DISCUSSION
The Congenital Aorto-Right Ventricle Fistula is a defect on the wall of the aorta and, although there is no definitive etiology for this anomaly, it is probably caused by its weakness throughout the development. The abnormalities of the Sinus of Valsalva are characterized into three different groups: (1) unruptured aneurysm of the Sinus of Valsalva, (2) aneurysm of the Sinus of Valsalva with intracardiac or extracardiac rupture, and (3) intracardiac or extracardiac fistula of the Sinus of Valsalva[1,5].
Meyer and colleagues[1] made a survey about the procedures realized at the Texas Heart institute from April, 1956, to September, 1973. They found 45 patients with aneurysm and/or fistula of the Sinus of Valsalva, representing 0.43% of all procedures which were required cardiopulmonary bypass. Of the 45 patients in the group, 22 had an unruptured aneurysm, whereas 10 and 13 had a ruptured aneurysm and a simple fistulous communication, respectively. On the other hand, according to Walpot and contributors[6] and Nishi et al.[5], the major cause of an aorto-cardiac fistula is a rupture of an aortic sinus aneurysm, accounting for 76% of the cases.
Many patients can be asymptomatic, but the typical symptoms are like Congestive Heart Failure (CHF). A pain in the chest and a sudden onset of the symptoms point to a ruptured aneurysm. It is possible to hear a “to-and-fro” murmur on cardiac auscultation with a systolic and diastolic thrill. The diagnosis is usually taken by transthoracic or transesophageal echocardiography, cardiac catheterization with aortography, computed tomography or magnetic resonance imaging (MRI), revealing a left-to-right shunt.
It is important to differentiate the ARVF from the Aorto-Right Ventricular Tunnel (ARVT). This condition, as the first, communicates the aorta to the right ventricle, however the second one’s perforation arises above the sinutubular junction instead. In the ARVF, the communication is localized below the sinutubular structure.[8] Most part of the aorto-ventricle tunnel communicates the aorta to the left ventricle (90%), and just a small part of the cases do to the right ventricle[9].
The surgical correction is the treatment of choice. If promptly diagnosed and treated, it is possible to avoid major morbidity resulting from CHF caused by left-to-right shunt[2]. Even in asymptomatic patients, closure of the fistula is recommended in low surgical risk person due to the low rate of procedure complications and the risk of heart failure, bacterial endocarditis, pulmonary vascular disease, aneurysm formation and spontaneous rupture[3]. Currently, an alternative of treatment is transcatheter closure, but it is required more studies to analyze the optimal management[2,5].