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Diagnosis of patent ductus arteriosus
1Department of Paediatrics, Green Lane Hospital, Green Lane West, Auckland, New Zealand. jskinner@ahsl.co.nz
Insights
Clinical signs are unreliable for detecting left-to-right shunting in preterm infants. Echocardiography is essential for assessing haemodynamic features and shunt size, aiding in diagnosis and management.
Area of Science:
- Neonatal Medicine
- Pediatric Cardiology
- Medical Imaging
Background:
- Clinical signs are insufficient for diagnosing left-to-right shunts in preterm neonates.
- Accurate assessment of haemodynamic status is crucial for managing preterm infants.
Purpose of the Study:
- To review the diagnostic capabilities of echocardiography for left-to-right ductal shunting in preterm infants.
- To establish echocardiographic criteria for categorizing shunt severity.
Main Methods:
- Review of existing literature on echocardiographic assessment of ductal shunts.
- Analysis of haemodynamic parameters and anatomical measurements.
Main Results:
- Echocardiography effectively identifies haemodynamic features, including ventricular dysfunction.
- Criteria for large shunts include elevated left atrial:aortic root ratio, ductal diameter >1.4 mm, and retrograde diastolic flow >30%.
Conclusions:
- Echocardiography is superior to clinical signs for evaluating ductal shunts in preterm infants.
- Awareness of occult congenital heart disease is vital before ductal closure.
Abstract:
This review shows that clinical signs cannot be relied on to reveal left-to-right ductal shunting in the preterm. Echocardiography can define many of the haemodynamic features, including occult ventricular dysfunction, and categorize shunts into small, moderate or large, without defining "significance" which is multifactorial. Large shunts have an elevated left atrial:aortic root ratio (>1.3:1 or >1.5:1, depending on fluid and diuretic policy) a ductal diameter >1.4 mm and retrograde diastolic flow in the descending aorta exceeding 30% of the antegrade flow. The neonatal clinician and echocardiographer is reminded to remain wary of occult congenital heart disease, particularly before closing the ductus.