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CC BY-NC-ND 4.0 · Journal of Fetal Medicine 2025; 12(01): 053-056
DOI: 10.1055/s-0045-1810414
Case Report

Prenatal Diagnosis of Aortopulmonary Window: A Case Report

Ruchi Gupta 
1   Department of Radiodiagnosis, Indira Gandhi Institute of Medical Sciences Patna, Bihar, India
,
Aishwerya Singh
2   Consultant Radiologist, Bihar Diagnostics and Radiology Centre, Patna, Bihar, India
,
Priyanshi Yadav
1   Department of Radiodiagnosis, Indira Gandhi Institute of Medical Sciences Patna, Bihar, India
,
Richa Tiwari
3   Consultant Radiologist, Dr Richa Ultrasound and Color Doppler Centre, Saharanpur, Uttar Pradesh, India
,
Zohra Ahmad
4   Consultant Radiologist, Ava Clinics and Fetal Centre, Guwahati, Assam, India
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Abstract

We report a rare case of a 31 year old female with no risk factors who came for a second opinion for a double outlet right ventricle transposition of great arteries type at 32 weeks of gestation. Fetal echocardiography was done, which showed abnormal communication between the main pulmonary artery and the ascending aorta. Diagnosis of aortopulmonary window was made, which was confirmed postnatally on echocardiography and computed tomography pulmonary angiography.


 

Keywords

fetal echocardiography - aortopulmonary window - red dot sign - ultrasound - right ventricular outflow tract

Case Report

A 31 year old female, G2A1, presented for a second opinion for double outlet right ventricle transposition of great arteries (DORV-TGA type) at 32 weeks. Her previous pregnancy had a spontaneous miscarriage at 5 to 6 weeks, followed by dilatation and curettage. There was no history of maternal cardiac disease, hypertension, or diabetes. It was a nonconsanguineous marriage with no family history of any congenital cardiac disease. A midtrimester anomaly scan done elsewhere was reported as normal. On ultrasonographic examination, fetal growth and Doppler parameters were normal. On fetal echocardiography, normal cardiac and abdominal situs and levocardia were seen ([Fig. 1]). Normal atrioventricular, ventriculoarterial, and venoatrial connections with normal cardiac rate and rhythm were noted. On an axial cardiac sweep, a defect was seen between the main pulmonary artery (MPA) and the ascending aorta ([Video 1]). On a circle sausage view of the right ventricular outflow tract (RVOT), wide abnormal communication between the MPA and the ascending aorta was noted above the semilunar valves, with color Doppler showing aliasing with a red dot at the site of defect (red dot sign) ([Video 2]). Color Doppler settings included a high frame rate, small size of color box, high velocity scale > 30 cm/sec to avoid aliasing, high filter, low color persistence, optimal color gain, and high gray scale color Doppler balance. The three vessel trachea view showed the aortopulmonary (AP) window defect and high confluence of the V sign ([Fig. 2]). The aortic arch and branches appeared normal ([Fig. 3]). Branch pulmonary arteries arising from the MPA and AP window (APW) defect were better seen in the lateral sweep of the heart ([Video 3]).

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Fig. 1 Axial 4-chamber view of heart showing levocardia and normal cardiac axis (60 degrees).

Video 1 Axial sweep of heart showing the defect between the main pulmonary artery and the ascending aorta.

Video 2 Circle sausage right ventricular. Outflow tract view showing the aortopulmonary (AP) window and red dot sign.

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Fig. 2 The three-vessel trachea view shows the aortopulmonary (AP) window defect (white arrow) and high confluence of V sign.

Video 3 Lateral sweep of heart showing the branch pulmonary arteries and aortopulmonary window (APW) defect, better seen in this sweep due to perpendicular orientation to the ultrasound beam.

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Fig. 3 Normal aortic arch seen.

The patient was referred to a tertiary center. A 3-kg healthy female baby was delivered at 36 weeks by cesarean section. On postnatal echocardiography, an APW was confirmed with a large ostium secundum atrial septal defect. The latter is difficult to diagnose prenatally. Computed tomography pulmonary angiography (CTPA) also revealed the same findings. The baby was operated at 6 months of life (5.5 kg weight). She has been doing well postoperatively.


