A case of coronary subclavian steal syndrome treated with carotid-subclavian bypass

SESSION TITLE: Interventions in Cardiopulmonary Diseases SESSION TYPE: Rapid Fire Case Reports PRESENTED ON: 10/09/2023 02:10 pm - 02:55 pm INTRODUCTION: Coronary subclavian steal syndrome (CSSS) is a rare cause of acute myocardial ischemia following coronary artery bypass graft surgery (CABG) when the left internal mammary artery (LIMA) is used to bypass the left anterior descending artery (LAD) in a patient with co-existent stenosis of the left subclavian artery prior to the origin of the LIMA to LAD graft [1]. CSSS results from diversion of blood flow from the myocardium and retrograde blood flow through the LIMA to supply the subclavian artery distal to the stenosis. CASE PRESENTATION: A 62-year-old female presented with new onset chest pain for two days. The patient had a history of triple CABG (LIMA to LAD, reverse saphenous vein graft to left posterolateral artery, and reverse saphenous vein graft to first diagonal artery) two weeks prior to admission. Additional medical history included hypertension, hyperlipidemia, peripheral artery disease and tobacco use. Electrocardiogram showed Q-waves in the anterolateral leads. Initial troponin was elevated at 1.33 ng/mL. Intravenous heparin was initiated for non-ST-segment elevation myocardial infarction (NSTEMI). Transthoracic echocardiogram revealed a reduced left ventricular ejection fraction of 35% with dyskinesis of the apical myocardium. Coronary angiography revealed a proximal total occlusion of the left subclavian artery with retrograde flow from LAD to LIMA to supply the distal left subclavian artery (Figure 1), establishing the diagnosis of CSSS. Due to the long segment of subclavian chronic total occlusion (CTO) and risk of jailing off the vertebral artery, vascular surgery proceeded with a left carotid to subclavian artery bypass using an 8-mm Dacron graft without complications. Postoperative course was uneventful resulting in resolution of chest pain and the patient was discharged 5 days following the operation. DISCUSSION: CSSS is an underestimated cause of angina despite an increasing number of reported cases following CABG [1]. In comparison to saphenous vein grafts, the LIMA has shown to have a superior patency rate and survival benefit thus making it the preferred conduit for CABG of the LAD [2]. However, stenosis of the left subclavian artery proximal to the IMA ostium can lead to impaired coronary artery flow. Previously reported cases of CSSS resulted from chronic progression with development of subclavian artery collateral circulation and most patients were asymptomatic [2]. Our case is unique as evident from the acute presentation of NSTEMI and new-onset heart failure from CSSS two weeks following CABG. Revascularization is the definitive treatment for CSSS in addition to medical therapies directed at controlling risk factors. Endovascular intervention has demonstrated long term efficacy and decreased morbidity and mortality [3]. Surgical revascularization such as carotid-subclavian bypass is considered for failed endovascular therapy or when anatomy is deemed unsuitable as evident in our case for which there was a high risk of jailing off the vertebral artery [1]. CONCLUSIONS: Our case highlights CSSS following CABG as a rare cause of ischemic cardiomyopathy. Treatment modality depends on anatomic variation, with consideration of the proximity to the ipsilateral vertebral artery. Endovascular intervention or surgical revascularization is essential in order to restore coronary artery perfusion. REFERENCE #1: Lak HM, Shah R, Verma BR, Roselli E, Caputo F, Xu B. Coronary Subclavian Steal Syndrome: A Contemporary Review. Cardiology. 2020;145(9):601-607. doi:10.1159/000508652 REFERENCE #2: De Roeck F, Tijskens M, Segers VFM. Coronary-subclavian steal syndrome, an easily overlooked entity in interventional cardiology. Catheter Cardiovasc Interv. 2020;96(3):614-619. doi:10.1002/ccd.28362 REFERENCE #3: Cua B, Mamdani N, Halpin D, Jhamnani S, Jayasuriya S, Mena-Hurtado C. Review of coronary subclavian steal syndrome. J Cardiol. 2017;70(5):432-437. doi:10.1016/j.jjcc.2017.02.012 DISCLOSURES: No relevant relationships by Haris Ahmed No relevant relationships by JONATHAN BROWN No relevant relationships by Hassan Kamran No disclosure on file for Syed Raza No relevant relationships by Jordan Torres No disclosure on file for Xianfeng Wen