Congenital arteriovenous fistula between descending aorta and the left innominate vein

Continuous Murmur in a Child: Sometimes It Is a Zebra

“…During development, venous blood with aortic origin above the third or fourth intercostal arteries drains into the left innominate vein and venous blood below these arteries drains into the azygos or hemiazygos veins. 1 , 3 The abnormal vessel in our case originated from the level of T7-T8 and ultimately connected to the left innominate vein. Although there was an additional connection to the azygos vein, it is abnormal embryologically for a vessel originating below the fourth intercostal space to ultimately connect with the left innominate vein, and such a situation has been described only once previously.…”

“…The differential diagnosis for a continuous murmur that radiates to the back includes patent ductus arteriosus, aortopulmonary window, arteriovenous or coronary fistula, ruptured sinus of Valsalva, and mammary souffle. 1 , 2…”

“…Thoracic AVF are either acquired—secondary to trauma or ruptured dissection or in patients with connective tissue disorders—or congenital. 1 Congenital causes are rare and result from abnormalities in embryonic development. During development, venous blood with aortic origin above the third or fourth intercostal arteries drains into the left innominate vein and venous blood below these arteries drains into the azygos or hemiazygos veins.…”

“…Although there was an additional connection to the azygos vein, it is abnormal embryologically for a vessel originating below the fourth intercostal space to ultimately connect with the left innominate vein, and such a situation has been described only once previously. 1 …”

“…A review of current case reports for congenital systemic AVF demonstrates that most are intervened upon, either surgically or via cardiac catheterization, although more commonly when patients present with symptoms of congestive heart failure. 1 , 5 , 6 , 9 In discussion with the family, it was determined that the risk associated with catheter-based interventions outweighed the benefit in an asymptomatic healthy child. As a result, our patient was managed conservatively with no intervention and yearly TTE to assess chamber sizes as sequelae of a significant shunt.…”