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Valve-incompetent foramen ovale in premature infants with ductus arteriosus: a Doppler echocardiographic study
Insights
In neonates with a patent ductus arteriosus, a leaky foramen ovale often coexists, causing left atrial enlargement. This atrial shunt typically resolves when the ductus closes, indicating its link to ductal shunting.
Area of Science:
- Neonatal Cardiology
- Pediatric Echocardiography
- Congenital Heart Defects
Background:
- Patent ductus arteriosus (PDA) is common in neonates.
- Interatrial shunting through a patent foramen ovale (PFO) can occur with PDA.
- Left atrial enlargement is a known consequence of significant left-to-right shunting.
Purpose of the Study:
- To investigate the prevalence and characteristics of interatrial shunting in neonates diagnosed with PDA.
- To assess the relationship between atrial shunting, left atrial size, and PDA severity.
- To evaluate the Doppler echocardiographic findings of valve-incompetent foramen ovale in this population.
Main Methods:
- Doppler echocardiography was used to confirm PDA in 56 neonates.
- Assessment for turbulent flow at the atrial level (valve-incompetent foramen ovale) was performed.
- Left atrial dimensions and morphology were measured and analyzed.
- Comparison of hemodynamic findings between neonates with and without atrial shunting was conducted.
Main Results:
- 33 (59%) of neonates with PDA had a valve-incompetent foramen ovale with left-to-right flow.
- Left atrial dimensions were significantly larger in neonates with atrial shunting.
- Atrial shunting resolved upon closure of the PDA and regression of left atrial enlargement.
- Doppler flow patterns of valve-incompetent foramen ovale were similar to secundum atrial septal defects.
- Valve-incompetent foramen ovale indicated a relatively large ductal shunt.
Conclusions:
- A valve-incompetent foramen ovale is a frequent finding in neonates with PDA.
- The presence of an atrial shunt is associated with increased left atrial size, reflecting ductal shunt volume.
- Doppler echocardiography effectively identifies and characterizes atrial shunting in neonates with PDA.
- Resolution of atrial shunting post-ductal closure supports its hemodynamic significance in relation to PDA.
Abstract:
In a 1 year period, 56 neonates with a clinical diagnosis of ductus arteriosus had Doppler echocardiographic confirmation of the ductus; 33 (59%) had additional, turbulent left to right flow at the atrial level through a valve-incompetent foramen ovale. Normalized left atrial dimensions in the group with the atrial shunt were significantly larger than when there was a competent foramen ovale; when the ductus closed and left atrial enlargement receded, the atrial shunt disappeared. However, several infants with large left chambers had no interatrial shunting. When the atrial shunt was present, there were up to three flow pulses, corresponding to atrial systole, ventricular systole and ventricular diastole, but these were frequently fused into two pulses or even one pulse per cycle. The atrial septal morphology provided supporting clues: general bowing of the septum or a localized bulge in the region of the foramen ovale indicated relatively high left atrial pressure, and frequently a slitlike dropout could be seen at the superior edge of the foramen. During the study, three additional neonates with a ductus arteriosus were found to have a secundum atrial septal defect with a typical echographic image, "matchhead" appearance of the septal rim of the defect, but the Doppler flow patterns were indistinguishable from those of a valve-incompetent foramen ovale. The hemodynamic effects of the interatrial shunt, from either cause, seemed slight during the hospital course, but the presence of a valve-incompetent foramen ovale indicated a relatively large ductal shunt. Quantification of the ductal shunt, however, continues to rely primarily on measurement of the left atrial and ventricular size.