Incidence of congenital tracheal stenosis in left pulmonary artery sling diagnosed by bronchoscopy

Purpose: Congenital tracheal stenosis (CTS) has been reported to occur in 50–65% of cases of left pulmonary artery sling (LPAS), but the exact incidence rate is unknown. This study aimed to determine the actual rate by using bronchoscopy and to elucidate morphological features in computed tomography (CT) diagnosis. Methods: We performed a single institutional retrospective review of all patients with LPAS between January 2010 and March 2022. The percentage of complete tracheal rings in patients with LPAS was evaluated using bronchoscopy. The anteroposterior/lateral diameter ratios at the smallest and largest diameters of each CTS patient’s trachea were measured on CT. The Wilcoxon signed-rank test was used to analyze the differences between the two parts. Results: Fifty-two patients with LPAS were enrolled. All patients had complete tracheal rings on bronchoscopy. CT analysis of 32 patients with CTS was performed. The median anteroposterior/lateral diameter ratio at the smallest diameter was 1.05 (interquartile range [IQR], 0.95–1.15); the median ratio at the largest diameter was 0.94 (IQR, 0.89–0.99). There was a significant difference between the two parts (p = 0.013). Conclusion: CTS might be universally associated with LPAS. The circular tracheal cross-section on CT might imply the existence of a complete tracheal ring.