Infective endocarditis of an asymptomatic congenital aorta-right atrial tunnel: a case report

Abstract

Background: Aorta-right atrial tunnel (ARAT) is a rare congenital anomaly whose aetiology and incidence are unknown. It might represent a diagnostic and therapeutic challenge requiring a combination of imaging modalities and an integrated teamwork.

Case summary: We report a case of a 23-year-old man with an asymptomatic ARAT complicated by infective endocarditis, diagnosed with non-invasive multimodality imaging, and successfully treated with a catheter-based approach.

Discussion: Aorta-right atrial tunnel closure in asymptomatic patients is still a matter of debate. Considering the risk of serious complications surgical treatment might be recommended soon after diagnosis. In selected cases, catheter-based closure might represent a safe, effective, and less invasive alternative to traditional surgical approach.

Keywords: Aorto-right atrial tunnel; Coronary vessel anomalie; Endocarditis; Multidetector computed tomography angiography; Transcatheter closure; Transoesophageal echocardiography.

Figure 1

(A) (a) Transoesophageal echocardiography showed right atrial dilation and bacterial vegetations (orange arrows) inside the tunnel-like structure; (b) two-dimensional colour multiplanar reconstruction images showing high-velocity flow within the tunnel (white arrowhead) originating from the right coronary sinus and running parallel to the right coronary artery (red arrow). (B) Chest computed tomography scans (A, axial plane; B–D, coronal planes) showing multiple pseudo-nodular cavitations (yellow arrows) and bilateral pneumonia, hilar adenopathy, and pronounced right atrial profile. Ao, aorta; CT, computed tomography; MPR, multiplanar reconstruction; RA, right atrium; RCA: right coronary artery.

Figure 2

Three-dimensional multidetector computed tomography angiography pre-operative assessment. (A and B) Volume-rendering three-dimensional reconstruction showing the aorta-right atrial tunnel (red arrows) arising from the right aortic sinus and emptying into the right atrium. Note the coronary side branch (white arrows) originating from the proximal right coronary artery. (C) Curved multiplanar reconstruction showing the entire path of the aorta-right atrial tunnel. (D) Maximum intensity projection reconstruction confirming the origin of the side branch (black arrow) from the proximal right coronary artery. 3D-MDCTA, three-dimensional multidetector computed tomography angiography; ARAT, aorta-right atrial tunnel; RCA, right coronary artery.

Figure 3

Procedural steps of the catheter-based aorta-right atrial tunnel closure. (A and B) Aortic angiography showing the aorta-right atrial tunnel (white arrow) originating from the right coronary sinus and draining into the right atrium. (C) Advancement from the inferior vena cava of a 7-Fr long sheath over the artero-venous loop towards the ascending aorta. (D) Opening of the distal disc of the closure device (black arrow). (E) Control angiography before full device deployment. (F) Occlusion device correctly positioned inside the aorta-right atrial tunnel (white arrowhead). ARAT, aorta-right atrial tunnel; RA: right atrium.

Figure 4

Transoesophageal echocardiography colour Doppler 3 months after the procedure. (A) Correct device position (white arrow). Note that the distal disc of the device is not protruding into the aorta. (B) Xplane transoesophageal echocardiography showing mild residual left-to-right shunt (orange arrows). White arrows indicate occlusion device position inside the tunnel. (C) Continuous-wave Doppler ultrasound showing early diastole flow with peak velocity of 80 cm/s inside the tunnel. Ao, aorta; CW, continuous-wave; RA, right atrium; TOE, transoesophageal echocardiography.

Figure 5

Three-dimensional multidetector computed tomography angiography at 6-month follow-up. (A–C) Volume rendering three-dimensional reconstructions showing correct position of the occlusion device (orange arrows) inside the aorta-right atrial tunnel. (D and E) Curved multiplanar reconstructions showing an almost complete occlusion of the aorta-right atrial tunnel. Note the hypodense region (stars) inside the occluder device visible in the longitudinal (D) and cross-section views (E) indicating neo-intimal growth. 3D-MDCTA, three-dimensional multidetector computed tomography angiography; ARAT, aorta-right atrial tunnel.