AJR 2001; 176:550-551
© American Roentgen Ray Society
Regression of Arteriovenous Fistula Between the Descending Aorta and Azygos Vein After Catheterization
Natsuko Saito,
Hitoshi Horigome,
Junko Shiono and
Yukihisa Saida
University of Tsukuba Tsukuba 305-8575, Japan
A 16-month-old boy was referred to our hospital for evaluation of a
continuous murmur heard over the middle area of the back. The child appeared
healthy, and physical examination revealed negative findings except for the
audible murmur on auscultation. A radiograph of the chest showed a normal
cardiac silhouette and normal pulmonary vasculature. Echocardiography showed
no abnormal findings. CT scans of the chest showed an abnormal vessel that ran
along the right border of the vertebral column and drained into the azygos
vein (Fig. 3A), but the route
of the arteriovenous fistula could not be exactly determined. Abdominal
sonography also failed to determine the route in detail. Angiography of the
descending aorta showed an abnormal vessel originating from the descending
aorta just below the diaphragm (Fig.
3B). We inserted a 4-French end-hole catheter into the abnormal
vessel and injected 5 mL of ioxalic acid (Hexabrix 320; Eiken Chemical, Tokyo,
Japan), an ionic iodinated contrast medium. The additional selective
angiography of the abnormal vessel showed that the artery ran to the right
side posteriorly and drained into the superior vena cava through the azygos
vein, constituting a left-to-right shunt
(Fig. 3C). The calculated ratio
of the pulmonary blood flow to systemic flow was 1.0. Immediate intervention
to close the fistula, such as embolization, was not indicated.
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Fig. 3A. —16-month-old boy with arteriovenous fistula between
descending aorta and azygos vein. CT scan of chest shows abnormal vessel
(arrow) that runs along right border of vertebral column and drains
into azygos vein.
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Fig. 3B. —16-month-old boy with arteriovenous fistula between
descending aorta and azygos vein. Initial angiogram of descending aorta
(anteroposterior image) reveals that feeding artery arises from descending
aorta just below diaphragm and drains into superior vena cava through azygos
vein (arrow).
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Fig. 3C. —16-month-old boy with arteriovenous fistula between
descending aorta and azygos vein. Selective angiogram of arteriovenous fistula
(lateral image) shows that feeding artery and draining vein are both single,
and ostium of fistula is slightly stenotic.
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When the child visited our outpatient clinic 2 weeks after the diagnostic
catheterization, the murmur appeared to have decreased in intensity. During a
follow-up visit 2 months later, the murmur was not audible on auscultation.
Follow-up angiography performed 6 months after the first angiography revealed
complete regression of the fistula (Fig.
3D).
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Fig. 3D. —16-month-old boy with arteriovenous fistula between
descending aorta and azygos vein. Follow-up angiogram of descending aorta
(anteroposterior image) shows no detectable abnormal vessels.
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A congenital systemic arteriovenous fistula between the descending aorta
and azygos or hemiazygos vein is extremely rare. To our knowledge, there are
only four reported cases of the same type of fistula
[1,2,3].
However, spontaneous regression of the lesion or regression without
intervention has not been reported in the thoracic area. Few reports have
shown this phenomenon in cerebral arteriovenous malformation. Abdulrauf et al.
[4] reported that spontaneous
closure occurred in 0.9% of patients. They also reviewed previously published
reports and proposed several factors that might cause this rare phenomenon.
These include hemorrhage around the lesion with subsequent mass effect,
leading to reduced blood flow and thrombosis; elongation of abnormal vessels;
turbulence of blood flow; changes in the vessel wall; and presence of a single
feeding artery and a draining vein. In our patient, closure of the fistula was
probably caused by one or more of the following conditions: presence of a
stenotic ostium of the feeding artery, which resulted in turbulent blood flow
and continuous murmur; presence of single feeding artery and draining vein;
injury to the endothelium by the tip of the angiographic catheter with
subsequent clot formation in the feeding vessel; and acute venous thrombosis
induced by the contrast medium. Although the exact mechanism of arteriovenous
fistula regression in our patient could not be specified, one should be aware
of possible regression, particularly when the intensity of the murmur
diminishes after angiographic catheterization.
References
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Sutton D, North EA. Unusual arteriovenous communications presenting
as cardiac murmurs in infancy: report of three cases. Br J
Radiol 1977;50:871
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Soler P, Mehta AV, Garcia OL, Kaiser G, Tamer D. Congenital
systemic arteriovenous fistula between the descending aorta, azygos vein, and
superior vena cava. Chest
1981;80:647
-649[Abstract/Free Full Text]
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Gamba PG, Longo M, Zanon GF, Guglielmi M. Arteriovenous fistula
between descending aorta and hemiazygos vein. Eur J Pediatr
Surg 1991;1:49
-50
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Abdulrauf SI, Malik GM, Awad IA. Spontaneous angiographic
obliteration of cerebral arteriovenous malformations.
Neurosurgery
1999;44:287
-288
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