A 59-year-old female patient with multiple cardiovascular risk factors (type II diabetes, hypertension, hypercholesterolemia, smoker) had suffered an anterior myocardial infarction (AMI) 5 years ago and later developed a CCS class II angina pectoris. Catheterization disclosed an occluded mid-segment in the left anterior descending artery (LAD) and an 80% lesion in the circumflex artery (Cx). A coronary artery bypass graft (CABG) was then performed with a left internal mammary anastomosis (LIMA) to LAD and a radial free graft, from LIMA to an obtuse marginal (OM) branch. The patient remained asymptomatic until recently, in spite of the severe risk factors. Three months later, moderate angina reappeared as well as episodes of dizziness, mainly during upper limb exercise. One month later, a new AMI in the lateral wall occurred. An urgent femoral catheterization revealed thrombotic occlusion of the Cx artery. The LAD artery had an old occlusion and the LIMA graft could not be catheterized. The right coronary artery (RCA) was normal. Primary angioplasty of the culprit Cx was performed and a bare metal coronary stent was successfully deployed. Rest chest pain was resolved, but mild effort angina and dyspnea resumed one week later. A physical examination disclosed absent pulses in the left arm. A cardiac CT Angiography (CTA) was then performed.
A total occlusion of the left subclavian artery was demonstrated, 1.8 cm from its origin, proximal to the LIMA and ipsilateral vertebral artery. Both of these supply a scant axillary artery flow (Fig. 1). In spite of this fact, the LIMA was well enhanced, with a good anastomosis to the mid LAD (Figs. 1 A, C and Fig. 2). The radial (LIMA to OM) anastomosis was totally occluded, only a metal clip path could be seen (Fig. 1C). The Cx stent was patent, with no signs of restenosis and the RCA was normal (Figs. 1 and 2). The right brachiocephalic and left carotid arteries were also normal (Fig. 1). The left ventricular ejection fraction was 53%, with lateral wall and apical akinesis (Fig. 3). The left atrium was enlarged (Figs. 1B and 3A). A complementary triplex Doppler scan disclosed reversal of the left vertebral artery flow. A diagnosis of coronaryvertebral subclavian steal syndrome was confirmed.
Coronary and/or vertebral subclavian steal syndrome is a well-known late complication of CABG, occurring in patients with pre-existent mild to moderate subclavian atherosclerotic disease. It is unclear whether the surgical procedure itself accelerates the growth of the lesions in the subclavian artery. This is mainly due to the enhanced local flow and consequent endothelial shear stress. In the patient described, pre-operative upper limb arterial pressures were symmetrical and poor risk factors might also have contributed to the subclavian disease progression. In this well-documented case, a large acquisition window, ranging from the middle neck region to the diaphragm, was used to ensure good anatomical coverage; primarily that of the proximal supra-aortic vessels to prepare for a future surgical decision. Since the left carotid artery is disease free, a left carotid-axillary shunt is being proposed. Siemens SOMATOM Perspective with iTRIM technique allowed for fast cardiac CTA acquisition with a higher temporal resolution. Together with the fast volume rendering technique (VRT) on syngo.via, superb anatomic details could be yielded to avoid further invasive studies.