The Role of Integrated Air Transport System in Managing Abdominal Aortic Aneurysm Rupture Patients.

OBJECTIVE: Ruptured abdominal aortic aneurysms (rAAAs) are highly morbid emergencies. Not all hospitals are equipped to repair them, and an air ambulance network may aid in regionalising speciality care to quaternary referral centres. The association of travel distance by air ambulance on rAAA mortality in patients transferred emergently for repair was examined.

METHODS: A retrospective review of institutional data. Adults with rAAA (2002 - 2019) transferred from an outside hospital (OSH) to a single quaternary referral centre for repair via air ambulance were identified. Patients who arrived via ground transport or post-repair at OSH for continued critical care were excluded. Patients were divided into "near" and "far" groups based on the 75th percentile of straight line travel distance (> 72 miles) between hospitals. The primary outcome was 30 day mortality. Multivariate logistic regression was used to assess the association of distance with mortality after adjusting for age, sex, race, cardiovascular comorbidities, and repair type.

RESULTS: A total of 290 patients with rAAA were transported a median distance of 40.4 miles (interquartile range 25.5, 72.7) with 215 (74.1%) near and 75 (25.9%) far patients. Both near and far groups had similar ages, sex, and race. There was no difference in pre-operative loss of consciousness, intubation, or cardiac arrest between groups. Endovascular aneurysm repair utilisation and intra-operative aortic occlusion balloon usage were also similar. Both observed (26.8% vs. 23.9%, p = .61) and adjusted odd ratio (0.70, 95% confidence interval 0.36 - 1.39, p = .32) 30 day mortality did not differ significantly between near and far groups.

CONCLUSION: Increasing distance travelled during transfer by air ambulance was not associated with worse outcomes in patients with rAAA. The findings support the regionalisation of rAAA repair to large quaternary centres via an integrated and robust air ambulance network.