A 78-year-old woman with multiple risk factors for atherosclerotic disease presented at the emergency department with dysarthria, difficulty coordinating hand movements, and dyspnea on exertion. After an evaluation, a left carotid endarterectomy was planned. A preoperative stress test revealed a reversible anteroseptal defect. Cardiac catheterization showed severe native-vessel coronary disease, normal left ventricular function, origin of the left internal thoracic artery (LITA) from the distal third of the subclavian artery, and at least a 50% stenosis of the mid-portion of the LITA (Fig. 1).
Fig. 1 Angiography of the left internal thoracic artery shows the area of stenosis (arrow A) and the origin of the artery from the distal left subclavian artery (arrow B).
After the left carotid endarterectomy, re-exploration was required because of bleeding. Six days later, the patient underwent coronary artery revascularization. For bypass, we used reverse saphenous vein grafts to the left anterior descending artery and the right coronary artery. The LITA was not used because of its anomalous origin and its mid-portion stenosis. The circumflex vessels were too small for surgical revascularization. The patient was discharged from the hospital on postoperative day 6.
Comment
Aziz and Ramsdale1 state that the incidence of LITA anomalies is low and that subclavian angiography should be performed only in symptomatic patients; however, other authors disagree.
In a study of 130 patients, Feit and colleagues2 found that 4% to 5% of the internal thoracic arteries (ITAs) were unusable for bypass due to stenosis or small size and concluded that radiographic evaluation of the ITA during diagnostic catheterization is important. Bauer and coworkers3 evaluated 262 patients and found that 2.7% of the ITAs were unsuitable as conduits. Henriquez-Pino and associates4 reported a 1% occurrence of lateral origin of the ITA, a situation that can subject the vessel to damage during dissection or subclavian venipuncture.
Had the LITA been used as an in situ graft in our patient, the risk of early graft failure or continued coronary ischemia would have been high. When it is known that the LITA has an aberrant origin or is stenotic, the surgeon can plan to use another arterial graft, a saphenous vein graft, or a free LITA. We recommend subclavian and LITA angiography in patients who have coronary artery disease that could require surgery.
Acknowledgments
The authors wish to thank the Lewis B. Flinn Library staff and Nanci Catinella for their assistance in the preparation of the manuscript, Cynthia J. Clendenin for medical editing, and Darryn Neujahr and Douglas Bugel for their assistance with the medical images.
Footnotes
Address for reprints: Ray A. Blackwell, MD, 4755 Ogletown-Stanton Road, P.O. Box 6001, Newark, DE 19718. E-mail: rblackwell@christianacare.org
References
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