Aorta-right atrial tunnel

Abstract

Aorta-right atrial tunnel is a vascular channel that originates from one of the sinuses of Valsalva and terminates in either the superior vena cava or the right atrium. The tunnel is classified as anterior or posterior, depending upon its course in relation to the ascending aorta. An origin above the sinotubular ridge differentiates the tunnel from an aneurysm of the sinus of Valsalva, and the absence of myocardial branches differentiates it from a coronary-cameral fistula. Clinical presentation ranges from an asymptomatic precordial murmur to congestive heart failure. The embryologic background and pathogenesis of this lesion are attributable either to an aneurysmal dilation of the sinus nodal artery or to a congenital weakness of the aortic media. In either circumstance, progressive enlargement of the tunnel and ultimate rupture into the low-pressure right atrium could occur under the influence of the systemic pressure.The lesion is diagnosed by use of 2-dimensional echocardiography and cardiac catheterization. Computed tomographic angiography is an additional noninvasive diagnostic tool. The possibility of complications necessitates early therapy, even in asymptomatic patients or those with a hemodynamically insignificant shunt. Available treatments are catheter-based intervention, external ligation under controlled hypotension, or surgical closure with the patient under cardiopulmonary bypass.Herein, we discuss the cases of 2 patients who had this unusual anomaly. We highlight the outcome on follow-up imaging (patient 1) and the identification and safe reimplantation of the coronary artery (patient 2).

Keywords: Aorta/abnormalities/surgery; coronary vessel anomalies/classification/diagnosis; diagnosis, differential; heart atria/abnormalities/surgery; sinus of Valsalva; tomography, X-ray computed; treatment outcome; vena cava, superior/abnormalities.

Fig. 1 Patient 1. Aortic root injection. Angiography A) in right anterior oblique view and A, inset) computed tomography (CT) show the tunnel's origin (arrowhead) and termination (arrow). B) A CT angiographic reconstruction shows the close relationship between the tunnel and the left main coronary artery (arrowhead) in the left aortic sinus, the tunnel's retroaortic course, and its termination (arrow). C) Postoperative CT angiographic images after 3 months (left) and 18 months (right) show progressive obliteration of the tunnel (asterisks) and remodeling of the aortic root (arrows). * = tunnel; Ao = aorta; LA = left atrium; LAD = left anterior descending coronary artery; LCS = left coronary sinus; OMB = obtuse marginal branch; PA = main pulmonary artery; RA = right atrium; RPA = right pulmonary artery; SVC = superior vena cava

Fig. 2 Patient 2. Computed tomographic angiograms show A) the origin (R), course (*), and termination (Tn) of the tunnel, and B) the course of the tunnel (*) and the origin of the right coronary artery (arrow) (sagittal view). C) Intraoperative photograph. Inset shows the right coronary artery (arrow). * = tunnel; Ao = aorta; LA = left atrium; LV = left ventricle; R = right aortic sinus; RA = right atrium; Tn = distal aneurysmal segment of the tunnel