 

Discussion

APW is a rare congenital heart disease that accounts for < 1% of all congenital cardiac defects. When human embryos are approximately 6 mm in crown-rump length (CRL), the arterial pole of the heart begins septation with the formation of two opposing truncal cushions that soon enlarge and fuse to form the truncal septum dividing the truncus into aortic and pulmonary channels. More distally, the AP septum divides the truncoaortic sac after the sixth aortic arches have moved closer together and to the left and have aligned themselves with the pulmonary channel, and this partition is completed by approximately 9 mm CRL length.[1] The AP window develops due to the failure of fusion of these opposing conotruncal ridges that are responsible for the separation of the aorta and pulmonary trunks.[2]

Mori et al in 1978 proposed a classification of APW into three morphological types. Type 1 is the most common type, where there is a simple defect located between the aorta and the MPA, immediately above the sinuses of Valsalva. In type 2, the defect is located more distally between the ascending aorta and the pulmonary trunk, with extension into the origin of the right pulmonary artery (RPA). In type 3, there is an anomalous origin of the RPA from the ascending aorta.[3] [4] APW may occur as an isolated malformation, or in 25 to 35% of cases, it may be associated with other structural cardiac anomalies, the most common being arch abnormalities, particularly interrupted aortic arch and coarctation of the aorta. Unlike other conotruncal malformations, such as truncus arteriosus or interrupted aortic arch, the risk of associated chromosomal abnormalities in APW, including 22q11 deletion, is low.[5]

There have been very few case reports and limited case series on prenatal detection of the AP window. Less than 50 cases have been published so far.[6] [7]

In fetal echocardiography, the three-vessel view is the most important view to see the AP window defect. Also, the defect is well seen in any plane that is perpendicular to the defect.[5] In our case, the defect was seen in the three-vessel view as well as the circle sausage RVOT view. However, if there is any additional abnormality like TGA or DORV, then it cannot be seen on the three-vessel view. In that situation, sagittal views of the arches will demonstrate the defect.[5] Recently, a novel sign was published named as the red dot sign, which is typically seen in the middle of the RVOT within the MPA and it is suggested that this is due to turbulent blood flow across the AP window, which appears as a bright red dot on color Doppler images.[8] Similarly, our case also demonstrated a red dot sign in the circle sausage RVOT view across the AP window. Appropriate color settings, as described, along with the case discussion, should be followed; inappropriate color settings may lead to turbulent color flow, which may mimic the red dot sign. Another important sign is a high confluence V sign in the three-vessel trachea view instead of a normal ductus arteriosus.[9]

Fetal APW should be differentiated from persistent truncus arteriosus, the latter shows a single group of semilunar valves, while APW will demonstrate two groups of separate semilunar valves.[9]

We also need to rule out fetal Berry syndrome, which includes APW, interrupted aortic arch, aortic origin of RPA, and intact interventricular septum.[10] In our case, the origin of the RPA was normal and aortic arch was also normal, as shown in the sagittal arch view ([Fig. 3]). The association of APW with chromosomal abnormality and 22q11 microdeletion is low. However, the association between APW with Berry syndrome and trisomy 13 has been reported.[11] Berry syndrome patients need urgent surgery as critical pulmonary arterial hypertension appears early after birth due to massive pulmonary blood flow and circulating vasoconstrictors.[12]

In APW, increased pulmonary blood flow, congestive heart failure, and pulmonary hypertension are the major issues along with infective endocarditis. Postnatally, transthoracic echocardiography, CTPA, magnetic resonance imaging, or catheter angiography can be done for confirmation of diagnosis.[13] In our case, CTPA was done in the tertiary care center. Surgical correction should be done as early as possible regardless of the patient's age. Irreversible pulmonary hypertension with a right to left shunt is the only contraindication for surgery.[14]

Surgical correction in early infancy generally results in good long term outcomes. However, when associated with other congenital cardiac anomalies like interrupted aortic arch or coarctation of aorta, then there is increased risk of early reintervention.[15]


 

Conclusion

Prenatal diagnosis of APW is important for prenatal counseling as well as postnatal surgical management. Diagnosis can be made by careful evaluation of the three vessel trachea view and circle sausage RVOT view. The association with chromosomal abnormality is low. However, these can be associated with cardiac and extracardiac defects. Early surgical closure is indicated to prevent congestive heart failure and pulmonary hypertension.


 

 

Conflict of Interest

None declared.


Address for correspondence

Ruchi Gupta, MD
Department of Radiodiagnosis, Indira Gandhi Institute of Medical Sciences Patna
Patna 801503, Bihar
India   

Publication History

Article published online:
02 August 2025

© 2025. Society of Fetal Medicine. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/)

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Zoom
Fig. 1 Axial 4-chamber view of heart showing levocardia and normal cardiac axis (60 degrees).
Zoom
Fig. 2 The three-vessel trachea view shows the aortopulmonary (AP) window defect (white arrow) and high confluence of V sign.
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Fig. 3 Normal aortic arch seen.