Table 5.

Mechanisms for Device Protrusion

Device Size	Implanted device is too large for the encountered anatomy
Delivery System	Anterior tension on the device by delivery wire. Delivery catheter preventing device to stay co-axial along the length of the duct
Inadequate Imaging	Inability to adequately visualize location of aortic disc relative to aorta. Relying exclusively on temperature probe to identify aortic end of the ductus
Ductal Vasoconstriction	Post-procedure ductal vasoconstriction on pulmonic end causes device to be pushed out of aortic end; or vasoconstriction causing device lengthening
Device Malposition	Device positioned in small infant (≤ 2 kg) with one or both discs in an extraductal position. Difficulty in device positioning due to ductal distortion by delivery catheter
Operator related	Device pulled inadvertently into left pulmonary artery during or after deployment. Prolonged time interval between device placement and release
Migration	Device migrates following device release
Duct Orientation	Acute angulation of the ductus relative to the descending aorta resulting in more exposure of the superior edge of the aortic disc into the aortic lumen