Ann Thorac Surg 2000;69:1865-1866
© 2000 The Society of Thoracic Surgeons
Original articles: Cardiovascular
Incidence and size of lateral costal artery in 103 patients
Fraser W.H. Sutherland, FRCSa,
Jatin B. Desai, FRCSa
a Cardiothoracic Unit, Kings College Hospital, London, England, United Kingdom
Address reprint requests to Dr Sutherland, Department of Cardiothoracic Surgery, The Royal Infirmary of Edinburgh, Ward 17, Edinburgh EH3 9YW Scotland
e-mail: fs{at}frasersutherland.demon.co.uk
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Abstract
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Background: The internal mammary artery is used widely as a conduit for coronary artery bypass grafting. Most practicing cardiac surgeons are unaware of an aberrant side branch, the lateral costal artery (LCA), that arises proximally. Unligated, this side branch has been held responsible for early recurrence of angina in a small number of patients in the literature. In this study we identified the incidence and length of the LCA.
Methods: We studied 103 patients who had coronary artery bypass grafting with bilateral internal mammary arteries. The presence or absence of an LCA was noted, and a record was made of the number of intercostal spaces traversed.
Results: Thirty-one of 103 patients had an LCA on one or the other side. Twenty-five patients had bilateral LCAs in which length was equal on both sides in 18. Median length was two intercostal spaces (range, one to six). The LCA extended to the fifth space or beyond in 5 patients.
Conclusions: The LCA was present in one third of patients who had coronary artery bypass grafting. A few patients had vessels sizable enough to raise concerns about recurrence of angina. It is prudent to exclude the presence of an LCA in all patients who have cardiac operations.
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Introduction
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The internal mammary artery is used widely as a conduit for coronary artery bypass grafting. Despite familiarity with its usual course and branches from repeated experience in the operating theater, many surgeons are unaware of an aberrant proximal side branch, the lateral costal artery (LCA). This vessel is inconsistent in both its presence and size. The present study was undertaken to identify the incidence of the LCA and variation in its length in patients who had coronary artery bypass grafting in our surgical unit.
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Material and methods
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We studied 103 consecutive patients who had coronary artery bypass grafting using bilateral internal mammary arteries during a 6-month period. The pleura was opened widely during the course of internal mammary artery (IMA) dissection. There were no significant pleural adhesions in any patients. It was therefore possible to visualize the inside of the chest wall up to the origin of the IMA on both sides (Fig 1). We recorded the presence or absence of a lateral costal branch. In patients who had an LCA, the length was recorded by reference to the number of intercostal spaces traversed. Data are expressed in absolute numbers, which approximate to percentages.
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Fig 1. The right lateral costal artery seen from the surgeon’s perspective on the lateral chest wall through the opened right pleura.
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Results
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Thirty-one of 103 patients (30%) had a lateral costal branch on one side or the other. Twenty-five of the 31 patients had an LCA bilaterally, and 6 patients had an LCA on one side only. In 18 of the 25 patients with bilateral LCA the length was equivalent on both sides, and in 7 patients the length was different. Median length was two intercostal spaces (range, one to six intercostal spaces). In 5 patients the LCA extended to the fifth intercostal space or beyond (Fig 2).
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Fig 2. Variations in the length of the lateral costal artery, expressed as the number of intercostal spaces traversed.
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Comment
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The internal mammary artery is widely held to be the conduit of choice for revascularization of the left anterior descending artery. It characteristically gives rise to a number of named branches, including the pericardiacophrenic, anterior intercostal, sternal, and perforating vessels, with which most cardiac surgeons are familiar. Traditional surgical practice has been to divide all branches. However, with the advent of limited-access approaches to coronary operations, this traditional axiom has been questioned, and some surgeons have been satisfied with leaving the proximal artery undissected and side branches therefore undivided. The question of whether side branches should be ligated remains controversial and unanswered. On one hand, there are a number of compelling case histories [1, 2, 3] in which early recurrence of angina has been attributed to large unligated IMA side branches (Fig 3). In those patients obliteration of the offending vessel has eradicated or markedly improved anginal symptoms. Conversely, some groups have suggested that persistence of IMA branches does not influence postoperative blood flow in the left anterior descending artery [4]. The present study did not seek to answer that question but rather to identify the incidence of one particular side branch that is inconsistent in its presence and size, so that surgeons can logically approach dissection of the proximal IMA. This vessel, the lateral costal artery, is not mentioned in many of the standard anatomic textbooks or in much of the early anatomic descriptions of the IMA in the surgical literature. A recent, detailed, and fairly comprehensive anatomic study [5] found the incidence of the LCA in cadavers to be 15%. In only 5% of them was the vessel found bilaterally. Their results vary slightly from our own, which suggest a higher incidence and more symmetry, with it being present in one third of our patients and bilateral in roughly half of those cases. These differences might be attributable to different patient populations. The former study did not comment on size of the LCA, which we believe to be most important. There is great variation in the vessel’s length, and many of the branches that were blamed for recurrence of angina in the case histories mentioned earlier would seem to be large lateral costal arteries despite being variously named by those authors as "large first intercostal" or "large pectoral branch." It is unusual for the LCA to be especially sizable, as it extended to the fifth space or beyond in only 5 patients. In these patients it might be usable as a conduit in its own right. Its proximal origin, however, would create a problem for length. It is our belief that to minimize recurrence of angina, the rare but finite incidence of a sizable LCA should be sought actively in all patients who have coronary artery bypass grafting. This can be done by IMA angiography at the time of coronary angiography or by careful and complete exposure during surgical dissection. We favor the latter approach, as complete dissection of the IMA also maximizes its useful length, which is especially important in bilateral IMA grafting.
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Fig 3. The left lateral costal artery seen at angiography arising from the left internal mammary artery in a patient presenting with recurrence of angina after coronary artery bypass grafting.
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References
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Nakhjavan K.F., Koolpe H.A., Bruss J., Najmi M., Radke T. Transcatheter coil occlusion for treatment of left internal mammary-anterior descending artery steal phenomenon. Cathet Cardiovasc Diagn 1993;28:347-350.[Medline]
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Sbarouni E., Corr L., Fenech A. Microcoil embolization of large intercostal branches of internal mammary artery grafts. Cathet Cardiovasc Diagn 1994;31:334-336.[Medline]
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Chavan A., Mugge A., Hohmann C., Ammende I., Wahlers T., Gelanski M. Recurrent angina pectoris in patients with internal mammary artery to coronary artery bypass. Radiology 1996;200:433-436.[Abstract/Free Full Text]
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Henriquez-Pino J.A., Gomes W.J., Prates J.C., Buffolo E. Surgical anatomy of the internal thoracic artery. Ann Thorac Surg 1997;64:1041-1045.[Abstract/Free Full Text]
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Luise R., Teodori G., Di Giammarco G., et al. Persistence of mammary artery branches, and blood supply to the left anterior descending artery. Ann Thorac Surg 1997;63:1759-1764.[Abstract/Free Full Text]
Accepted for publication December 22, 1999.
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Abstract
Introduction
