Transcatheter Coil Occlusion of a Thoracic Arteriovenous Fistula in an Infant with Congestive Heart Failure

Abstract

An 8-week-old baby boy presented at our institution with a continuous murmur and congestive heart failure. Echocardiography showed normal cardiac anatomy. Catheterization revealed the presence of a large thoracic arteriovenous fistula between the descending thoracic aorta and the hemiazygous system, with eventual drainage into the azygous vein and the innominate vein. Coil occlusion was performed successfully with a Gianturco coil.

Arteriovenous fistulas can occur between any arterial or venous structure. ^1–6 When these communications are in the thorax, they generally result in a continuous murmur and are often confused with a patent ductus arteriosus. Transcatheter occlusion of congenital vascular malformations with a variety of occluding devices has been well described in both the pediatric and adult literature. ^7–11

We describe the case of an 8-week-old baby boy with a large thoracic arteriovenous fistula between the descending thoracic aorta and the hemiazygous system (with eventual drainage into the both the azygous and innominate veins). The fistula was closed successfully in the cardiac catheterization laboratory with use of a small vascular sheath and a single Gianturco coil.

Case Report

An 8-week-old infant had first presented at the emergency room at 4 weeks of age with bronchiolitis. A heart murmur was heard during the initial examination, and a cardiologist was consulted. Physical examination confirmed the presence of a grade 2/6 continuous murmur heard best over the anterior precordium and the left upper sternal border. A clinical diagnosis of patent ductus arteriosus was made and a 2-week follow-up office visit was arranged. During the office visit, a history of intermittent tachypnea was elicited. Chest radiography indicated borderline cardiomegaly with normal pulmonary vascularity. Echocardiography showed normal intracardiac anatomy but failed to reveal a patent ductus arteriosus. A presumptive diagnosis of arteriovenous fistula was made but could not be confirmed echocardiographically.

The child was sent home, and the parents were instructed to return if signs and symptoms of congestive heart failure appeared. Two weeks later, the child was brought back because of increasing respiratory rate and poor oral intake. In addition to the continuous murmur, the physical examination revealed hepatomegaly (liver 2 cm below the right costal margin). Chest radiography showed cardiomegaly and increased pulmonary vascularity. The infant was admitted to the hospital, was started on both digoxin and diuretic therapy, and was scheduled for cardiac catheterization the following day (10 February 1999).

At cardiac catheterization, the right-heart pressures were normal. The arterial pressure measurements indicated wide pulse pressure. There was a step-up in oxygen saturation levels between the high superior vena cava (76%) and the left innominate vein (84%), low superior vena cava (87%), and pulmonary artery (83%). The calculated Qp:Qs was 1.5. Prior to left heart catheterization, the patient received a 50-U/kg bolus of heparin. Angiography performed in the descending thoracic aorta revealed a large thoracic arteriovenous fistula between the descending thoracic aorta and the hemiazygous system, with eventual drainage into the azygous vein and the innominate vein (Fig. 1).

Fig. 1 Angiogram of the descending aorta showing a left-sided aortic arch with a large thoracic arteriovenous fistula (white arrow) arising posterior and to the left of the descending thoracic aorta. There is faint opacification of the enlarged superior portion of the hemiazygous vein (black arrow) as it courses toward the innominate vein.

Selective angiography of the fistula was performed to delineate the vascular course and venous drainage (Fig. 2). The fistula measured between 3.6 and 4.1 mm near its origin from the descending thoracic aorta (Fig. 1). The fistula coursed posteriorly into the hemiazygous system before draining into both the azygous vein and the left innominate vein. There was a region of stenosis at its insertion site into the left innominate vein. There were several diffuse branches connecting the fistula with the hemiazygous system, paravertebral veins, azygous vein, and superior vena cava (Fig. 2).

Fig. 2 Selective angiogram of the large systemic arteriovenous fistula showing venous drainage into the left innominate vein (white arrow), azygous vein (black arrow), and superior vena cava.

