A rare case of endocarditis vegetation in the right atrium related to an aortic-atrial fistula

A 45-year-old man without any cardiovascular risk factor or relevant past medical history was admitted to the emergency room with fever and aphasia. Cerebral magnetic resonance and computed tomography (CT) documented acute cerebral ischaemia, and the blood cultures detected Aerococcus urinae. Transthoracic and transoesophageal echocardiography were performed and found: (i) a tricuspid aortic valve (AV) with large endocarditis vegetations involving all the cusps with severe aortic regurgitation, (ii) an abscess surrounding the non-coronary Valsalva sinus, and (iii) a fistula connecting the non-coronary Valsalva sinus and the right atrium above the tricuspid plane. Furthermore, a rare echocardiographic finding was noted: a large vegetation floating in the right atrium next to the antero-septal tricuspid leaflets, not involving the tricuspid valve itself (Panels A, B, D, and E; Supplementary data online, Videos S1 and S2). A cardiac CT was performed and confirmed the echocardiographic findings. Specifically, the AV vegetations (maximum 16 × 11 mm) and the fistula (orifice diameter: 9 mm) extending from the non-coronary Valsalva sinus to the right atrium with the atrial vegetation were confirmed. The patient underwent a successful cardiac surgery for AV replacement with a mechanical prosthesis, the closure of the fistula with a bovine pericardial patch, and the resection of the vegetation in the right atrium (Panels C and F). The pathogenicity of A. urinae is well described in literature as demonstrated by the destructive aortic endocarditis. Nevertheless, this case is unique because of the finding of vegetation in the right atrium originating from the outlet of the aortic-atrial fistula, without any endocarditis involvement of the tricuspid valve.