Coronary subclavian steal syndrome causing acute coronary syndrome: a case report

Myocardial infarction on non-occluded coronary artery represents a very specific subset of acute coronary syndrome (ACS). Coronary subclavian steal syndrome (CSSS) is defined by a left subclavian artery stenosis in case of (i) left internal mammary artery (LIMA) used to bypass left anterior descending artery (LAD) and (ii) >75% stenosis of the left subclavian artery prior to the origin of the LIMA to LAD graft. Here we report the case of a CSSS causing ACS.

A 71-year-old man with history of LIMA to LAD coronary artery bypass surgery was admitted to the nephrology intensive care unit for acute kidney injury requiring dialysis. Due to rapid deterioration, altered left ventricular ejection fraction and elevated c-troponin levels, an urgent coronary angiography was performed. It revealed a subtotal occlusion of the left subclavian artery prior to the origin of the LIMA to LAD graft. This was responsible for a severely altered coronary flow in the LIMA and LAD. Revascularization of the proximal left subclavian artery with a stent was performed, enabling instant recovery of distal coronary flows.

ACS due to CSSS in this report highlights the complexity of the cardio–renal interaction. Patients with coronary artery bypass graft and chronic kidney disease commonly exhibit a higher risk for severe progression of atherosclerosis at multiple sites. CSSS treatments include secondary prevention measures and revascularization (if indicated) such as an endovascular approach.