Ann Thorac Surg 2003;76:929-931
© 2003 The Society of Thoracic Surgeons
Case report
Aorto-right atrial fistula
Ahmed F. Elwatidy, MD, FRCSa*,
Ahmed N. Galal, MDa,
David Rhydderch, FRCAa,
Abdullah K. Ashmeg, FRCSa
a King Fahd Armed Forces Hospital, Cardiac Services Department, Jeddah, Saudi Arabia
Accepted for publication February 14, 2003.
* Address reprint requests to Dr Elwatidy, King Fahd Armed Forces Hospital, P.O. Box 9862, Jeddah 21159, Saudi Arabia
e-mail: afelwatidy{at}hotmail.com
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Abstract
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We report a child in whom a fistula connected the descending thoracic aorta to the right atrium. This is a previously unreported cardiac malformation. The patient was initially misdiagnosed as having a patent ductus arteriosus (PDA). On clinical examination and auscultation, the problem was different from PDA in that the continuous machinery murmur was better heard on the right parasternal area and posteriorly on the left. Surgical ligation of the fistula through a left thoracotomy abolished the murmur.
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Introduction
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Congenital fistula between the aorta and right or left atria is a rare congenital anomaly of the heart. Aortico-right atrial fistula, in particular, represents a dilemma of differentiation from a coronary-cameral fistula that abnormally communicates one of the major coronary arteries to one of the cardiac chambers. Echocardiography and cardiac catheterization are helpful in establishing the diagnosis.
A 3-year-old girl was referred to us as a case of patent ductus arteriosus (PDA) due to the presence of a continuous machinery murmur over the precordium. On examination she was well looking, not in distress, and not pale or cyanotic. Her body weight was 15.5 kg, height 101 cm, and vital signs were normal. Head and neck examination was normal, the chest was clear, and cardiac examination revealed a muffled first and second heart sound with continuous machinery murmur grade 3/6 that was maximally heard over the right parasternal area and posteriorly on the left side. An electrocardiogram showed right axis deviation. Chest roentgenogram showed mild cardiac enlargement, with bilateral hilar congestion. Echocardiography showed situs solitus with atrioventricular and ventriculoarterial concordance. The atrial septum was intact with normal pulmonary venous drainage. We noted an abnormal, continuous, high velocity flow into the right atrium (RA), which was dilated, with a gradient of 91 mm Hg. Both right and left ventricles were dilated with good function, intact ventricular septum, normal aortic and pulmonic valves, and normal aortic arch with no aortic coarctation or PDA. A long abnormal tortuous channel started from the aortic isthmus and ran inferior to the right pulmonary artery, opening into a wider chamber, which opened into the RA.
In view of these rare echocardiographic findings, cardiac catheterization was done to confirm the diagnosis and possibly attempt closure of the fistula. Right and left heart catheterization were done and confirmed the diagnosis of the fistula, which originated from the descending thoracic aorta close to the origin of the PDA and coursed parallel to the right pulmonary artery behind the ascending aorta (Figs 1 and 2).
The fistula ended in a sac behind the junction of the superior vena cava
with the RA, which opened into the RA with a small orifice. The shunt ratio (QP:QS) was 3:1. The findings were not attractive for device closure as the fistula had a wide neck and caliber throughout the entire course; therefore, the decision was in favor of surgical closure.
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Fig 1. Left anterior oblique view showing the course of the fistula from the isthmus of the aorta to the right atrium. (RA = right atrium; RV = right ventricle.)
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Under general anesthesia, arterial and central venous lines were inserted and the patient was positioned on her right side. A small left posterolateral thoracotomy was performed, and the left pleura was opened. The mediastinal pleura was dissected and retracted with some stitches. The distal aortic arch was also dissected down to the proximal descending thoracic aorta. The ligamentum arteriosum was divided between two ligatures. The fistula was wide (7 to 9 mm) at the origin from the right side of the descending thoracic aorta and posteriorly between the origin of left subclavian artery and ligamentum arteriosum, taking a sigmoid course after the origin, and then passing straight into the pericardium close to the left pulmonary artery.
