Circulation. 2006;113:e930-e931
doi: 10.1161/CIRCULATIONAHA.105.571117
(Circulation. 2006;113:e930-e931.)
© 2006 American Heart Association, Inc.
Images in Cardiovascular Medicine |
Coronary-Subclavian Steal Syndrome Demonstrated by Cardiovascular Magnetic Resonance
Ping Chai, MRCP;
Mike Dubowitz, BSc, MBBS, MRCP, DPhil;
Raad Mohiaddin, FRCR, FRCP, FESC
From the Cardiovascular Magnetic Resonance Unit, Royal Brompton Hospital (P.C., R.M.), and Lister Hospital, East and North Hertfordshire NHS Trust (M.D.), London, UK.
Correspondence to Ping Chai, MRCP, Cardiovascular Magnetic Resonance Unit, Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK. E-mail Ping_CHAI{at}nuh.com.sg
Coronary-subclavian steal syndrome is a well-recognized complication after coronary artery bypass grafting using the internal mammary artery (IMA). It occurs when blood is diverted away from the coronary territory through the IMA to the upper limb as a result of significant stenosis in or occlusion of the proximal subclavian artery. We describe a case that was diagnosed using cardiovascular magnetic resonance (CMR).
A 56-year-old woman presented with a 10-year history of angina pectoris. For this condition she had undergone coronary angioplasty to her proximal left anterior descending coronary artery (LAD). Her angina recurred shortly after and repeat coronary angiography showed ostial LAD restenosis. She subsequently underwent coronary artery bypass grafting during which her left IMA (LIMA) was anastomosed to the LAD. After surgery, she was asymptomatic for &8 years before experiencing a recurrence of progressively worsening angina pectoris. Adenosine stress myocardial perfusion imaging showed a reversible defect in the anteroapical myocardium. Selective coronary angiography showed mild 20% stenosis in the left main stem and minor disease in the proximal LAD. Retrograde flow was present in the LIMA. The circumflex artery was patent and there was diffuse disease in the nondominant right coronary artery. On aortography, there was antegrade as well as retrograde flow in the LIMA, and the left subclavian artery was occluded at its origin. Coronary-subclavian steal syndrome was suspected, and the patient was referred for CMR for further evaluation.
Initial gradient echo imaging clearly showed the positions of the right IMA (RIMA) and the LIMA graft (Figure 1, Movie I). Phase-contrast velocity mapping of these 2 vessels in the transaxial plane (Figure 2, Movie II) showed antegrade caudally directed flow in the RIMA, but predominantly retrograde flow in the cranial direction in the LIMA (Figure 3). Contrast-enhanced magnetic resonance angiography was performed, which revealed occlusion of the proximal 2.5 cm of the left subclavian artery (Figure 4). Proximal left subclavian arterial occlusion and retrograde flow in the LIMA graft were convincing evidence of coronary-subclavian steal syndrome and accounted for the patient’s recurrent chest pain and myocardial perfusion abnormality. This case illustrates the versatility of CMR techniques for demonstrating this well-recognized complication after coronary artery bypass surgery with internal mammary grafts. The use of a variety of magnetic resonance techniques enables anatomic, functional, and flow information to be obtained in a single study.
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Figure 1. Gradient echo image in the transaxial plane showing the position of the LIMA graft embedded in the anterior mediastinal fat. The RIMA is indicated. AA indicates ascending aorta; PA, pulmonary artery; DA, descending aorta; and SVC, superior vena cava.
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Figure 2. Phase-contrast velocity map at midsystole in transaxial plane similar to that in Figure 1. Velocity is encoded in a through-plane direction so that cranially directed flow, such as in the ascending aorta (AA) and pulmonary artery (PA), is displayed as white pixels, whereas caudally directed flow, such as flow in the descending aorta (DA) and superior vena cava (SVC), is displayed as black pixels. In this image, flow in the RIMA is caudally directed (antegrade) and is therefore displayed as black. Conversely, flow in the LIMA is white and is therefore cranially directed (retrograde).
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Figure 3. Flow-versus-time curves obtained from phase-contrast velocity mapping of the LIMA and RIMA. The flow in these 2 vessels is in opposite directions.
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Figure 4. Contrast-enhanced magnetic resonance angiogram showing the aortic arch (AA) and the arch vessels in a right anterior oblique projection. The proximal segment of the left subclavian artery (LSA) does not enhance and is occluded. The arrowhead indicates the site of origin of the LSA. BCA indicates brachiocephalic artery; LCCA, left common carotid artery.
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Acknowledgments
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Disclosures
None.
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Footnotes
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The online-only Data Supplement, which contains 2 movies, can be found at http://circ.ahajournals.org/cgi/content/full/113/25/e930/DC1.
