Improving the results of ligation of patent ductus arteriosus in small preterm infants.

Thirty-two consecutive preterm infants with birth weights under 1,500 grams and with respiratory distress syndrome (RDS) complicated by a patent ductus arteriosus (PDA) underwent ligation of PDA. The indications for operation were massive left-to-right shunting associated with heart failure (cardiomegaly and pulmonary edema) unresponsive to medical treatment. The clinical manifestations of heart failure were related to the severity of RDS. Infants with mild-to-moderate RDS (21) often recovered and later developed typical findings of PDA (bounding pulses, hyperactive precordium, and murmur). They are now operated upon as soon as respiratory support is required. Infants with severe RDS (11) develop cardiomegaly earlier, and retrograde aortography may show massive left-to-right shunting before the presence of a murmur. Ligation is indicated when blood-gas values deteriorate despite medical treatment. Nineteen (59 per cent) of these extremely preterm infants survived to be discharged and 16 (50 per cent) are developing normally. Three have neurologic impariment. None of the survivors has clinical respiratory disease, and their radiologic findings of bronchopulmonary dysplasia are improving.