EComment. Coronary lesions after arterial switch operation: Is there a place for minimally invasive direct coronary artery bypass?

Abstract

Jill Jussli-Melchers and collaborators report the case of a patient who underwent neonatal arterial switch operation (ASO). At the age of 5 years, occlusion of the left main coronary artery was diagnosed. Because of worsening symptoms, a minimally invasive coronary bypass (left internal mammary artery to left anterior descending artery) was performed at the age of 13 years. One year later, the mammary bypass was patent at magnetic resonance imaging (MRI) evaluation [1]. The authors should be congratulated for achieving a satisfactory early outcome. However, we do not agree with the conclusions and we think that several comments are raised by this case report. Following ASO, coronary lesions are not uncommon. They are more frequent in patients with unusual coronary patterns, but they may occur in all patterns. Most do not show clinical, electrocardiographic or echocardiographic symptoms of myocardial ischaemia. Coronary lesions are progressive and need serial coronary evaluation [2]. Our policy is to perform a first evaluation before the age of 5 years. If coronary lesions are detected, coronary revascularization is indicated in patients in whom myocardial ischaemia at rest or under stress is demonstrated, and strongly recommended even in the absence of objective signs of myocardial ischaemia [2]. Surgery is thus usually performed in young children. We think that the present patient should have undergone surgery much earlier. When coronary revascularization is indicated, optimal coronary perfusion should be restored to better preserve the future of the patients. We do not think that using a single mammary bypass is the best option to revascularize a complete left main coronary territory. The coronary flow which is provided (partially in a retrograde way) may be inadequate to perfuse a large myocardial area, particularly in children (in whom the mammary artery may be small). On the contrary, patch coronary arterioplasty restores a normal antegrade physiologic coronary perfusion, with growth potential [2]. Coronaroplasty can be performed with a very low operative risk and a high patency rate. In our experience with coronary revascularization in children, coronary arterioplasty provided better long-term results than mammary bypass [3]. Although technically feasible in the vast majority of patients, there are very rare circumstances in which coronary patch arterioplasty is not possible. This is the case when there is a long occluded segment between the aorta and the patent coronary artery. Mammary bypass is then indicated. To obtain optimal flow and patency, we believe that the mammary artery should be implanted as proximal as possible (on the distal main trunk or, at least, on the proximal left anterior descending artery). This is best achieved through a median sternotomy and after transection of the anteriorly reconstructed main pulmonary artery. A mammary bypass implanted on a small distal left anterior descending artery (LAD) is, in our opinion, far from optimal. A second skin incision (anterior thoracotomy) is added to the previous sternotomy; the cosmetic advantage is questionable, particularly due to the potential harm on breast development. Repeat sternotomy and cardiopulmonary bypass cannot be considered as significant risk factors in experienced centers of paediatric and congenital cardiac surgery. Finally, if late reoperation becomes necessary (i.e. for aortic insufficiency or ascending aorta aneurysm) repeat sternotomy with a patent mammary bypass may be hazardous. To summarize, we believe that patients with coronary obstructions after ASO should undergo revascularization, usually using proximal coronary arterioplasty and, occasionally, using a mammary bypass performed under sternotomy and cardiopulmonary bypass. There is, in our opinion, a very limited place, if any, for minimally invasive direct coronary artery bypass. Conflict of interest: none declared.