artery in its mid-segment with coils. The patient was discharged home 28 days after CABG and has remained since asymptomatic with improvement in his functional class.

Discussion: Coronary-subclavian steal syndrome is a rare but fatal complication with increased morbidity and mortality due to reduced awareness amongst medical professionals. Subclavian artery stenosis stenting is the gold standard treatment; herein we present a new approach for complex and very sick patients in whom it is not possible to open the subclavian artery percutaneously. Increased awareness and prompt diagnosis of this pathology in CABG patients are essential for successful outcomes.