PURPOSE--To determine the prevalence of residual left-to-right shunt in patients submitted to closure of patent ductus arteriosus with use of Rashkind double-disc ductal occluding device, analyzing predictive factors that determine short and long-term prevalence of residual shunt. METHODS--Thirteen patients were submitted to percutaneous closure of patent ductus arteriosus with use of Rashkind double-disc device. Ten patients were male with mean age of 5.7 years. A 12mm diameter device was used in 7 cases and a 17mm device in the remaining six patients. All patients had clinical, radiological and echocardiographic follow up, after 24h, 1 month, 6 months and one year after the procedure. Morphology and length of the ductus arteriosus and the presence of residual shunt after 15 min, 24h and one year after the procedure, were correlated. RESULTS--In one case, embolization of the device to the pulmonary artery determined the in success of the procedure. Residual shunt was present in 75 of the patients after 15 min of the procedure, in 33.3 after 24h, in 25 after 1 month and 6 months and in 16.6 after 1 year. The most important and isolated predictive factor leading to a high prevalence of residual shunt after 24h and after 1 year of the procedure was the presence of ductus arteriosus diameter > or = 4.5mm at the site of its insertion in the pulmonary artery. CONCLUSION--Prevalence of residual left-to-right shunt decreases over the time, with a low incidence after one year follow-up. A higher incidence of residual shunt at 24h and 1 year after the procedure occurred in the cases where the diameter of the ductus arteriosus was > or = 4.5mm, at the site of its insertion in the pulmonary artery.