Thermal Ablation (Laser vs. Argon Plasma Coagulation) for the Treatment of Excessive Dynamic Airway Collapse: An in vivo Study in Bama Miniature Pigs

INTRODUCTION: Excessive dynamic airway collapse (EDAC) is a condition characterized by excessive narrowing of the trachea and bronchi during exhalation, leading to respiratory symptoms. While bronchoscopic tracheobronchoplasty using laser-based thermal ablation has been reported in clinical practice, the lack of preclinical studies, including animal models, limits a comprehensive understanding of its safety and efficacy. This study compares laser and argon plasma coagulation (APC) thermal ablation in a Bama miniature pig model to assess their effects on airway histopathology and healing. METHODS: Twelve Bama miniature pigs underwent noncontact laser ablation and precise APC ablation of the membranous trachea via flexible bronchoscopy under different parameter settings. The animals were euthanized either immediately post-procedure or at 28 days. Histopathological changes were assessed using HE and Masson's trichrome staining. The remaining animals were closely monitored for 28 days postoperatively for infection, hemoptysis, and respiratory distress. Bronchoscopic evaluations were conducted on days 7, 14, 21, and 28 to assess tracheal healing. RESULTS: All 12 procedures were successfully completed without major intraoperative complications. Acute histopathological changes included necrosis and sloughing of the mucosal and submucosal layers. Between postoperative days 7 and 14, varying degrees of cough and dyspnea were observed. By day 28, histopathological analysis showed significant collagen fiber proliferation in the submucosal layer, with collagen layer thickness directly proportional to APC power and inversely proportional to laser power. CONCLUSION: When the injury depth is limited to the submucosal layer of the tracheal membranous part by setting reasonable technical parameters, laser and precise APC can induce fibrous tissue hyperplasia and collagen deposition. However, precise APC is safer and more feasible, and further research is still needed to improve the surgical parameters and evaluate long-term clinical results.