Radiographic and echocardiographic evaluation of newborns treated with indomethacin for patent ductus arteriosus.

A series of 33 consecutive preterm newborns who were treated with indomethacin, a drug which acts to close the patent ductus arteriosus, were studied retrospectively to examine the efficacy of chest radiography and echocardiography in diagnosing the presence of a significant patent ductus arteriosus. Radiographic changes in pulmonary vascular engorgement, pulmonary edema, and cardiac size on the anteroposterior film tended to precede the clinical changes of shunt appearance and resolution. The echocardiographic left atrial to aortic ratio (LA/Ao) supplemented the radiographic findings. The time of disappearance of the ductus arteriosus shunt, as judged by clinical findings, was identified accurately by radiographic and echocardiographic findings in the majority of cases; errors of under- and overestimation occurred in a minority of patients. In assessing both the presence and the resolution of the shunt, greater reliability was possible by using both radiographic and echocardiographic findings than by using either method alone.