EARLY ECHOCARDIOGRAPHIC PREDICTION OF SYMPTOMATIC PATENT DUCTUS-ARTERIOSUS IN PRETERM INFANTS UNDERGOING MECHANICAL VENTILATION

Objective: To identify early echocardiographic markers allowing predic tion of subsequent symptomatic patent ductus arteriosus (PDA). Methods : One hundred sixteen preterm infants (<1500 gm) requiring mechanical ventilation underwent echocardiography at a mean postnatal age of 19 h ours (range, 7 to 31 hours). Four potential markers were studied: the left atrial to aortic root ratio, pulsed Doppler measurement of left v entricular output, the minimum diameter of the color Doppler signal wi thin the course of the duct (ductal diameter), and the direction of po stductal aortic diastolic flow. Subsequent ductal closure or significa nt patency (if suspected clinically) was confirmed echocardiographical ly. Results: A significant PDA developed in 42 infants (36%). Ductal d iameter was the most accurate echocardiographic marker in predicting s ubsequent significant PDA. With a ductal diameter of 1.5 mm or greater there were 34 true-positive, 11 false-positive, 63 true-negative and 8 false-negative results, giving a positive likelihood ratio of 5.5 an d a negative likelihood ratio of 0.22 for prediction of development of PDA requiring treatment. The sensitivity was 81% and the specificity was 85%. Only one infant older than 28 weeks of gestational age had a significant PDA, and limiting the analysis to infants younger than 29 weeks of gestation further improved the predictive accuracy of ductal diameter. The positive likelihood ratio was 8.1 and th negative likeli hood ratio was 0.19, with a sensitivity of 83% and a specificity of 90 %. Conclusion: Color Doppler measurement of the internal ductal diamet er allows early prediction of significant PDA in preterm infants.