Case report

A 14-year-old boy was referred to us for recurrent aortic stenosis after balloon aortic valvoplasty. He was diagnosed with a congenitally stenotic aortic valve with two leaflets at 6 months of age, and underwent transcatheter balloon dilation at 8 years of age. At 14 years of age, the aortic stenosis progressed rapidly, concomitant with the increase in the body-frame. Electrocardiography indicated left ventricular hypertrophy and exertional depression of the ST segment, and cardiac catheterization revealed the peak transaortic pressure gradient as 59 millimetres of mercury. Three-dimensional cardiac images obtained by multidetector computed tomography clearly demonstrated that the right coronary artery originated abnormally from the aortic sinus, giving rise to the main stem of the left coronary artery (Fig. 1a). The patient was advised elective surgery by his paediatric cardiologist. Echocardiography revealed normal function of the pulmonary valve. After discussing the potential options with the patient and his parents, we elected to proceed with a Ross procedure, arguing that the pulmonary autograft would allow for his further growth and avoid the risks of a mechanical valve.

Figure 1. Three-dimensional cardiac images by multidetector computed tomography. (a) Preoperative. (b) Postoperative. Ao: Aorta, PA: pulmonary trunk.

The operation was performed using standard cardio-pulmonary bypass and moderate hypothermia. Myocardial protection was achieved with combined ante- and retrograde cold blood cardioplegia. At the operation, the bifoliate nature of the stenotic aortic valve was confirmed, the thickened leaflets being positioned anteriorly and posteriorly. A raphe was located in the anterior leaflet. The origins of the coronary arteries arose very close to each other, and were positioned to the left of the raphe compartmenting the anterior leaflet of the bifoliate valve. The anomalous right coronary artery passed forward between the two great arteries, running within the tissue plane between the aortic root and the free-standing muscular subpulmonary infundibulum. The patient underwent a Ross procedure employing the mini-root replacement technique. We excised a single rectangular button incorporating the orifices of both coronary arteries from the aortic wall (Fig. 2), reimplanting it into the reconstructed aortic root. The diameters of the aortic and pulmonary roots measured 22 and 23 millimetres, respectively. The free-standing subpulmonary muscular infundibulum was excised carefully completely to avoid injuring the first septal branch of the left anterior descending artery, as well as the anomalous right coronary artery coursing between it and the aortic root. The pulmonary autograft was attached to the left ventricular outflow tract, and the coronary arterial button was reimplanted into the pulmonary autograft, above the reconstructed sinutubular junction (Fig. 2). The right ventricular outflow tract was reconstructed with a 25 millimetre cryopreserved pulmonary valvar allograft. The patient was extubated on the first postoperative day. Three-dimensional cardiac images obtained by multidetector computed tomography prior to discharge revealed satisfactory reimplantation of the coronary arteries, with no evidence of either kinking or compression by the adjacent pulmonary allograft (Fig. 1b). Postoperative echocardiography showed no aortic stenosis, with trivial regurgitation and normal left ventricular ejection fraction. The patient was in the first class of the system devised by the New York Heart Association at 1 year and 4 months after the operation.

Figure 2. Reimplantation of the orifices of both coronary arteries as a single rectangular button. *: orifice of right coronary artery.

Discussion

The Ross procedure using the pulmonary autograft is preferred for replacement of the aortic valve in young and active patients because it has no requirement for life-long anticoagulation,⁴ low rates of valve-related deaths and complications,⁵ and excellent haemodynamics of the aortic valve at rest and during exercise.⁶ For all these reasons, this procedure was selected for our adolescent patient.

In our patient, however, the right coronary artery originated abnormally from the same component of the aortic root that gave rise to the main stem of the left coronary artery. Application of the Ross procedure in our patient then raised two important technical issues. One was the possible injury to the abnormal right coronary artery, which passed forward between the aortic root and the free-standing subpulmonary infundibulum, on harvesting the pulmonary trunk. Despite this potential problem, we successfully excised the pulmonary autograft, and reconstructed the right ventricular outflow tract with care. Multidetector computed tomography was extremely helpful in visualizing the geometric relations between the pulmonary trunk and the coronary artery, and estimating the related risk. The second issue was the reimplantation of the coronary arteries. The anatomy was not suitable for excising the two arterial orifices as separate buttons, since little margin of the aortic wall would have been left on their adjacent sides. Because of this, we excised both orifices within a single arterial button. This technique has already been used when performing the Ross procedure in two patients associated with anomalous origin of the circumflex coronary artery,⁷ and when the orifices of the coronary arteries were located eccentrically on either sides of the zone of apposition between the leaflets guarding the right and left aortic sinuses.⁸ These anomalies, of course, are subtly different from the one observed in our patient. Multidetector computed tomography revealed neither compression of the transplanted orifices by the reconstructed pulmonary trunk, nor kinking of the right coronary artery as it continued to pass forward between the two great arteries. Thus, our experience validates the feasibility of the Ross procedure in patients with anomalous origin of the right coronary artery from the left coronary aortic sinus.

Acknowledgments

We are grateful to Dr. Yoshihiko Kurimoto for management and preparation of the allograft, Prof. Tomio Abe for the supervision, and Dr. Hideshi Tomita who continues to care for the patient reported.