Page 28 - Journal of Structural Heart Disease Volume 5, Issue 2

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Case Report
good position. Following the closure of the fistula, the Fontan circuit pressure decreased from 25 mm Hg to 20 mm Hg of mean pressure.
The patient was extubated in catheterization lab and transferred back to the intensive care unit. Over the next couple of days, the patient improved and both chest tubes were removed. TTE prior to dis- charge showed a small shunt at the site of the fistula, but overall improved. Patient was discharged home with cardiology follow-up and twice daily Furose- mide with plan to wean the medication over the next few weeks. Outpatient cardiology follow-up showed consistent improvement.
Discussion
Aortopulmonary artery fistula is a rare type of anom- alous vascular communication. This unusual commu- nication, reportedly, has been associated to aortic aneurysm or has appeared as a complication of aortic aneurysm rupturing into the pulmonary artery [2].
There are two types of APF: congenital and ac- quired. Congenital AFP are extremely rare but have been described in case reports in which patients also had an associated coronary artery fistula. The patho- genesis is not very well understood. [1]
Our case likely represents a case of acquired APF given that this is a patient with history of complex congenital heart disease who had multiple echocar- diographic evaluations and catheterizations in the past not revealing the anomalous communication. However, the etiology is still not clear. It has been shown that aortopulmonary collateral vessels occur with the overall prevalence of 36% in the population of patients who have undergone bidirectional Glenn or Fontan procedure [7] , a category under which our patient falls.
Acquired APF in the pediatric and adult popula- tions are shown to be associated with some level of defect in the wall of the great vessels including an intimal tear, pseudoaneurysm or aneurysm break- ing into the pulmonary artery and resulting in direct communication between these great vessels [3, 4]. In pediatric populations, there have been multiple re- ports of iatrogenic APF formations after pulmonary angioplasty using different devices for percutane- ous closure [8, 9]. In all cases, a mild intimal tear in
the pulmonary artery or its branches was revealed using magnetic resonance imaging (MRI). Trauma is a significant risk factor for the development of mild to severe injuries of the vessel wall that can lead to fistu- la formation [4, 5]. Most vessel wall injuries, even mi- nor ones, would likely be seen on MRI which was not done in this case. However, it is reasonable to say that his bicycle accident could have predisposed him to developing a minor tear in the wall of his great vessel. Although our patient did have a fall prior to presenta- tion, his symptoms date back prior to the fall, there- fore the etiology of his condition remains uncertain.
APF leads to significant left-to-right shunt and places a hemodynamic burden on the heart and lungs. Clinical presentation is consistent with variable level of congestive heart failure depending on the di- ameter of the anomalous vessel as well as the predis- posing factors such as trauma. In case of significant left-to-right shunting from aorta to pulmonary artery, as described in our patient with APF where blood was shunted from aorta where systolic pressure was 90 mmHg to a much lower pressure in pulmonary artery leading to increased Fontan circuit pressures to 25 mm Hg and overcirculation of the pulmonary vascular bed with consequent dyspnea, pleural effu- sions and pulmonary edema. Additionally, increased Fontan circuit pressure leads to liver congestion, ascites and abdominal symptoms. In patients with Fontan palliation, in order for the circuit to function properly, low circuit pressures must be maintained. The increase in Fontan circuit pressure to 25 mm Hg in our patient contributed significantly to liver con- gestion and to ascites formation further on. It is well known that high venous pressures can compromise lymphatic circulation as well. Additionally, the exten- sion of Glisson’s capsule can also lead to right upper quadrant abdominal pain that our patient initially presented with.
The treatment of APF includes surgical repair or percutaneous closure of the anomalous vessel using different types of devices. Surgical treatment is the treatment of choice in the case of aortic pseudoan- eurysm or aneurysm rupturing into the pulmonary artery and in case of severe trauma leading to the communication of the great vessels. Percutaneous embolization has become the treatment of choice for the occlusion of anomalous arteriovenous and
Dzelebdzic S. et al.
Fontan Failure