Asian Cardiovasc Thorac Ann 1998;6:219-220
© 1998 Asia Publishing EXchange Pte Ltd
Side-Branch of Internal Mammary Artery Bypass Graft Causing Coronary Steal
Pasquale Mastroroberto, MD,
Massimo Chello, MD,
Saverio Zofrea, MD,
Roberto Ceravolo, MD1,
Francesco Perticone, MD1
Department of Cardiovascular Surgery
1 Department of Cardiology Catanzaro University Medical School Catanzaro, Italy
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For reprint information contact: Pasquale Mastroroberto, MD Corso Vittorio Emanuele 58 Salerno 84123, Italy Tel: 39 89 22 9039 Fax: 39 89 22 9039 Email: pasmas{at}general.it
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ABSTRACT
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A case of coronary steal syndrome caused by a large unligated branch of the left internal mammary artery in a patient who had undergone myocardial revascularization is described. The presence of recurrent angina, a positive exercise stress test, and repeat angiography showing a lateral branch of the mammary artery led to a diagnosis of the coronary steal phenomenon. Surgical ligation of the branch was performed and the patient became symptom-free with a negative exercise stress test.
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INTRODUCTION
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The superiority of the internal mammary artery (IMA) as a conduit for myocardial revascularization is well-established because of its better long-term patency compared with the long saphenous vein.1 With the increased use of the IMA, new complications have been seen such as the postoperative steal phenomenon caused by proximal subclavian stenosis with a pressure differential between the aorta and the IMA.2 However, coronary steal through an unligated side branch of the IMA has been reported only four times in the English literature and it has been treated by transcatheter coil embolization.3–6 This report describes another type of coronary steal due to a lateral branch of the left internal mammary artery (LIMA), which was treated surgically without sternotomy.
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CASE REPORT
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A 49-year-old male with coronary artery disease underwent elective coronary artery bypass grafting in 1996 at another institution. He received a LIMA graft to the left anterior descending coronary artery and a saphenous vein graft to the first obtuse marginal branch of the circumflex coronary artery. The patient had an uneventful recovery, returned to work, and progressed well for one month with medical therapy. Then he experienced effort-induced angina pectoris and atypical angina at rest. Five months later, he was admitted to our hospital with an initial diagnosis of graft occlusion. A thallium stress test showed ischemia in the territory of the left anterior descending coronary artery. Repeat coronary angiography demonstrated patency of the grafts and the presence of a large LIMA chest-wall branch with no subclavian stenosis (Figure 1
). After discussion between the cardiologists and cardiac surgeons, surgical treatment was decided.
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Figure 1. Coronary angiogram: selective cannulation of the left internal mammary artery (arrow) showing a large lateral branch (arrow).
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A small anterior incision at the 2nd left intercostal space was performed, the vessel was identified and ligated extrapleurally in less than 30 minutes. The patient was extubated on the operating table and became symptom-free. An angiographic study was proposed but the patient declined. Approximately 12 months after this operation, the patient was fully active without medical therapy except for aspirin. An exercise stress test was electrocardiographically and clinically negative. A recent evaluation after 18 months showed no angina and a negative exercise stress test.
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DISCUSSION
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The recurrence of angina and the angiographic findings of a patent LIMA graft, a patent vein graft, and the presence of a large lateral branch of the LIMA without evidence of a progression of coronary disease in the native vessels led us to diagnose a steal phenomenon. After anatomic analysis, we consider that this unligated side-branch corresponded to the lateral costal artery that can be found in 15% of patients and may be of similar caliber to the LIMA. Although the phenomenon of coronary steal seemed to be absent between the chest wall and the heart even though the LIMA blood flow could be diverted, the symptomatic relief and the negative exercise stress test obtained after the treatment support this diagnosis.7
As soon as the diagnosis of coronary steal syndrome was made, the choice of treatment had to be decided. The results in previous reports of transcatheter embolization are certainly interesting but incomplete and clearly show the need for experience and familiarity with the procedure.3–5 Our decision on the type of surgical management was based on avoidance of the difficulties of therapeutic embolization and the desirability of a safer and less invasive procedure. Only one similar case has been reported previously by Hijazi and colleagues8 whereby findings confirm the benefit of surgical treatment for this exceedingly rare occurrence.
Our experience highlights the importance of the harvesting of the LIMA by following up to the superior border of the first rib and ligating all the intercostal branches to ensure a good surgical result without recurrence of angina pectoris. The potential availability of the lateral costal artery and its easy accessibility suggests its usefulness as a bypass graft and extends the possibility myocardial revascularization with arterial conduits.
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REFERENCES
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Lytle BW, Loop FD, Cosgrove DM, Ratliff NB, Easley K, Taylor PC. Long-term (5 to 12 years) serial studies of internal mammary artery and saphenous vein coronary bypass grafts. J Thorac Cardiovasc Surg
1985;89:248–58.[Abstract]
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Brown AH. Coronary steal by internal mammary graft with subclavian stenosis. J Thorac Cardiovasc Surg
1977;73:690–3.[Abstract]
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Chavan A, Mugge A, Hohmann C, Amende I, Wahlers T, Galanski M. Recurrent angina pectoris in patients with internal mammary artery-to-coronary artery bypass: treatment with coil embolization of unligated side branches. Radiology
1996;200:433–6.[Abstract/Free Full Text]
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Ayres RW, Lu CT, Benzuly KH, Hill GA, Rossen JD. Transcatheter embolization of an internal mammary artery bypass graft side branch causing coronary steal syndrome. Cathet Cardiovasc Diagn
1994;31:301–3.[Medline]
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Ishizaka N, Ikari Y, Saeki F, et al. Repeat embolization of the side branch of the internal mammary artery by gelatin sponge particles and micro coils. Cathet Cardiovasc Diagn
1995;34:245–50.[Medline]
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Pelias AJ, DelRossi AJ, Tacy L, Wolpowitz A. A case of postoperative internal mammary steal [Letter]. J Thorac Cardiovasc Surg
1985;90:794–5.
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Reis SE, Gloth ST, Brinker JA. Assessment of the hemodynamic significance of a left internal mammary artery graft-pulmonary artery shunt in a post-bypass patient using a Doppler-tipped guide wire. Cathet Cardiovasc Diagn
1993;29:52–6.[Medline]
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Hijazi A, Mazhar R, Odeh S, Qunnaby I. Coronary steal through anomalous internal mammary artery graft treated by ligation without sternotomy. Tex Heart Inst J
1996;23:226–8.[Medline]
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ABSTRACT
INTRODUCTION
