Relationship of Patent Ductus Arteriosus Size to Echocardiographic Markers of Shunt Volume

Objective To define the technique of estimating ductal diameter (DD) that best correlates with echocardiographic markers of transductal shunt volume in preterm infants >7 days old with persistent patent ductus arteriosus (PDA). Study design We conducted a retrospective study of 104 neonates born at Results Two hundred echocardiograms were reviewed from 104 patients with a median gestational age of 25.4 weeks (range, 25-26.3 weeks) and a median birth weight of 810 g (range, 740-920 g). We found a weak correlation of each method of PDA size definition with individual echocardiographic markers of transductal shunt volume, of which nonindexed DD demonstrated the best correlation. The best correlation was found with markers of systemic hypoperfusion, such as diastolic flow reversal in the descending aorta ( R 2 = 0.24) and celiac artery ( R 2 = 0.21). Markers of pulmonary overcirculation, such as left ventricular end-diastolic diameter ( R 2 = 0.19) and left ventricular output ( R 2 = 0.17), showed fair correlation with nonindexed DD. Conclusion In preterm infants >7 days old with PDA, nonindexed DD demonstrated weak correlations with individual echocardiographic markers of shunt volume. These data highlight the need for comprehensive echocardiographic evaluation in addition to diameter measurements to provide a better understanding of the hemodynamic consequences of PDA.