ALCAPA is a rare congenital, coronary artery malformation with a reported incidence of 1/300,000 live births, accounting to 0.25–0.5% of all diagnosed cases of congenital heart diseases . In ALCAPA, the LCA that originates from the PA causes myocardial ischemia in the LCA region. The neonatal closure of the ductus arteriosus and physiological reduction in the pulmonary vascular resistance results in early occurring left-ventricular dysfunction and ischemic mitral regurgitation. As a result, over 90% of neonatal patients diagnosed with ALCAPA die within 1 year of birth. However, because of the development of a collateral circulation from the RCA, a small number of such patients survive until adulthood without suffering from myocardial ischemia. Nevertheless, even in such asymptomatic cases, sudden death may occur due to coronary steal; therefore, immediate surgical intervention is necessary after diagnosis . In the present case, exercise load electrocardiogram and adenosine-loading myocardial scintigraphy indicated the presence of myocardial ischemia.
In ALCAPA, it is necessary to revascularize the arterial blood to improve the perfusion of the LCA. The most physiologically compatible method of revascularization is to directly transplant the origin of the LCA to the aorta; however, in adults the mobility of the tissues surrounding the LCA are poor, making transplantation difficult. Several tunneling method had been reported and the Takeuchi repair has been proposed. In Takeuchi repair method, a tunnel in the wall of the main PA is constructed from the LCA to the ascending aorta . Although several adult patients have been treated using this procedure have been reported, stenosis within the tunnel or just above the pulmonary valve is reported as the long-term complications . Therefore, alternate procedures involving aortic or PA wall flaps to extend the LCA and those for performing coronary artery bypass surgery with LCA ligation have been reported [5,6,7,8,9]. As the number of cases of adults with ALCAPA is less, no standard surgical approach has yet been defined. We selected our method for two main reasons.
Firstly, all these procedures require skillful techniques to prevent the bending or occlusion of the blood flow path leading to the LCA including the tunnel. Secondly, the size mismatch between the graft and dilated coronary artery is of concern when performing coronary artery bypass. In our procedure, stenosis in the PA due to the presence of the vascular prosthesis and thrombosis in the vascular prosthesis can become problematic. However, in the present case, we assumed that the 6 mm vascular prosthesis will not affect PA stenosis because the diameter of the main PA is sufficiently large (25 mm). Moreover, postoperative echocardiography revealed no findings suggesting stenosis in the main PA. Thrombus formation in the vascular prosthesis was prevented using aspirin and warfarin. However, long-term outcomes of this technique remain unclear, to the best of our knowledge, there are no reports regarding reconstruction using vascular prosthesis in patients with ALCAPA. Since, in our case, there has been no problem in postoperative course for 2 years, we consider that reconstruction of ALCAPA using vascular prosthesis is useful.