Objective: The purpose of this study is to evaluate the position and the progress of large Amplatzer septal occluder (ASO) devices relevant to adjacent cardiac structures in growing children using MRI.
Materials and methods: Institutional review board approval for this study was obtained. Twenty-five children who underwent large ASO implantation were evaluated using MRI. All subjects were initially imaged 7 years earlier using the same protocol. Spatial and dynamic relationships between the ASO and the adjacent cardiac structures were compared to assess the progress over the 7-year growth span with respect to protrusion, contact, and extrinsic deformity of the mitral valve, the left atrial roof, the aortic annulus and root, and the ostia of adjacent veins.
Results: No long-term device-related complications were documented during follow-up. Impingement of the ASO into the opening of the right superior and inferior pulmonary veins and the superior and inferior vena cava resolved completely, compared with initial observations, in five of 16, three of three, five of 10, and three of nine patients, respectively, and significantly regressed in the remaining patients. The device's contact with the mitral valve and the left atrial roof and the aortic root deformity resolved in seven of 10, 11 of 20, and 10 of 18 cases, respectively.
Conclusion: The distance between the ASO and the surrounding structures increases with time in growing children who require large ASO devices, likely decreasing the risk of long-term complications.