Detection of airway ischaemic damage after lung transplantation by using autofluorescence imaging bronchoscopy

Airway complications related to ischaemia are a major cause of morbidity after lung transplantation. Early detection of airway ischaemia and optimal management of the anastomotic site could reduce the risk of airway complications. Autofluorescence imaging (AFI) bronchoscopy has been increasingly recognized as an effective technique for detecting abnormal mucosal thickening. The aim of this study was to investigate whether AFI bronchoscopy can facilitate the detection of airway ischaemic damage in lung transplant patients.

Twenty Landrace pigs were used to create a tracheal autotransplantation model. A four-ring length of trachea was excised and implanted orthotopically. The tracheal autograft was observed on postoperative days 0, 2, 4 and 7 with AFI bronchoscopy. The extent and origin of graft autofluorescence were examined using histology and measured according to fluorescence intensity.

The lesions on the tracheal autografts appeared as bright green fluorescence on AFI bronchoscopy. On confocal fluorescence microscopy, high-intensity green fluorescence was observed in the elastin fibre layer of the submucosa. The fluorescence intensity of elastin was significantly higher in the graft showing fluorescence than the graft that did not show fluorescence and that at the control site.

Bright green fluorescence was seen in an elastin fibre layer in the submucosa, which was likely a result of epithelial sloughing. There is a close relationship between the bright green fluorescence pattern observed using AFI bronchoscopy and airway ischaemic damage. We conclude that AFI bronchoscopy may detect airway ischaemic damage after lung transplantation.