AJR 2004; 183:1239-1240
© American Roentgen Ray Society
CT of a Ruptured Vein Graft Pseudoaneurysm: An Unusual Cause of Superior Vena Cava Obstruction
Eoin C. Kavanagh1,
Gormlaith Hargaden,
Fidelma Flanagan and
John G. Murray
1 All authors: Department of Radiology, Mater Misericordiae Hospital, Eccles
St., Dublin 7, Ireland.
Received January 19, 2004;
accepted after revision February 16, 2004.
Address correspondence to E. C. Kavanagh
(eoinkav{at}yahoo.com).
Introduction
We describe a case of acute superior vena cava obstruction caused by
the rupture of a pseudoaneurysm in a coronary artery bypass saphenous vein
graft. The common causes of superior vena cava obstruction include carcinoma
of the bronchus, mediastinal mass, mediastinal fibrosis, and constrictive
pericarditis [1]. Rupture of a
coronary artery bypass vein graft is an uncommon but well-described
complication of coronary artery bypass surgery. The presence of a
pseudoaneurysm in a coronary artery bypass vein graft is an important
radiologic diagnosis to make because early endovascular or surgical repair can
prevent a catastrophic rupture
[2].
Case Report
A 55-year-old man presented with acute onset of chest pain and dyspnea. At
physical examination, he exhibited signs of superior vena cava
obstruction—engorgement of the neck veins, facial suffusion, and a
positive Pemberton's sign. The patient's medical history included
long-standing arteriosclerosis, a pulmonary embolism diagnosed 2 years before
this presentation, and triple-vessel coronary artery bypass grafting for
coronary artery disease performed 7 years before this presentation. The
coronary artery bypass surgery had been an uncomplicated procedure, and the
patient had been free of symptoms of coronary disease in the interim.
The patient had recently undergone multiple diagnostic evaluations for
investigation of lethargy and weight loss that had included CT of the thorax
and abdomen. This examination had failed to reveal any cause for the symptoms.
When the patient presented with signs and symptoms of superior vena cava
obstruction, the previously obtained CT scan was reviewed to see whether a
potential cause could be found. A pseudoaneurysm of the right coronary artery
bypass vein graft was identified (Fig.
1A). This dilated vascular structure was deemed a pseudoaneurysm
because of its proximity to the anastomosis of the vein graft and the right
coronary artery. This finding had not been noted at the time of the previous
examination.
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Fig. 1A. —55-year-old man with lethargy, weight loss, and clinical
signs of acute superior vena cava obstruction. Patient had undergone
triple-vessel coronary artery bypass grafting for coronary artery disease 7
years earlier. Initially obtained axial CT scan shows pseudoaneurysm
(arrow) of right coronary artery bypass vein graft. This finding had
initially been missed. Note pacing wires in situ within superior vena
cava.
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A repeat CT scan of the thorax showed a large ruptured pseudoaneurysm of
the right coronary artery bypass vein graft with a hematoma that was
compressing the right atrium and superior vena cava
(Fig. 1B). Although an arterial
phase CT scan was acquired, the ruptured pseudoaneurysm was more clearly
defined on the delayed phase scan (Fig.
1C). The findings were consistent with the rupture of a
pseudoaneurysm of the coronary artery bypass vein graft, resulting in acute
superior vena cava obstruction. The patient developed a fatal arrhythmia while
being transferred to the operating room for surgical repair, and subsequent
resuscitation attempts were unsuccessful.
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Fig. 1B. —55-year-old man with lethargy, weight loss, and clinical
signs of acute superior vena cava obstruction. Patient had undergone
triple-vessel coronary artery bypass grafting for coronary artery disease 7
years earlier. Axial CT scan obtained 6 weeks after A at same level
shows ruptured pseudoaneurysm of right coronary artery bypass vein graft. Note
displacement of pacing wires to left and complete obliteration of superior
vena cava lumen. Mediastinal hematoma is also seen.
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Fig. 1C. —55-year-old man with lethargy, weight loss, and clinical
signs of acute superior vena cava obstruction. Patient had undergone
triple-vessel coronary artery bypass grafting for coronary artery disease 7
years earlier. Axial delayed phase CT scan obtained 6 weeks after A at
lower level shows large ruptured pseudoaneurysm compressing right
ventricle.
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Discussion
Obstruction of the superior vena cava is a relatively common medical
emergency usually seen as a complication of lung cancer or lymphoma
[1,
3]. Early diagnosis and
appropriate intervention are required to prevent airway obstruction, to
alleviate cerebral venous hypertension, and to treat symptoms secondary to
mediastinal compression. Coronary artery bypass vein graft pseudoaneurysms are
unusual complications of coronary artery bypass surgery, usually occurring
several years after the initial procedure
[2].
Previously described presentations of saphenous vein graft aneurysms
include compression of the right atrium
[4], non-Q-wave myocardial
infarction [5], and development
of a fistula between the graft and the right atrium
[6]. Superior vena cava
obstruction has been reported as a complication of a rupture of a coronary
artery bypass vein graft [7].
To our knowledge, ours is the first case in which the CT findings have been
described. Early diagnosis of a pseudoaneurysm in a coronary artery bypass
vein graft allows expedient endovascular or surgical repair. In the case
presented, the diagnosis was missed on the CT scan obtained 6 weeks before the
acute presentation. We therefore suggest that the heart and mediastinal
structures should be carefully reviewed in any patient with a history of
coronary artery bypass surgery to avoid this potentially correctable,
uncommon, but lethal complication.
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Introduction
Case Report
