Abstract 10148: Prevalence, Clinical Characteristics and Cardiovascular Outcomes of Acute Coronary Syndrome Attributable to Coronary Subclavian Steal Syndrome in Patients with a History of Coronary Artery Bypass Grafting

Abstract

Introduction: Coronary subclavian steal syndrome (CSSS) is coronary steal phenomenon due to subclavian artery stenosis (SAS) in patients with a history of CABG using internal mammary artery (IMA). While CSSS could cause acute coronary syndrome (ACS), its frequency, clinical characteristics and cardiovascular outcomes remain unknown. Methods: The current study was a retrospective multi-center analysis of 142 ACS patients who previously received CABG from January 2007 to October 2020. CSSS was defined as myocardial ischemia due to SAS. Clinical characteristics and cardiovascular events (=cardiac-cause death + myocardial infarction + stroke) were compared in subjects with and without CSSS. Results: CSSS was identified in 7.0% (=10/142) of study subjects. Of these, 1, 6 and 3 CSSS cases had SAS at right, left and both subclavian arteries, respectively. The averaged pressure gradient at SAS site was 31±13mmHg. ACS subjects attributable to CSSS were more likely to exhibit NSTEMI (90% vs. 52%, p=0.02), a history of hemodialysis (40% vs. 14%, p=0.03) and peripheral artery disease (70% vs. 20%, p<0.001). Of note, all of 4 CSSS subjects receiving hemodialysis had their arterial-venous fistula at the same side of SAS. With regard to revascularization procedure in CSSS subjects, primary endovascular treatment for SAS was performed in only 2 cases. Furthermore, despite SAS as a culprit lesion of ACS, primary PCI for native coronary lesion was conducted in other 6 cases. As a consequence, most of them (=5/6) required additional revascularization of SAS after primary PCI due to unresolved myocardial ischemia or chest pain. During 50-month observational period, CSSS was associated with a greater likelihood of cardiovascular (p=0.003) and stroke events (p<0.001, Figure). Conclusions: A substantially elevated cardiovascular risk was observed in ACS patients attributable to CSSS. This finding suggests clinical needs to meticulously evaluate SAS before and after CABG using IMA.