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Centering-on-demand buttoned device: its role in transcatheter occlusion of atrial septal defects.

Since the initial design and description of the buttoned device, it has undergone a number of design changes. Introduction of radiopacity in the knot (button) made it easier to visualize and document that buttoning has indeed occurred. Introduction of two buttons has markedly decreased the unbuttoning rate with potential for eliminating it. A centering mechanism was then incorporated into the device, which allowed closure of larger defects and use of smaller-sized devices. For some unknown reason, unbuttoning rate no longer occurs since the introduction of this device. The centering-on-demand (COD) device also appears to have increased the effective occlusion rates. At the present time, however, no long-term follow-up data are available to assess the long-term efficacy of the new device. Experience in a larger number of patients and evaluation of follow-up data are necessary to confirm the safety and efficacy observed in the small cohort reported in this review.