Fetal diagnosis and management of pulmonary artery sling: A case series

Objective Pulmonary artery sling is a rare congenital anomaly accounting for 2% of all patients with vascular anomalies that cause airway obstruction. In the normal heart, the left (LPA) and right (RPA) pulmonary arteries arise in the intrapericardial space. However, in the pulmonary artery sling, the LPA trunk arises in the extrapericardial space from the posterior aspect of the mid RPA and courses posterior to the trachea causing tracheal compression and, at times, bronchial compression. While a full spectrum of congenital cardiac pathology can be identified before birth, only a few case reports document the prenatal diagnosis of an Left pulmonary artery sling (LPAS). Method We retrospectively identified all cases of prenatal LPAS from three Canadian fetal cardiology centers (2015–2022). Results Using the 3‐vessel‐tracheal view via fetal echocardiography (FE), four fetuses from three pregnancies demonstrated abnormal origin of the LPA from RPA and echogenic trachea. In one of two affected monochorionic twins coronal imaging demonstrated a significant narrowing of the large airways consistent with significant airway obstruction. Conclusion Prenatal detection of LPAS by FE is possible and should prompt an evaluation for airway obstruction in the coronal view. Investigating associated lesions and genetic testing are recommended for informed shared decision making. Key points What's already known about this topic? Left pulmonary artery sling (LPAS) is a rare congenital anomaly that may cause airway obstruction, which is a critical condition that may necessitate emergent postnatal management. What does this study add? The study highlights prenatal detection of LPAS, emphasizing the importance of comprehensive antenatal evaluation. The unique aspect of our study lies in the coronal imaging for identifying prenatal airway obstruction and subsequent management, an area that has not been covered in existing literature.