Aortopulmonary window and right aortic arch in a fetus

Aortopulmonary window (APW) is a rare congenital cardiac abnormality in which there is a failure of formation of the separate and adjacent walls of the intrapericardial arterial trunks, with persistence of the aortopulmonary foramen [1]. It occurs either in isolation or in combination with other cardiac anomalies such as transposition of the great arteries, tetralogy of Fallot, or interrupted aortic arch [2–4]. In this paper we focus on the first description of a prenatal diagnosis of APW in association with right aortic arch and perimembranous ventricular septal defect (Figure 1). Nuchal translucency was normal and risk for aneuploidies was low at the first trimester. There were no extracardiac anomalies found on subsequent ultrasound scans. An abnormal appearance of the three vessel and tracheal view was noted during a growth scan at 32 weeks of gestation. The diagnosis of APW was made on fetal echocardiography and confirmed on fetal cardiac magnetic resonance imaging (Figures 1C and 2), which is adjunct to our clinical practice [5].
The baby was born at term, no dysmorphic features were present, and the array CGH was normal. Postnatally the cardiac diagnosis was confirmed by transthoracic echocardiogram, and no further imaging was required. The neonate developed symptoms of congestive heart failure and was commenced on diuretics at two weeks of age. Successful cardiac surgery was accomplished at three weeks of age, comprising closure of the ventricular septal defect and the large, akin type II (distal) [6], aortopulmonary window (Figure 3) with Gore-Tex patches. Two years later the infant is thriving with no ongoing cardiac symptoms.
Aortopulmonary window is a challenging diagnosis to make on echocardiography pre- and postnatally. Our described case also has a right aortic arch, which is an unusual combination and has not been demonstrated prenatally. The three-vessel and tracheal view is a key view for prenatal ultrasound screening. However, care should be taken to ascertain that the heart and the “V” sign are on the ipsilateral side to avoid overlooking the combination of right aortic arch and right arterial duct.
In this case (Figure 1) the three-vessel and tracheal view shows both the pulmonary artery and the transverse aortic arch on the right side of the trachea. A large well-demarcated communication between the pulmonary artery trunk and the proximal aorta is visualised. There is no arterial duct seen on either the left or the right side joining the descending aorta.
Conversely, a right arterial duct would arise from the posterosuperior aspect of the junction of the pulmonary trunk and right pulmonary artery and course posteriorly, on the right of the trachea, joining the junction of the right aortic arch and descending aorta distal and opposite to the origin of the right subclavian artery.
Such a diagnosis is unlikely to have cardiorespiratory implications after birth. Contrary to this, an APW will result in congestive cardiac failure and may lead to irreversible pulmonary vascular disease if diagnosed late. Thus, prenatal diagnosis of APW would lead to timely postnatal management with potentially good long-term outcome.

Compliance with ethical standards

Sources of funding: Development of fetal cardiac magnetic resonance imaging was supported by the Wellcome/Engineering and Physical Sciences Research Council Centre for Medical Engineering (WT 203148/Z/16/Z) and the Wellcome Trust Innovative Engineering for Health Award (102431). The research was funded by the National Institute for Health Research (NIHR) Biomedical Research Centre based at Guy’s and St Thomas’ NHS Foundation Trust and King’s College London, and it was supported by the NIHR Clinical Research Facility at Guy’s and St Thomas’. The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR, or the Department of Health.

Conflict of interest

The authors declare no conflict of interest.

REFERENCES

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Division of work:
Vita Zidere (ORCID: 0000-0001-7505-6621): research concept and design, collection and/or assembly of data, data analysis and interpretation, writing the article, critical revision of the article, final approval of the article
Trisha Vigneswaran (ORCID: 0000-0002-4084-4203): research concept and design, collection and/or assembly of data, data analysis and interpretation, writing the article, critical revision of the article, final approval of the article
David F.A. Lloyd (ORCID iD: 0000-0003-1759-6106): data analysis and interpretation, critical revision of the article, final approval of the article
Meekai To (ORCID: 0000-0001-6568-9193): collection and/or assembly of data, critical revision of the article, final approval of the article
Kuberan Pushparajah (ORCID: 0000-0003-1541-1155): collection and/or assembly of data, data analysis and interpretation, critical revision of the article, final approval of article
Conal Austin (ORCID: 0000-0003-4417-7310): collection and/or assembly of data, critical revision of the article, final approval of the article