Tracheal development after left pulmonary artery reimplantation: an individual study

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 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.

Pulmonary artery sling: An overview

Pulmonary artery sling is a rare childhood vascular tracheobronchial compression syndrome that is frequently associated with tracheal stenosis. Consequently, neonates or infants may present with critical airway obstruction if there is long segment airway narrowing and complete rings. Rapid diagnosis of this cardiac vascular malformation and evaluation of the extent and severity of airway involvement is essential to plan surgery, typically a slide tracheoplasty to relieve critical airway obstruction. Long term outcome can be excellent following surgical repair of the stenosed airway and reimplantation of the left pulmonary artery. In this review we focus on the embryology, diagnostic workup, airway investigations and management for this rare but challenging congenital condition.

A Delayed Anatomic Diagnosis and Management Challenge in an Initially Asymptomatic Infant With Type II Pulmonary Artery Sling: A Case Report

Pulmonary artery sling (PAS) is a rare but fatal malformation. Patients with PAS tend to develop obstructive symptoms in few weeks of life. Conversely, some patients may be otherwise mild or asymptomatic in their early life. Currently, no consensus on the intervention timing and treatment strategy for asymptomatic and mild cases has been reached. Moreover, the extent of tracheal stenosis is another determining factor for the choice of intervention timing since clinical symptoms might not correspond well with the degree of stenosis. Lack of comprehensive assessment of entire airways confer underestimation of disease severity and in turn improper choice of treatment regimens and poor outcomes. Herein, we described an infantile case of PAS, who was scheduled initially for periodic outpatient follow-up on account of the absence of symptoms and inadequate imaging assessment at diagnosis. The patient developed recurrent wheezing and progressive respiratory distress at 7 months of age. After left pulmonary artery (LPA) reimplantation without tracheal intervention, bronchoscopy was performed due to failure to wean from mechanical ventilation, which demonstrated complete tracheal cartilage rings, a long segment tracheal stenosis, a low tracheal bifurcation at T6, and the absence of a separate right middle lobe bronchus. The patient was finally diagnosed with type IIb PAS and extubated successfully following conservative treatment. Miserably, neurological sequelae were devastating, leading to poor outcomes. Comprehensive airway evaluation using bronchoscopy is substantial to early identification of all components responsible for airway compromise in PAS anatomic subtypes. Considering severe concomitant maldevelopment of the bronchial tree in children with type IIb PAS, early and complete correction by surgery might decrease perioperative morbidities and mortalities of these patients.