A strong "thrill" was palpated over the fistula. The fistula was dissected down to the pericardial reflection, and divided between two ligatures. The thrill disappeared completely. The mediastinal pleura was closed, one chest drain was inserted, and the chest was closed. A thoracic epidural catheter was inserted for postoperative pain management, the child was extubated in the operating room, and sent to the intensive care unit in a stable condition. The postoperative course was smooth, the machinery murmur disappeared, chest roentgenogram showed a reduction in cardiac size, and postoperative echocardiography showed complete disappearance of the fistula. The child was discharged home on the third postoperative day in good condition.
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Comment
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Arteriovenous fistulas of the heart are relatively rare but may involve one of the coronary arteries, an intercostal artery, or an internal mammary artery. They may be associated with continuous machinery murmurs similar to those occurring in PDA, which is typically more superficial, and sound extracardiac in origin. Some of these fistulas may communicate the aorta to the right or left atrium [1, 2]. Rosenberg and colleagues [3] reported four cases of an unusual form of aortico-right atrial communication; all cases were asymptomatic but had atypical continuous murmur on examination. A distinctive appearance was noted on the angiograms, with a large tortuous tunnel noted superior to the left sinus of Valsalva, passing posterior to the aortic root beforeterminating near the right atrial-superior vena caval junction. These fistulas were readily identified by two-dimensional echocardiography and three of them were closed surgically. Another case of fistulous tract between the aorta and RA was reported by Danilowicz and associates [4] in a newborn who presented in heart failure. The fistula was between the right sinus of Valsalva and the RA and the child had congestive heart failure in the first day of life with failed medical treatment; surgical repair at 5 days of age was successful. Preoperative echocardiographic evaluation diagnosed the defect and after the operation confirmed a complete repair. In the previous two reports, the description of the fistulas was different from our case in that they all originated from the ascending aorta; however, echocardiographic diagnosis and surgical repair were standard procedures in almost all of them. Soler and associates [5] also reported an unusual case of congenital arteriovenous fistula arising from the descending aorta and draining separately into the superior vena cava, the azygos vein, and the innominate vein. Clinically, the case simulated a PDA.
Another child with congenital fistula between the descending thoracic aorta and the left atrium was reported by Nihoyannopoulos and colleagues [6]. The fistula was surgically ligated as well.
The patho-embryologic genesis of this type of fistulas is not clear. However, an abnormality in the sixth aortic arch "arterial component" or sinus venosus or cardinal veins "venous component" could have contributed to the formation of such fistula.
As in the other cases of arteriovenous fistulas reported before, the diagnosis was made by echocardiography, although cardiac catheterization was useful in confirming the diagnosis. We believed that closure of the fistula was warranted as this was essentially a significant left to right shunt with Qp/Qs of 3:1, which would, over time, lead to unwanted effects.
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References
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- Brook M.M., Heyman M.A. Arterial abnormalities. In: Emmanouilides G.C., Riemenschneider T.A., Allen H.D., Gutgesell H.P., eds. Moss and Adams heart diseases in infants, children and adolescents. Baltimore, MD: Williams and Wilkins, 1995:965-966.
- Coto E.O., Caffarena J.M., Such M., Marques J.L. Aorto-right atrial communication. Report of an unusual case. J Thorac Cardiovasc Surg 1980;80:941-944.[Abstract]
- Rosenberg H., Williams W.G., Trusler G.A., et al. Congenital aortic-right atrial communications. The dilemma of differentiation from coronary-cameral fistula. J Thorac Cardiovasc Surg 1986;91:841-847.[Abstract]
- Danilowicz D., Presti S., Colvin S., Rutkowski M. Congenital fistulous tract between aorta and right atrium presenting as heart failure in a newborn. Pediatr Cardiol 1989;10:93-97.[Medline]
- Soler P., Mehta A.V., Garcia O.L., 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]
- Nihoyannopoulos P., Sapaford R., Oakley C.M. Congenital fistula between the aorta and left atrium. Br Heart J 1987;57:387-390.[Abstract/Free Full Text]
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Abstract
Introduction
