We have previously described the detection of aortopulmonary collaterals(APCs) by color flow Doppler in 7 premature infants with chronic lung disease. Ninety-six premature infants with birth weight <1500 gm were admitted to the neonatal intensive care unit from 8/95 to 8/96, 64 of them received serial echocardiographic evaluations at 1 to 2 days, 2 weeks, and at 1, 2 and 3 months of life. Fifty-one patients (78%) had evidence of APCs at 1 to 90 days of life (mean 27 days), only 1 had APCs detected in the first study. There was no significant difference in gestational age, birth weight, surfactant therapy, time on assisted ventilation, time on oxygen therapy, diagnosis of chronic lung disease between the patients with evidence of collaterals and those with no collaterals. Six/47 patients had signs of significant left to right shunt evidenced by cardiomegaly on chest x-ray and left atrial dilatation on echocardiogram and were started on digoxin and diuretics with clinical improvement. The collaterals tend to become smaller with time, and by the time of the last echocardiogram they could not be visualized in 18 (35%) subjects.

APCs are more prevalent in premature infants than previously reported. We postulate that they are bronchopulmonary communications that enlarge and/or proliferate with the physiologic changes associated with premature birth adaptation. Although we found no evidence of volume overload in the majority of subjects, any degree of left to right shunt may contribute to the development of pulmonary edema in infants with hyaline membrane disease leading to the exudative phase of chronic lung disease.

Echocardiographic examination with color flow Doppler performed in premature infants to evaluate left to right shunts should include careful search for APCs. The role of diuretics to decrease lung fluid needs consideration.

Funded by Hastings Foundation.