Mortality outcomes of ruptured abdominal aortic aneurysms and rural presentation

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

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 specialty care to quaternary referral centres. The association between travel distance by air ambulance and rAAA mortality in patients transferred as an emergency 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 an OSH for continued critical care were excluded. Patients were divided into near and far groups based on the 75th percentile of the straight line travel distance (> 72 miles) between hospitals. The primary outcome was 30 day mortality. Multivariable logistic regression was used to assess the association between distance and 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 the 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 use were also similar. Neither the observed (26.8% vs. 23.9%, p = .61) nor the adjusted odds ratio (0.70, 95% confidence interval 0.36 - 1.39, p = .32) 30 day mortality rate differed significantly between the 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.

Survival following abdominal aortic aneurysm repair in North Queensland is not associated with remoteness of place of residence

Objective

To assess whether survival and clinical events following elective abdominal aortic aneurysm (AAA) repair were associated with remoteness of residence in North Queensland, Australia.

Methods

This retrospective cohort study included participants undergoing elective AAA repair between February 2002 and April 2020 at two hospitals in Townsville, North Queensland, Australia. Outcomes were all-cause survival and AAA-related events, defined as requirement for repeat AAA repair or AAA-related mortality. Remoteness of participant’s place of residence was assessed by the Modified Monash Model classifications and estimated distance from the participants’ home to the tertiary vascular centre. Cox proportional hazard analysis examined the association of remoteness with outcome.

Results

The study included 526 participants undergoing elective repair by open (n = 204) or endovascular (n = 322) surgery. Fifty-four (10.2%) participants had a place of residence at a remote or very remote location. Participants' were followed for a median of 5.2 (inter-quartile range 2.5–8.3) years, during which time there were 252 (47.9%) deaths. Survival was not associated with either measure of remoteness. Fifty (9.5%) participants had at least one AAA-related event, including 30 (5.7%) that underwent at least one repeat AAA surgery and 23 (4.4%) that had AAA-related mortality. AAA-related events were more common in participants resident in the most remote areas (adjusted hazard ratio 2.83, 95% confidence intervals 1.40, 5.70) but not associated with distance from the participants’ residence to the tertiary vascular centre

Conclusions

The current study found that participants living in more remote locations were more likely to have AAA-related events but had no increased mortality following AAA surgery. The findings emphasize the need for careful follow-up after AAA surgery. Further studies are needed to examine the generalisability of the findings.