Direct visualization of postoperative aortobronchial fistula on computed tomography

BACKGROUND Postoperative aortobronchial fistula(ABF)is a rare complication that can occur in 0.3%-5.0%of patients over an extended period of time after thoracic aortic surgery.Direct visualization of the fistula via imaging is rare.AIM To investigate the relationship between computed tomography(CT)findings and the clinical signs/symptoms of ABF after thoracic aortic surgery.METHODS Six patients(mean age 71 years,including 4 men and 2 women)with suspected ABF on CT(air around the graft)at our hospital were included in this retrospective study between January 2004 and September 2022.Chest CT findings included direct confirmation of ABF,peri-graft fluid,ring enhancement,dirty fat sign,atelectasis,pulmonary hemorrhage,and bronchodilation,and the clinical course were retrospectively reviewed.The proportion of each type of CT finding was calculated.RESULTS ABF detection after surgery was found to have a mean and median of 14 and 13 years,respectively.Initial signs and symptoms were asymptomatic in 4 patients,bloody sputum was found in 1 patient,and fever was present in 1 patient.The complications of ABF included graft infection in 2 patients and graft infection with hemoptysis in 2 patients.Of the 6 patients,3 survived,2 died,and 1 was lost to follow-up.The locations of the ABFs were as follows:1 in the ascending aorta;1 in the aortic arch;2 in the aortic arch leading to the descending aorta;and 2 in the descending aorta.ABFs were directly confirmed by CT in 4/6(67%)patients.Peri-graft dirty fat(4/6,67%)and peri-graft ring enhancement(3/6,50%)were associated with graft infection,endoleaks and pseudoaneurysms were associated with hemoptysis(2/6,33%).CONCLUSION Asymptomatic ABF after thoracic aortic surgery can be confirmed on chest CT.CT is useful for the diagnosis of ABF and its complications.