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Longitudinal changes in the diameter of the ductus arteriosus in ventilated preterm infants: correlation with
1Department of Perinatal Medicine, King George V Hospital for Mothers and Babies, Sydney, NSW, Australia.
Insights
Early ductal shunting in preterm infants impacts short-term respiratory outcomes. While spontaneous closure is common, symptomatic patent ductus arteriosus (PDA) may enlarge, especially in less mature infants, affecting oxygenation.
Area of Science:
- Neonatal Medicine
- Pediatric Cardiology
- Respiratory Physiology
Background:
- Patent ductus arteriosus (PDA) is common in preterm infants.
- The early natural history and respiratory implications of ductal shunting require further investigation.
Purpose of the Study:
- To analyze the early natural history of ductal shunting in ventilated preterm infants (<1500g).
- To assess the association between ductal shunting and respiratory outcomes.
Main Methods:
- Echocardiography was used to measure ductal diameter and postductal aortic diastolic flow (PADF) in 48 infants.
- Infants were categorized based on ductal diameter progression and symptoms.
- Logistic regression analyzed correlations with respiratory parameters.
Main Results:
- Normal antegrade PADF correlated with ductal diameter ≤1.5 mm; abnormal flow with diameter >1.5 mm.
- Three ductal progression groups identified: spontaneous closure, enlarging symptomatic PDA, and minimally constricting symptomatic PDA.
- Ductal shunting correlated with oxygenation index but not ventilator or oxygen days; gestation was linked to longer respiratory support.
Conclusions:
- The preterm ductus arteriosus exhibits diverse postnatal constrictive patterns.
- Symptomatic PDAs typically show delayed constriction.
- Ductal shunting independently influences short-term respiratory outcomes in preterm infants.
Abstract:
This study aimed to examine the early natural history of ductal shunting in ventilated preterm infants (< 1500 g) and to document the association between this shunting and respiratory outcomes. The size of the ductal shunt was assessed in 48 infants using serial echocardiographic measurement of colour Doppler internal ductal diameter and pulsed Doppler postductal aortic diastolic flow (PADF). At all postnatal ages, normal antegrade PADF was invariably seen when the ductal diameter was 1.5 mm or less, and was usually abnormal (absent or retrograde) when more than 1.5 mm. Longitudinal progress of ductal diameter fell into three groups: (i) asymptomatic spontaneous closure (n = 31)--in 20 of these infants closure occurred within 48 hours; (ii) symptomatic PDA which enlarged after a postnatal constriction (n = 9); and (iii) symptomatic PDA that showed minimal postnatal constriction (n = 8). Infants in group 2 were significantly less mature and had PDAs which became symptomatic significantly later than those in group 3. Logistic regression showed that ductal shunting had a significant correlation with mean oxygenation index over the first five days but not with ventilator or oxygen days. Gestation had the most significant association with the latter two variables, with atrial shunting also being related to days in oxygen. The preterm duct displays a wide spectrum of postnatal constrictive activity. Symptomatic PDAs usually showed slower early postnatal constriction. Ductal shunting independently related to short term but not long term respiratory outcomes.