OBJECTIVE: To assess the immediate and mid-term results of transcatheter closure of patent ductus arteriosus (PDA) > or = 4 mm with multiple Gianturco coils. (Transcatheter closure of large PDAs using the Rashkind occluder or the buttoned device is associated with a 7-38% incidence of residual shunt.) METHODS: 19 patients (7 male, 12 female) underwent an attempt at anterograde transcatheter closure with multiple Gianturco coils of a large PDA at a median age of 3.8 yr (range 2 weeks-34 yr) and median weight of 14 kg (range 2.3-80 kg). RESULTS: The median PDA diameter at the narrowest segment was 4.3 mm (range 4-7 mm) and the mean (SD) Qp/Qs was 1.9 (0.8). Each patient had left atrial and left ventricular volume overload. A 4F catheter was used to deliver the coils in all patients. There was immediate and complete closure in 16/18; one patient had residual shunt that was closed at a second procedure and the other had spontaneous disappearance of the residual shunt at the six week visit. A short ductus (angiographic type B) in one patient could not be closed. The median number of coils placed at the first attempt to close the ductus was 4 (range 2-6 coils) and the median fluoroscopy time was 40 minutes (range 13-152 minutes). Mild left pulmonary artery stenosis occurred in the two smallest patients. Coil migration to the lung occurred in 3 patients with retrieval of coils in two patients. All procedures but one were done on an outpatient basis. At a median follow up of 1.6 yr (range 2 weeks-2.2 yr) all patients had complete closure with no new complications. CONCLUSIONS: Anterograde transcatheter closure with multiple Gianturco coils is an effective treatment for most patients with large PDA of diameters up to 7 mm. This technique can be performed in small infants on an outpatient basis without the need for general endotracheal anaesthesia.