Right Coronary Artery From Aorto–Left Ventricular Tunnel: Case Report Of A New Surgical Approach

Abstract

Aorto–left ventricular tunnel is a rare congenital anomaly, which was first described by Edwards in 1961. The tunnel is a communication between the ascending aorta and the left ventricle. The right coronary artery (RCA) usually originates from the lateral wall of the aorta with a separate ostium next to the opening of the tunnel. Herein we report a case of anomalous RCA arising from the aorto–left ventricular tunnel itself. This rare anomaly, including its physiology and its surgical options, is discussed. A 14-month-old baby boy was admitted for a work-up of a heart murmur known since birth. Echocardiography demonstrated a normal aortic valve without regurgitation and preserved left ventricular function. There was an aneurysmatically dilated communication anterior and to the right of the aorta between the ascending aorta and left ventricle bypassing the aortic valve. The RCA could not be visualized. Cardiac catheterization revealed a runoff of contrast material from the ascending aorta through a tunnel into the left ventricular outflow tract (LVOT). The opening of the tunnel was located in the anterior aspect of the ascending aorta above the right coronary sinus (Fig. 1). The ostium was 4 mm in diameter and the middle part of the tunnel was enlarged up to 11 mm. The ventricular ostium in the LVOT was 8 mm in maximal diameter and was located right below the aortic valve in the conal septum. A selective injection of the tunnel showed an RCA arising from the dilated middle part of the tunnel with a large collateral vessel from the left anterior descending artery (Fig. 2, A and B). The operation was performed with cardiopulmonary bypass and moderate hypothermia (26° C). Myocardial protection was achieved by antegrade and retrograde cold blood cardioplegia. After the aorta was crossclamped, the dilated tunnel was incised longitudinally and the ostium of the RCA was found in the lateral wall, approximately 3 cm distal to the aorta. Two additional openings were clearly identified, one in the ascending aorta and the other in the LVOT, anterior to the right fibrous trigone of the heart. Both openings were closed with a single patch of autologous tissue tailored from the redundant wall of the tunnel to prevent any distortion of the right sinus of Valsalva. The RCA was excised from the tunnel wall and reimplanted into the aorta above the sinotubular junction with a resorbable running suture. The postoperative course was uneventful, and a follow-up transthoracic echocardiogram demonstrated a securely closed communication without any aortic valve incompetence. Discussion. An RCA arising from an aorto–left ventricular tunnel is a rare anomaly, very few cases having been reported in the world literature. The case presented here firmly proposes the theory of Levy and associates that the defect may be an abnormal coronary artery and that its subsequent dilatation is acquired. However, there does not appear to be any correlation between the presence of such a dilatation and the age of the patient, because such cases have also been seen in newborn infants. It is possible, nonetheless, that part of the tunnel is a result of an anomalous formation of the RCA. The distal end of the tunnel is arterial in structure, with the part through the aortic wall being distinctly reminiscent of an intramural coronary artery. Morgan and Mazur considered that the communication between the aorta and the left ventricle might result from primary separation of the aortic anulus from the fibrous skeleton, whereas others believed on the basis of histologic evidence that the condition was related to Marfan’s disease. Even a common origin with ruptured aneurysm of the sinus of Valsalva has been suggested. However, none of these theoFrom the Clinic of Cardiovascular Surgery, University Hospital, Zurich, Switzerland.