Clinical and imaging features of pulmonary artery sling in infants without significant hemodynamic changes

Pulmonary artery sling (PAS) is a rare congenital heart anomaly and may cause unexplained respiratory symptoms in infants. Since the non-specific respiratory symptoms of PAS may lead to misdiagnosis, the aim of this study was to clarify the clinical and imaging features of this disease for timely diagnosis and treatment.

Clinical histories, physical examinations and imaging studies were retrospectively evaluated in nine infants with PAS. Chest X-ray, echocardiography and contrast-enhanced computed tomography (CT) with 3-dimensional reconstructions were performed in all patients and three of them received surgical treatment.

Nine cases included six males and three females with a mean age of (4.3 ± 2.8) months ranging from 2 to 11 months old. All patients had respiratory symptoms including recurrent cough, stridor and wheezing. The onset of symptoms was within 3 months in all cases and three children had symptoms only a few days after birth. The chest X-ray showed pneumonia in all cases. Contrast-enhanced CT showed the tracheal compression at different lengths in every case. The echocardiograph findings of PAS were anomalous origins of the left pulmonary artery from the posterior aspect of the right pulmonary artery. Of the 9 cases, 8 cases were diagnosed correctly by echocardiography. Of the complicated abnormalities, there were one with secundum atrial septal defect, one with patent foramen ovale and three with persistent left superior vena cava. None of them were complicated with significant blood dynamic changes.

Infants with recurrent respiratory symptoms such as chronic cough, stridor and wheezing, should be examined for the possible presence of congenital pulmonary artery sling. As a noninvasive technique, echocardiography is very helpful and should be the first-choice modality for the diagnosis of pulmonary artery sling. Contrast-enhanced CT, clearly demonstrating the anatomy of pulmonary artery sling and the position and extent of trachea compression, is necessary for the final diagnosis and pre-operation evaluation.