Silicone Airway Stent Placement in an Immunocompromised Pediatric Heart Transplant Patient With Bronchomalacia and Co-morbid Mycobacterium Abscessus

Abstract Introduction: Historically, the use of bronchial airway stents has been limited within pediatrics. In adults, airway stents serve to maintain airway patency in both intrinsic and extrinsic disease, with most stents placed for malignant disease. In adults with tracheobronchomalacia, a trial of silicone stent placement is often helpful to identify patients that may be candidates for tracheobronchoplasty. Similarly, airway stenting for remodeling of severe bronchomalacia may be an important bridge for pediatric patients with airway stenosis or severe bronchomalacia without the surgical risks of airway bronchopexy. We present the case of a pediatric heart transplant patient whose lung disease secondary to tracheobronchomalacia improved following bronchial stent placement.Case Report: A 12-year-old female with Noonan's Syndrome underwent a heart transplant due to dilated cardiomyopathy with end stage heart failure two years ago. She had comorbid congenital tracheobronchomalacia and approximately one year of persistent productive cough and decrease in lung function despite multiple courses of antibiotics. Chest CT showed marked left lower lobe bronchial wall thickening with surrounding tree-in-bud and groundglass opacities, prompting consideration of opportunistic infection in the setting of immunosuppression. Bronchoscopy showed distal tracheal and left mainstem bronchial narrowing, the latter measuring 2-3 mm. She began an intensive airway clearance regimen with limited improvement. We placed a 9 x 40mm silicone stent in the left mainstem bronchus via rigid bronchoscopy. Surveillance flexible bronchoscopy with bronchoalveolar lavage one month after stent placement identified Mycobacterium abscessus complex from the left lower lobe. Repeat chest CT 3 months after stent placement demonstrated improved aeration of the left lung, fewer filling defects throughout the left bronchial tree, and minimal bronchiectasis. Now, four months after stent placement, she is undergoing targeted antimicrobial treatment for M. abscessus. The silicone stent remains patent and in place without complication.Discussion: Airway stent placement in pediatrics is both safe and effective in appropriate patients. There is limited evidence to suggest the benefit of surgical bronchopexy in children with severe bronchomalacia. A removable silicone stent may be an effective treatment strategy to lead to the desired result of airway remodeling, particularly in those patients who are immunosuppressed or when perioperative risk precludes surgical intervention. In our case, stenting of the airway allowed for effective airway clearance and resulted in parenchymal improvement. We will continue surveillance bronchoscopy every 2 months with a plan for removal at approximately 6 months if M. abscessus has successfully cleared