Objectives To investigate and correlate clinical signs of PDA with echocardiographic findings beyond day 5 of life in preterm infants.
Methods Infants ≤33 weeks of gestation and ≤2.0 kg were included in this prospective observational study. The patients with acute illness (eg Sepsis, NEC) and with congenital heart defect were excluded. Demographic (gestational age, birth weight, gender and Apgar scores), clinical (presence of murmur, blood pressure and pulse pressure) and echocardiographic parameters (presence of PDA, PDA size, flow velocity and LA/Ao) were collected.
Results 29 neonates met the study criteria and 61 echocardiograms were performed. All except one (VSD) had a structurally normal heart on echocardiogram and the remainder had a PDA alone. 19/28 had both a murmur and PDA while 9 patients had a PDA without a murmur. The mean PDA size in neonates with a clinical murmur was greater than those with no clinical murmur (0.25 vs. 0.16 cm; p < 0.05). 9/28 neonates had a wide pulse pressure and 19 had a normal pulse pressure. These infants were relatively of larger gestations and day 7 or older. The LA/Ao ratio was >1.2 in 18/28 patients and only 5 had wide pulse pressure.
Conclusion Clinical findings alone cannot diagnose a PDA in preterm infants and echocardiogram is required to exclude abnormal anatomy and confirm the presence of a PDA. The pulse pressure is more relevant within first 7 to 10 days of life.