Ann Thorac Surg 2000;70:663-665
© 2000 The Society of Thoracic Surgeons
Case report
Retrocardiac arteriovenous malformation causing recurrent cerebral ischemia
Thomas Busch, MDa,
Ivan Aleksic, MDa,
Friederike Schulze, MDb,
Horia Sirbu, MDa,
Harald Dalichau, MD, PhDa
a Departments of Thoracic and Cardiovascular Surgery Georg-August-University, Göttingen, Germany
b Department ofCardiology, Georg-August-University, Göttingen, Germany
Address reprint requests to Dr Busch, Department of Thoracic and Cardiovascular Surgery, Georg-August-Universität Göttingen, Robert-Koch-Str 40, 37075 Göttingen, Germany
e-mail: tbusch{at}gwdg.de
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Abstract
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A 28-year-old woman had been suffering from recurrent cerebral embolizations for almost 9 years. A retrocardiac arteriovenous malformation was identified as the source of emboli. It was supplied by chest wall veins and the right upper pulmonary vein, connected to the back wall of the left atrium and a possibly aberrant hepatic vein originating from the abdomen. The aneurysm was resected and all supplying veins ligated. The vein from below the diaphragm was implanted into the right atrium. Her postoperative course was uncomplicated. Long-term follow-up free from cerebrovascular events.
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Introduction
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Arteriovenous (AV) fistulas represent abnormal connections between arteries and veins, bypassing the capillary bed. Congenital fistulas result from a maldevelopment of the common embryonic basis of arteries and veins [1]. The occurrence of congenital AV fistulas has been described in all parts of the body, mainly the head, extremities, and visceral organs [2]. Most thoracic AV fistulas are pulmonary AV fistulas as initially reported by Churton in 1897 [3]. However, other thoracic fistulas have been described [4]. We present a young woman with ischemic lesions of the cerebellum due to recurrent emboli from an arteriovenous aneurysm located in the posterior mediastinum.
A patient was admitted to our hospital with vertigo, profuse sweating, right-sided Horner’s syndrome, paralysis of branches of the facial nerve, right-sided paresis of the uvula, hoarseness, and dysphagia due to vagal dysfunction for the first time at the age of 19. Neurological examination revealed a cerebellar lesion in the area of the inferior posterior cerebellar artery. All studies initiated to identify the source of embolization were negative. So were all laboratory studies aimed at identifying a hypercoagulable state.
The patient’s previous medical history was remarkable for a magnetic resonance imaging scan of the chest 5 years before, at the age of 14, which had shown an unusual retrocardiac tumor. A relationship with the girl’s neurologic deficits was not considered at that time.
Two years after her initial presentation to our hospital, at the age of 21, the girl experienced transitory ischemic attacks and was diagnosed to have an occluded left internal carotid artery without ever having had a stroke. An external/internal carotid artery-bypass was implanted without improvement of her neurological symptoms.
Follow-up studies 1 year later, at the age of 22, showed a left-sided stroke in the area of the medial cerebral artery but no further morphologic changes of the brain. Another year later, she was admitted to the hospital due to embolic occlusion of the left central retinal artery. At this point, the retrocardiac tumor was linked to her frequent embolizations and further diagnostic tests were ordered.
Transthoracic and transesophageal echocardiography confirmed a retrocardiac tumor of unknown etiology. Right and left heart catheterization were unremarkable. Computed tomographic scans showed a vascular malformation in the posterior mediastinum, possibly connected to the left atrium (Fig 1). Venous vessels supplying this malformation originating from below the diaphragm could not definitely be excluded (Fig 2). The patient was suspected to have a systemic-venous malformation possibly connected with the right lower pulmonary vein and communicating with the left atrium. Pulmonary angiography showed widened right-sided pulmonary veins only. Differential diagnosis included lung sequester and an AV malformation of the vena azygos-hemiazygos-system.
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Fig 1. Computed tomographic scan of the chest demonstrating a retrocardiac arteriovenous (AV) aneurysm communicating with the back wall of the left atrium (arrow).
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Fig 2. Computed tomographic scan of the chest demonstrating venous supply vessels of the malformation above the diaphragm (arrow).
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The patient was scheduled for surgery and underwent a right-sided anterolateral thoracotomy. An AV aneurysm was found in the posterior mediastinum. It reached from dorsal of the inferior vena cava behind the hilus of the right lung up to the azygos vein. Several veins supplying blood from the chest wall and multiple small vessels communicating with the right upper pulmonary vein and a large connection with the back wall of the left atrium were identified. Another large venous vessel was identified which originated from the abdomen and penetrated the diaphragm separately (Fig 3).
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Fig 3. Anatomical-topographical drawing of retrocardiac arteriovenous (AV) aneurysm in an anterior–posterior plane. (VCS = vena cava superior; AVA = arteriovenous aneurysm; A = pulmonary artery; V = vein; C = communication to the back wall of the LA; LA = left atrium; RA = right atrium; RV = right ventricle.)
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All vessels were ligated and divided. The connecting part to the left atrium was oversewn without extracorporeal circulation. The AV aneurysm was resected in toto. As we were not able to determine the origin of the large vein coming from below the diaphragm, it was mobilized and separately implanted into the right atrium.
The postoperative course was uneventful and the patient was discharged on postoperative day 10. She has been followed by our outpatient clinic for the last 5 years on an annual basis and has not had any more transitory ischemic attacks.
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Comment
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Congenital AV fistulas frequently become symptomatic during the second and third decade of life. Cardiac manifestations are rare. Appropriate therapy is difficult in particular regarding surgical intervention because of the technical difficulties frequently encountered and the high rate of recurrent fistulas. The indication for surgical therapy is generally accepted for pulmonary AV fistulas [5], coronary fistulas and their complications [6], and fistulas originating from the internal mammary artery [7]. Apart from conservative approaches, percutaneous intraarterial embolization of AV fistulas has been attempted with good results [8]. This patient was not considered for conservative treatment because of recurrent emboli which had caused multiple cerebral infarcts, transitory ischemic attacks, and occlusion of the left internal carotid artery. Percutaneous intraarterial embolization was ruled out because of the uncertain preoperative diagnosis, the high likelihood of a connection with the left atrium, and the difficulties to reach this particular AV aneurysm.
In case of diagnoses with a grave prognosis, like recurrent cerebral ischemia, any possible source of emboli should be excluded, in particular in a young patient as described herein. Very rare diseases have to be considered as well in order to create a reasonable therapeutic concept for the patient. We conclude that, if the patient is free from symptoms, regular follow-up seems justified. However, in case of cardiac or embolic complications due to AV fistulas, surgical intervention is the therapy of choice.
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References
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Accepted for publication December 18, 1999.
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Abstract
Introduction
