Persistent Angina After Successful LAD Stenting: Coronary-Subclavian Steal Syndrome as the Hidden Culprit

Abstract

Introduction. Coronary-subclavian steal syndrome (CSSS) is an uncommon but clinically important cause of myocardial ischemia in patients with a left internal mammary artery (LIMA) coronary bypass graft. Proximal left subclavian artery stenosis or occlusion may reverse flow through the LIMA graft, causing recurrent angina despite apparently successful coronary revascularization. This report aims to highlight CSSS as an overlooked cause of persistent angina after percutaneous coronary intervention (PCI) and demonstrate successful endovascular treatment of chronic left subclavian artery occlusion.

Methods. We report an 82-year-old man with coronary artery disease (CAD), previous coronary artery bypass grafting (CABG ×4) including a LIMA–LAD graft, diabetes, hypertension, and a permanent pacemaker, presenting with exertional angina. Initial angiography demonstrated significant native LAD disease and complete proximal left subclavian artery occlusion. The symptoms were initially attributed to coronary disease, and two stents were implanted in the native LAD. Three months after successful PCI, the patient reported persistent angina and dizziness, particularly during left-arm exertion, associated with arm claudication. A 35-mmHg inter-arm systolic blood pressure difference raised suspicion of CSSS. Repeat angiography demonstrated patent LAD stents and retrograde flow through the LIMA graft, confirming the diagnosis. The chronic left subclavian occlusion was recanalized using a combined femoral antegrade and radial retrograde approach, followed by balloon-expandable stent implantation.

Results. Technical success was achieved without complications, restoring antegrade subclavian and LIMA flow and equalizing arm pressures. Angina, dizziness, and arm claudication completely resolved. At 6-month follow-up, the patient remained asymptomatic with no evidence of restenosis.

Discussion. CSSS should be considered in patients with a LIMA graft and persistent angina despite successful PCI, particularly when symptoms are triggered by left-arm exertion. Routine bilateral blood pressure measurement may provide a simple diagnostic clue, facilitate timely subclavian revascularization, and prevent unnecessary coronary reinterventions.