Since 2007, over a 4-year period, transcatheter closure of ASDs was performed in 105 patients.
During the study period, there were two instances of embolization of the device. The morphology of the defects in the patients with embolization was evaluated carefully, and an unusual spiral configuration of the flap valve relative to the rims of the oval fossa was noted. These findings were then found in four additional patients and serve as the focus of this report. To facilitate understanding of the unusual morphology, the clinical findings were compared with images showing the mechanism of development of the atrial septum in the mouse, revealing a striking similarity.
Although uncommon, spiral spatial orientation of the margins of ASDs predisposes to embolization of devices used for percutaneous closure. Standard cross-sectional techniques have limited use in identifying this variation. Understanding of the development of the atrial septum in the mouse heart may help explain the morphogenesis of the defect and the mechanism predisposing to embolization.