Ann Thorac Surg 1995;60:186-188
© 1995 The Society of Thoracic Surgeons
Case Reports
Revascularization of the Internal Mammary Artery After Coronary Artery Bypass Grafting
Stanley A. Gall, Jr, MD,
Clarence H. Owen, MD,
Fiona M. Clements, MD,
Richard L. McCann, MD
Departments of Surgery and Anesthesiology, Duke University Medical Center, Durham, North Carolina
Accepted for publication November 12, 1994.
 |
Abstract
|
|---|
Symptomatic anterior myocardial ischemia as a result of stenosis at the origin of the left internal mammary artery developed in a patient who underwent prior coronary artery bypass grafting using the left internal mammary artery as a conduit. Successful revascularization of the left anterior descending coronary artery was achieved using a reversed saphenous vein bypass graft from the left common carotid artery to the proximal internal mammary artery. This approach provided myocardial revascularization and avoided reoperative median sternotomy.
|
Introduction
|
|---|
The internal mammary artery (IMA) is the preferred conduit for myocardial revascularization because of its superior long-term patency [1]. Although the IMA itself enjoys a relative resistance to atherosclerotic involvement [2], myocardial perfusion through this conduit may be compromised by obstructive disease in the proximal subclavian artery, by disease at the origin in the IMA itself or at the anastomosis of the IMA and the coronary artery, or by progression of distal disease in the native coronary circulation. An alternative approach to reoperative myocardial revascularization using common carotid to IMA bypass for proximal atherosclerotic stenosis of the IMA is described.
A 69-year-old man underwent coronary artery bypass grafting in 1986, 3 years after left carotid endarterectomy, with saphenous vein grafting to the right, left circumflex, and anterolateral coronary arteries, and left IMA anastomosis to the left anterior descending coronary artery. He remained free of angina until 1994 when new-onset Canadian Cardiovascular Society class IV angina developed. An exercise tolerance test was limited by anterolateral ST-segment depression in stage I of the Bruce protocol. Cardiac catheterization demonstrated a 75% stenosis of the IMA at its origin (Fig 1
). Because of the overall excellent condition of the saphenous vein grafts and absence of significant disease in the native vessels distal to the coronary artery bypass anastomoses, repair or bypass of the IMA stenosis was considered in lieu of repeat coronary artery bypass grafting. Exercise thallium testing demonstrated a reversible perfusion defect in the left anterior descending coronary artery distribution, which was associated with the patient's angina. Arch arteriography suggested atheromatous involvement of the subclavian with no major stenosis and demonstrated a normal left common carotid artery.
View larger version (91K):
[in this window]
[in a new window]
|
Fig 1. . The high-grade stenosis of the left internal mammary artery is demonstrated at its origin from the left subclavian artery.
|
|
Preoperative preparations included adhesive defibrillator pads applied to the chest and invasive pressure monitoring. The neck, chest, abdomen, groins, and right leg were included in the sterile field. The left femoral artery was cannulated percutaneously to provide access in the event that emergent intraaortic balloon pump insertion was required. A transverse left supraclavicular incision was performed (Fig 2A), the lateral head of the sternocleidomastoid was retracted medially, and the scalenus anterior was divided at its origin to expose the left subclavian vein (Fig 2B). The thoracic duct was ligated and divided, allowing the subclavian vein to be retracted inferiorly. The subclavian artery was exposed after carefully noting the course of the phrenic nerve. The internal mammary artery was isolated distally for a distance of 3 cm. The angiographically significant atherosclerotic involvement of the subclavian artery, confirmed by direct inspection and palpation, made the artery unsuitable for graft inflow. The common carotid artery was soft, elastic, and without atherosclerotic involvement.
View larger version (33K):
[in this window]
[in a new window]
|
Fig 2. . (A) Site of left supraclavicular incision. (B) Supraclavicular exposure of the left internal mammary artery and anastomotic sites. (C) Completed common carotid to internal mammary artery bypass graft with reversed saphenous vein graft. (a = artery; mus = muscle; n = nerve.)
|
|
Transesophageal echocardiography demonstrated that the normal left ventricular anterior wall motion degenerated to mild hypokinesis with a test occlusion of the IMA. Subsequent IMA clamping after beginning a nitroglycerin infusion caused no deterioration of anterior wall motion. Inspection of the opened proximal IMA confirmed the proximal stenosis as an atherosclerotic plaque. The proximity of the thyrocervical trunk and the disparity in thickness between the delicate IMA and the grossly diseased subclavian artery precluded patch angioplasty. The previously harvested greater saphenous vein graft was anastomosed end to side to the IMA with a running 7-0 polypropylene suture. No dysrhythmias or electrocardiographic abnormalities were present after clamp removal. Intraoperative arteriography with the saphenous vein graft demonstrated a widely patent anastomosis and confirmed IMA patency. The vein graft was trimmed and anastomosed to a 4.5-mm punch arteriotomy in the common carotid artery (Fig 2C
). Excellent flow was palpable within the graft.
