Ann Thorac Surg 2000;69:1929-1931
© 2000 The Society of Thoracic Surgeons
Case reports
A continuous murmur after surgery for dissecting ascending aortic aneurysm
Kwan-Leung Chan, MDa
a University of Ottawa Heart Institute, Ottawa, Ontario, Canada
Address reprint requests to Dr Chan, University of Ottawa Heart Institute, 40 Ruskin St, Ottawa, ON, K1Y 4W7, Canada
e-mail: kchan{at}ottawaheart.ca
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Abstract
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We report a case of a subcutaneous arteriovenous fistula that developed after aortic surgery. A careful physical examination and the selective use of imaging tests can differentiate this relatively benign complication from the more serious causes of a continuous murmur in this setting.
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Introduction
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Dissection involving the ascending aorta is a life-threatening condition that requires prompt diagnosis and timely intervention [1, 2]. Surgical repair involves the resection of the diseased aorta with interposition of a graft conduit. This type of surgery is technically demanding because the aortic tissue is usually very fragile. A number of complications have been reported with the different types of aortic repair [3, 4], and a new continuous murmur following aortic repair suggests the development of a fistula originating from the aortic graft.
We recently encountered a patient who developed a continuous murmur as a result of an unusual complication following the surgical resection of the ascending aorta.
A 70-year-old woman had sudden onset of chest pain for 2 weeks. Her chest radiograph showed a widened mediastinum and a computed tomogram demonstrated the presence of an ascending aortic aneurysm with a strong suspicion of an intimal flap within the aortic root. The localized dissection involving the aortic root was confirmed by transesophageal echocardiography, which also showed mild aortic regurgitation, although no murmurs were detected on auscultation. She had resection of the ascending aortic dissection and interposition of an aortic graft. Her aortic valve was preserved. Her postoperative course was uncomplicated. On her follow-up visit 6 months after discharge, a grade 3 continuous murmur was heard along the right sternal border loudest over the first right intercostal space. There was no evidence of heart failure. An urgent transesophageal echocardiogram showed that both the proximal and distal anastomotic sites of the aortic graft were intact with no evidence of a pseudoaneurysm or a fistula, and only mild aortic regurgitation was present.
On a repeat physical examination, prominent superficial veins over her right chest were detected (Fig 1). The patient confirmed that these veins developed after the aortic surgery. Furthermore, the continuous murmur disappeared when the stethoscope was pressed firmly against the chest wall at the first right intercostal space.
A computed tomogram of the chest showed that the ascending aortic graft was normal and there was no intracardiac fistula. There was a large subcutaneous vessel measuring 7 mm in diameter at the right anterior chest adjacent to the sternum near the first right intercostal space (Fig 2). A more caudal slice showed dilated veins within the right pectoral muscles and over the right anterior chest and breast (Fig 3).
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Fig 2. Computed tomogram of the chest just above the aortic arch showed a dilated subcutaneous artery (arrow) measuring 7 mm in diameter at the right anterior chest wall adjacent to the sternum.
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Fig 3. Computed tomogram of the chest at a more caudal level showed dilated blood vessels (arrows) within the right pectoral muscles and over the right anterior chest and breast.
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Comment
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Aortic surgery to repair a dissecting aortic aneurysm is technically demanding because the aortic tissue is usually friable such that sutures may pull through. The development of a pseudoaneurysm at the proximal anastomotic site of an aortic graft is a well-recognized complication of this type of surgery [3, 4]. This pseudoaneurysm can further lead to the development of an aortocameral fistula giving rise to a continuous murmur [5]. This complication can result in heart failure and its correction requires complicated surgical repair.
In our patient, the continuous murmur was caused by a subcutaneous arteriovenous fistula, which developed as a result of the sternotomy. Because of its subcutaneous nature, the arteriovenous fistula produces a very prominent continuous murmur that can be confused with the more serious complication of an aortocameral fistula [5]. Another rare cause of a continuous murmur is the iatrogenic creation of an aortocoronary vein fistula during coronary artery bypass graft surgery [6]. The appearance of unilateral superficial veins over the chest should be a useful clue to the development of this relatively benign complication. Disappearance of the continuous murmur upon local compression along the sternal border not only confirms the diagnosis but can also be used to localize the arteriovenous fistula. The presence of this particular physical finding in our opinion obviates the need for further investigations. We suspect that this type of complication may well have been recognized previously in view of the large number of cardiac operations that are being performed, but we could find no other report.
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References
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Crawford E.S. The diagnosis and management of aortic dissection. JAMA 1990;264:2537-2541.[Abstract/Free Full Text]
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DeSanctis R.S., Doroghazi R.M., Austen W.G., Buckley M.J. Aortic dissection. N Engl J Med 1987;317:1060-1067.[Medline]
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Lewis C.T.P., Cooley D.A., Murphy M.C., Talledo O., Vega D. Surgical repair of aortic root aneurysms in 280 patients. Ann Thorac Surg 1992;53:38-46.[Abstract]
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Svensson L.G., Crawford E.S., Hess K.R., Coselli J.S., Safi J.H. Dissection of the aorta and dissecting aortic aneurysms. Improving early and long-term surgical results. Circulation 1990;82(Suppl 4):24-38.
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Lindsay J., Jr Aortocameral fistula. Am Heart J 1993;125:441-443.
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Starling M.R., Groves B.M., Frost D., Toon R., Arom K.V. Aorto-coronary vein fistula. Chest 1981;79:64-68.[Abstract/Free Full Text]
Accepted for publication October 19, 1999.
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Abstract
Introduction
