Echocardiographic Evaluation of Patent Ductus Arteriosus in Preterm Infants

Abstract

Patent ductus arteriosus (PDA) is part of the typical morbidity profile of the preterm infant, with a high incidence of 80-90% in extremely low birth weight infants born before 26 weeks of gestation. Whereas spontaneous closure of the ductus arteriosus (DA) is likely in term infants, it is less so in preterm ones. PDA is associated with increased mortality and various comorbidities including cardiac failure, need for respiratory support, bronchopulmonary dysplasia, pulmonary or intracranial hemorrhage, and necrotizing enterocolitis; however, there is no proven causality between these morbidities and the presence of DA. Thus, the indication to close PDA remains highly controversial. This paper focuses on echocardiographic evaluation of PDA in the preterm infant and particularly on the echocardiographic signs of hemodynamic significance.

Keywords: ductus arteriosus; extremely low birth weight infant; functional echocardiography; patent ductus arteriosus; preterm infant.

Figure 1

Visualization of patent ductus arteriosus in short axis view (SAX). (A) 2D SAX moved anteriorly, (B) same picture with color Doppler, (C) Doppler in the main pulmonary artery by closed duct, and (D) Doppler in the main pulmonary artery by patent duct. MPA, main pulmonary artery; RPA, right pulmonary artery; LPA, left pulmonary artery; AAo, ascending aorta.

Figure 2

Visualization of patent ductus arteriosus (PDA) in suprasternal view. (A) Normal suprasternal view of the aortic arch, (B) suprasternal sagittal view with pulmonary artery and descending aorta, and (C) color Doppler in a sagittal suprasternal view with PDA in red.

Figure 3

Visualization of patent ductus arteriosus in long axis view (LAX). (A) 2D classical LAX, (B) LAX slightly tilted anteriorly toward the pulmonary artery, and (C) main pulmonary artery with pulmonary branches. RV, right ventricle; LV, left ventricle; AV, aortic valve; PV, pulmonary valve; MPA, main pulmonary artery; RPA, right pulmonary artery; LPA, left pulmonary artery.

Figure 4

Measurement of patent ductus arteriosus (PDA) size on suprasternal view. MPA, main pulmonary artery; RPA, right pulmonary artery; LPA, left pulmonary artery.

Figure 5

Right-to-left shunt across the patent ductus arteriosus (PDA). (A) Short axis view; color Doppler flow pattern is blue during systole and diastole, (B) flow across the PDA is below the baseline during systole, and (C) flow across the PDA is below the baseline during systole and diastole in the case of “pure right-to-left shunt.” MPA, main pulmonary artery; RPA, right pulmonary artery; LPA, left pulmonary artery.

Figure 6

Suprasternal view with (A) bidirectional shunt, (B) bidirectional shunt predominantly left-to-right, (C) left-to-right shunt on color Doppler, and (D) left-to-right shunt on color Doppler M-Mode.

Figure 7

Measurement of LA:Ao ratio in parasternal long axis view in M-Mode.

Figure 8

Suprasternal view: (A) color Doppler of the postductal descending aorta with (B) normal anterograde flow, (C) absent end diastolic flow, and (D) pandiastolic retrograde flow.

Figure 9

Subcostal view of the descending aorta abdominalis with visualization of the truncus coeliacus and superior mesenteric artery, (A) on 2D, (B) on color Doppler, (C) with anterograde flow, (D) with absent end diastolic flow, and (E) with retrograde flow. TC, truncus coeliacus; SMA, superior mesenteric artery.

Figure 10

Transductal flow on Doppler in short axis view or suprasternal view: (A,B) unrestrictive pulsatile flow and (C) restrictive continuous flow.