Extubation was accomplished immediately in the operating room. Postoperative recovery was free of neurologic or cardiac sequelae. On postoperative day 4, thallium scanning was repeated. Exercise induced no angina and myocardial perfusion remained normal.
|
Comment
|
|---|
The IMA has been firmly established as the conduit of choice for coronary revascularization. Patency rates at 10 years have been documented at 80% to 90% [1]. The IMA is relatively free from direct involvement with atherosclerosis [2, 3]; however, its ability to perfuse the myocardium may be compromised by progressive atherosclerosis in other vessels. Although atherosclerotic stenoses within the body of the IMA are rare, anastomotic stenoses develop with greater frequency. These stenoses are a result of intimal hyperplasia or a technically inadequate anastomosis. Percutaneous transmammary angioplasty has been successful in treating both anastomotic stenosis and progressive atherosclerotic coronary disease distal to the anastomosis [4, 5]. Angioplasty at the IMA anastomosis is successful in 90% to 95% of cases with no reports of distal embolization and 90% to 100% freedom from cardiac morbidity or mortality. Angiographic follow-up, although not complete in all series, demonstrates a restenosis rate of 10% to 20% at 6 months, which is less than the expected rate after angioplasty of saphenous vein graft stenoses [4, 5]. Although angioplasty with or without stenting may be applied to stenoses at the ostium of the IMA itself, reports of this technique are limited [6, 7]. Angioplasty was not offered in this case because of the prior experience, at this institution, of arterial dissection from angioplasty of ostial IMA lesions.
Thus, the available choices for this patient with unstable angina were limited to either reoperative sternotomy with new vein graft replacement of the IMA and possibly of all the old saphenous grafts, or local IMA repair. The risk to the intact, well-functioning grafts as well as the overall increased risk of reoperative sternotomy was felt to be too great to offer redo coronary artery bypass grafting. Therefore, direct revascularization was left as the preferred alternative. We undertook several precautions in our preoperative management. Safety precautions included selection of an experienced cardiac anesthesiologist, placement of adhesive defibrillator pads, use of a pacing capable pulmonary artery catheter to facilitate ventricular pacing for symptomatic bradycardia, placement of a femoral arterial catheter to facilitate emergent intraaortic balloon pump placement, and preparing an inclusive sterile field to allow for saphenous vein harvesting and emergent median sternotomy. Transesophageal echocardiography visualized ventricular systolic wall thickening in the region of the left anterior descending coronary artery that was supplied here by the IMA. The mild hypokinesis of the anterior wall that occurred with test clamping of the IMA indicated that a 10- to 15-minute period of clamping required to repair the IMA would be well tolerated. The supraclavicular incision afforded optimal exposure of the left subclavian artery, IMA, and common carotid arteries. Resection of the medial third of the clavicle is an option to provide further improvement in exposure, but was not needed.
A patient who had recurrent angina attributable to proximal stenosis of the internal mammary artery was treated by revascularization with a saphenous vein graft. This revascularization was accomplished with a supraclavicular incision, avoiding a reoperative median sternotomy. Careful attention to detail in preoperative and perioperative management contributed to the success of this procedure.
|
Footnotes
|
|---|
Address reprint requests to Dr Gall, Duke University Medical Center, PO Box 31083, Durham, NC 27710.
|
References
|
|---|
- Grover FL, Johnson RR, Marshall G, et al. Impact of mammary grafts on coronary bypass operative mortality and morbidity. Ann Thorac Surg 1994;57:559–69.[Abstract]
- Sisto T, Isola J. Incidence of atherosclerosis in the internal mammary artery. Ann Thorac Surg 1989;47:884–6.[Abstract]
- Mestres CA, Rives A, Igual A, Vehi C, Murtra M. Atherosclerosis of the internal mammary artery. Histopathological analysis and implications on its results in coronary artery bypass graft surgery. Thorac Cardiovasc Surg 1986;34:356–8.[Medline]
- Sketch MH, Quigley PJ, Perez JA, et al. Angiographic follow-up after internal mammary artery graft angioplasty. Am J Cardiol 1992;70:401–3.[Medline]
- Shimshak TM, Giorgi LV, Johnson WL, et al. Application of percutaneous transluminal coronary angioplasty to the internal mammary artery graft. J Am Coll Cardiol 1988;12:1205–14.[Abstract]
- Vivekaphirat V, Yellen SF, Foschi A. Percutaneous transluminal angioplasty of a stenosis at the origin of the left internal mammary artery graft: a case report. Cathet Cardiovasc Diagn 1988;15:176–8.[Medline]
- Almagor Y, Thomas J, Colombo A. Balloon expandable stent implantation of a stenosis at the origin of the left internal mammary artery graft: a case report. Cathet Cardiovasc Diagn 1991;24:256–8.[Medline]
This article has been cited by other articles:
|
|
|
|
 
E. Prifti, M. Bonacchi, G. Frati, and G. Giunti
Reoperative revascularization of an occluded left subclavian artery and left internal mammary artery ostial stenosis
Eur. J. Cardiothorac. Surg.,
January 1, 2002;
21(1):
108 - 110.
[Abstract]
[Full Text]
[PDF]
|
|
|
Top
Abstract
Introduction
