Successful coil embolization for pediatric internal mammary artery aneurysm after the Fontan procedure: A case report and literature review.

We herein describe the first pediatric case of an internal mammary artery (IMA) aneurysm caused by a median sternotomy. He was a 2-year-old with tricuspid atresia who underwent an extracardiac conduit Fontan procedure. On the 36th postoperative day, an asymptomatic left IMA aneurysm was detected via contrast computed tomography, which was successfully treated with coil embolization. The patient had no underlying disease such as vasculitis, connective tissue disease, or other hereditary diseases, and there were no episodes of infection or hypertension before or after the onset of the IMA aneurysm. Because the left IMA ran medially to the periphery and was in a vulnerable position during median sternotomy, we considered the IMA aneurysm was caused by the median sternotomy. We pediatric cardiologists should be aware that IMA aneurysms can occur in pediatric cardiac surgery, and we should be proactive in performing postoperative imaging studies in cases where the preoperative internal thoracic artery runs medially toward the periphery. Learning objective: Internal mammary artery (IMA) aneurysm is a rare vascular disease, especially in children. One-third of adult IMA aneurysms have been reported to be caused by sternotomy, but not in children. We report the first pediatric case of an IMA aneurysm caused by sternotomy. We should recognize that there is a potential risk of IMA aneurysms in pediatric cardiac surgery as well.