Occlusion of both the left subclavian and the left anterior descending arteries caused retrograde flow through the internal thoracic artery to the distal subclavian ...
Case Reports
Dunja Latifi6-Jasni6, MD Darko Zorman, MD Andrej Cijan, MD, DSc Peter Rakovec, MD, DSc
Unusual Subclavian Steal Phenomenon A patient who had undergone myocardial revascularization with a saphenous vein graft to the left anterior descending artery and a left internal thoracic (mammary) artery graft to the 1st diagonal branch presented with an unusual form of subclavian steal syndrome. Occlusion of both the left subclavian and the left anterior descending arteries caused retrograde flow through the internal thoracic artery to the distal subclavian artery; the blood flow was supplied by the vein graft via the distal left anterior descending artery and diagonal branch. (Texas Heart Institute Journal 1994;21:236-7)
cubclavian steal syndrome is caused by occlusive disease of the proximal subclavian artery. In its classic presentation, blood is shunted, via the circle of Willis, retrograde from the vertebral artery to the distal subclavian artery. Since the emergence of the left internal thoracic (mammary) artery as the preferred graft vessel for direct myocardial revascularization (via anastomosis to the left anterior descending coronary artery), there have been a few published reports1"5 of steal syndrome as a result of blood shunting from the coronary artery to the internal thoracic artery, thence to the distal subclavian artery. In such an instance, the native coronary artery must be patent to allow retrograde blood flow through the internal thoracic artery. Here we present a case of a patient with occlusion of both the left subclavian and left anterior descending arteries, and an unusual blood flow through native coronary arteries and bypass grafts.
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Case Report had an anterior wall myocardial infarction in 1989. In the same year, she underwent coronary bypass surgery with a saphenous vein graft to the left anterior descending artery and a left internal thoracic artery graft to the 1st diagonal branch. Three years later, she presented with progressive angina. Repeat coronary angiography demonstrated occlusion of the left anterior descending artery and a significant stenosis of the left circumnflex artery. The saphenous vein graft to the left anterior descending artery was patent and supplied also the diagonal branch and (by reverse flow) the internal thoracic and subclavian arteries (Fig. 1). The stenosis in the diagonal branch that had seemed to be significant on the initial angiogram before bypass surgery was now found to be minor. (During the 1st study, diminished blood flow through the narrowed left anterior descending artery had led to bad visualization of the diagonal branch.) Aortic arch angiography demonstrated occlusion of the left subclavian artery (Fig. 2). The patient underwent left circumflex angioplasty; thereafter, arteriography demonstrated excellent radiographic improvement in the caliber of this artery and the patient became asymptomatic. In order to determine whether it was also feasible to bypass the occlusion of the left subclavian artery, she was readmitted and repeat aortic arch angiography was performed, together with selective left carotid angiography. In addition to occlusion of the left subclavian artery, this study revealed a 40% stenosis at the origin of the left carotid artery and retrograde flow through the left vertebral artery. The patient refused any other invasive therapeutic measures. Therefore, for the time being, we are abstaining from any other procedures.
A 63-year-old
Key words: Angioplasty, percutaneous transluminal coronary; internal mammary-coronary artery
anastomosis; subclavian steal syndrome From: Clinic of Cardiology, University Medical Centre, 61105 Ljubljana, Slovenia Address for reprints: Peter Rakovec, MD, DSc, Clinic of Cardiology, Zalogka 7, 61105 Ljubljana, Slovenia
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Unusual Subclavian Steal Phenomenon
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Volume 21, Number 3, 1994
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Fig. 1 Coronary angiogram (left anterior oblique). The angiographic catheter cannulates the saphenous bypass graft to the left anterior descending artery. Observe the retrograde blood flow through the internal thoracic artery via the diagonal branch. Arrows: 1 = catheter; 2 = saphenous bypass graft; 3 = left anterior descending artery; 4 = diagonal branch; 5 = internal thoracic artery
Comments As a consequence of the widespread use of the left intemal thoracic artery for myocardial revascularization, the number of patients with recurrent coronary symptoms related to subclavian artery obstruction will increase. Atherosclerosis in the subclavian artery is much more common than in the internal thoracic artery graft. Symptomatic coronary and cerebral steal after internal mammary-coronary bypass already has been described.' The treatment of choice is either carotidsubclavian artery bypass' or percutaneous transluminal coronary angioplasty.2'3 In our patient, we noted a complex steal syndrome with retrograde flow through native coronary arteries and venous and arterial grafts. The steal phenomenon in this case appears to have been asymptomatic. It is hard to imagine how dilating the circumflex artery could have had any effect on the steal pathway, since the left anterior descending artery was totally occluded, leaving the left main and circumflex arteries an isolated system. For any appreciable steal from the left anterior descending artery to occur via the diagonal-branchto-internal-thoracic artery connection, the lesion in
Texas Heart Instituteiburnal
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Fig. 2 Aortic arch angiogram, showing occlusion of the left subclavian artery (arrow) and stenosis at the origin of the left common carotid artery.
the diagonal branch would have to be a low-grade stenosis. A high-grade stenosis would have minimized the steal's flow. The steal syndrome might have been asymptomatic because the stenosis in the diagonal branch served as a protective mechanism. On the other hand, the distal segment of the left anterior descending artery after anastomosis of the graft was nearly occluded, which would tend to favor blood flow to the diagonal artery and enhancement of the steal.
References 1. Bashour TT, Crew J, Kabbani SS, Ellertson D, Hanna ES, Cheng TO. Symptomatic coronary and cerebral steal after internal mammary-coronary bypass. Am Heart J 1984;108: 177-8. 2. Soulen MC, Sullivan KL. Subclavian artery angioplasty proximal to a left intemal mammary-coronary artery bypass graft: case report. Cardiovasc Intervent Radiol 1991;14:355-7. 3. Shapira S, Braun SD, Puram B, Patel G, Rotman H. Percutaneous transluminal angioplasty of proximal subclavian artery stenosis after left internal mammary to left anterior descending artery bypass surgery. J Am Coil Cardiol 1991;18: 1120-3. 4. Amar D, Attai LA, Gupta SK, Jones A. Perioperative diagnosis of subclavian artery stenosis: a contraindication for internal mammary artery-coronary artery bypass graft. Anesthesiology 1990;73:783-5. 5. Amar D, Attai LA, Gupta SK, Jones A. Bilateral upper extremity blood pressure measurements should be routine prior to coronary artery surgery [letter]. Chest 1992;101:882.
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