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clinicaltrials.gov Identifier: NCT00371891.

T he use of the left internal mammary artery (LIMA) during coronary artery bypass graft (CABG) surgery has become the gold standard for revascularization. However, stenosis within the proximal left subclavian artery may cause reduction, and even reversal, of flow within the LIMA and the vertebral artery ( Figure 1). The physiology of this phenomenon parallels subclavian steal syndrome, and has been termed coronary-subclavian steal syndrome (CSSS). We report a case of complete proximal subclavian occlusion with cardiac and neurological manifestations that was treated with angioplasty and stenting. CASE PRESENTATIONA 61-year-old Guyanese man who immigrated to Canada in 1996 experienced crescendo angina and a myocardial infarction in 2000. Coronary angiography demonstrated triple-vessel disease, and the patient underwent CABG surgery; a LIMA to left anterior descending artery (LAD) graft, and saphenous vein grafts to the first obtuse marginal (OM) and the right coronary artery (RCA) were used. He was asymptomatic following surgery.Over the next five years, the patient noted a decreased exercise tolerance. Initially, he experienced a 'hot' feeling in his left upper chest progressing to left chest pressure on exertion, which radiated to the neck. He also complained of light headedness, left arm pain and numbness on exertion. He was able to walk one to two blocks (or one flight of stairs) before the onset of symptoms, which were relieved by rest.He did not associate any of his symptoms with the movement of his left arm. However, he noted reduced sensation in his left arm compared with the right. He denied shortness of breath, paroxysmal nocturnal dyspnea or orthopnea. He had no syncopal episodes.Coronary risk factors included type 2 diabetes mellitus, hypertension and hyperlipidemia. Medications included acetylsalicylic acid, atenolol, atorvastatin and metformin.On examination, his heart rate was 54 beats/min in the right arm, with a nonpalpable pulse in the left arm. The blood pressure in his right arm was 140/80 mmHg and 76/40 mmHg in his left arm. Otherwise, he had a normal physical examination.The patient underwent exercise testing with sestamibi perfusion imaging. He was able to exercise 4 min 12 s, at which time he developed chest pain and shortness of breath. He achieved a heart rate of 115 beats/min. An electrocardiogram showed ST depression to a maximum of 2.7 mm in the anterior leads, although imaging did not show perfusion defects.A multiacquisition gated scan revealed an ejection fraction of 62%. Echocardiography revealed normal left ventricular function, dimension and valves. A neck ultrasound with Doppler revealed less than 50% stenosis of the left internal carotid artery and retrograde blood flow in the left vertebral artery. Coronary angiography revealed retrograde flow up the LIMA, with distal subclavian filling (Figure 2). Angiography of the aorta revealed 100% stenosis at the left subclavian origin (Figure 3).The patient underwent left subclavian artery stenting. The left brachial artery was punctur...

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