when can we release the amplatzer ductal occluder (ado) safely?

background: the ductus arteriosus connects the main pulmonary trunk to the descending aorta. the incidence of isolated patent ductus arteriosus (pda) in full-term infants is about 1 in 2000. the amplatzer ductal occluder (ado) is recommended for pdas with sizes larger than 2 mm. in this procedure, we must confirm the ado position in pda by aortogram from the arterial line. the purpose of this study was to determine the optimal release time of the ado in the pda closure procedure, especially in the absence of an arterial line for post-pda aortography. methods: this study recruited all patients scheduled to undergo pda transcatheter closure with the ado between september 2009 and september 2012 in our center. age, weight, pda diameter, systolic and diastolic pulmonic pressures, fluoroscopy time, and total angiographic time were studied. major complications such as mortality and vascular complications were considered. results: w e studied 237 patients in our investigation. we had 130 female and 107 male patients at a mean age of 34.3 ± 40.6 months and mean weight of 14.2 ± 7.8 kg. pda sizes ranged from 2.1 to 6.2 mm and its mean was 3.7 ± 1.8 mm. mean of fluoroscopy time was 11.4 ± 9.7 min and mean of total angiographic time was 42.0 ± 12.3 min. there were no significant complications. conclusion: w e herein describe a new sign, which proved extremely helpful during our pda closure procedures with the ado. by considering the angle between the ado and the cable during the procedure, the operator can release the ado safely.