We have used two methods to maintain ductal ppatency in 13 newborns during surgery for congenital cardiac malformations: prostaglandin E1 (PGE1) infusion for the short-term and formaldehyde infiltration of the ductus arteriosuos (FID) for the longer term. PGE1 increased the arterial oxygen saturation, leading to stable intraoperative hemodynamics in the six infants in whom it was used. FID was used in all 13 patients. Four of these patients died in the hospital, all with the ductus open. Of the nine early survivors, all required an additional shunt procedure. The five long-term survivors had the second palliative operation immediately, three hours, three days, two and one-half months, and four and one-half months after FID. We continue to use PGE1 to maintain ductal atency through operation, but use aortopulmonary anastomosis in the newborn period rather than FID.