After review of the available data, we decided to proceed with coil occlusion of the large arteriovenous fistula. A 4-F Performa® Berenstein catheter (Merit Medical; Angleton, Tex) was advanced from the left femoral artery and, together with a Magic Torque™ guidewire (Meditech; Watertown, Mass), was used to cannulate the fistula. Hand injection of contrast material was performed to confirm proper placement of the catheter within the fistula. The marks of an NIH Cardiomarker catheter (Medtronic Vascular; Danvers, Mass) were used to measure the vessel. The size of the coil was determined according to previously described methods. ^9,12 A single Gianturco coil (0.038-inch, 8-cm × 6-mm; Cook Inc.; Bloomington, Ind) was used to occlude the fistula as close as possible to its origin from the descending aorta. Angiography of the descending aorta after coil occlusion confirmed proper coil placement and complete occlusion of the fistula (Fig. 3). Repeat oxygen saturation measurements were then obtained in the left innominate vein, superior vena cava, and pulmonary artery. There was no step-up in saturation measurements and the Qp:Qs was 1. Physical examination after coil occlusion indicated no residual heart murmur. Chest radiography performed the following day showed normal heart size and normal pulmonary vascularity. At the 1-year follow-up, the child was asymptomatic and doing well.

Fig. 3 Angiogram of the ascending aorta after coil occlusion showing complete occlusion of the large systemic arteriovenous fistula. The Gianturco coil (white arrow) is seen in good position within the proximal arteriovenous fistula.

Discussion

Congenital thoracic arteriovenous fistulas, although rare, have been described. ^3–6 When situated in the thorax, these lesions are usually accompanied by a continuous murmur. They occasionally present as diagnostic problems and can be confused with more common cardiac or extracardiac abnormalities, such as patent ductus arteriosus, as was the case in our patient.

As previously reported by Soler and colleagues, ³ a congenital systemic arteriovenous fistula arising from the descending aorta and draining into the innominate vein, azygous vein, and superior vena cava is rare. Those authors postulated that this particular type of malformation could be attributed to abnormal fistulous communications between embryologic arterial and venous channels that were originally normal. ³

The signs and symptoms associated with the presence of an arteriovenous fistula vary in relation to the size of the fistulous communication and the degree of left-to-right shunting produced. If the shunt is small, most patients remain asymptomatic. However, if the fistula is large and there is a moderate-to-large left-to-right shunt, as in our patient, early and more pronounced hemodynamic effects occur.

In the past, surgery was the recommended therapy for arteriovenous fistulas. With the introduction of transcatheter interventions, however, balloon occlusion, coiling, and other occlusion devices have come to the forefront of therapy. Both the Gianturco coil, and more recently, the Gianturco-Grifka Vascular Occlusion Device (Cook Inc.) have been used to close arteriovenous malformations. ^7–9,11 In the current case, because of the young age and small size of the infant, the decision was made to occlude the arteriovenous fistula with a Gianturco coil. The Gianturco coil has the advantage of being deployable through a small 4-F sheath, which limits the risk of injury to the femoral artery. The Gianturco-Grifka Vascular Occlusion device is delivered through an 8-F sheath and is ideally suited for larger children.

In conclusion, thoracic arteriovenous fistulas between the descending aorta and the hemiazygous system with eventual drainage into the azygous vein and innominate vein are rare. We describe what to our knowledge is the 1st documented coil occlusion of this rare type of arteriovenous fistula in an 8-week-old infant who was in congestive heart failure. A small 4-F catheter was used to deliver the Gianturco coil into the large fistula. The fistula was occluded as close to the origin of the vessel from the descending aorta as possible; at the same time, we made sure that all the loops of coil were delivered safely into the vessel. With use of the small 4-F sheath and coil delivery catheter, flow to the leg was preserved without arterial compromise. In our opinion, transcatheter coil embolization therapy is safe and should be considered as a treatment option for patients who have moderate-to-large systemic arteriovenous fistulas.