Effect of Endovascular Treatment Rate on Outcomes and Survival after Intact Abdominal Aortic Aneurysm Repair

Abstract

Introduction - The endovascular aortic repair (EVAR) rate in patients with abdominal aortic aneurysms (AAAs) varies country-to-country between 28–79% (1). Although EVAR has many advantages over conventional open aortic repair (OAR), such as lower in-hospital mortality (2), no long-term survival benefit has been shown for AAA patients who have undergone EVAR compared with OAR (3). However, the patient populations vary between clinical trials and even within registries. To overcome this potential bias, we investigated the EVAR rates and outcomes after AAA repair in four geographically adjacent populations with identical demographics in terms of age, sex, ethnicity and burden of cardiovascular risk factors (4). Methods - This retrospective multicenter study was based on prospectively collected registry data from an area of 815 000 inhabitants. The catchment area was divided into four health care districts (population A, B, C and D) with one central hospital in each district. Each hospital was responsible for the treatment of AAA patients of their respective population. OARs were performed in all four hospitals, while all EVARs were performed in one center. Each hospital decided independently which patients they would treat with OAR and whom to refer for EVAR. The study involved 532 consecutive patients with intact (non-ruptured) infrarenal or juxtarenal AAA treated with EVAR (n=329) or OAR (n=203) between 2010 and 2016. Total intact AAA repair rates and EVAR rates were calculated for each population. Major complications were registered (in-hospital mortality, rebleeding, surgical wound infection, major cardiac event, stroke, acute kidney failure, gastrointestinal complications and limb ischemia), and patients were monitored for mortality until March 2017. The population demographics were retrieved from a national statistic database. Results - The sex and the age distributions were the same between the populations. The populations ranged between 147 000–252 000 inhabitants. The intact AAA repair rates were 9.8, 8.9, 9.9 and 8.7 per 100 000 inhabitants/year for populations A, B, C and D, respectively. There were no significant differences in the mean age (73.6 ± 8.0 years) or the mean aortic diameter (62 ± 13 mm) between the study populations. Populations A and B had high EVAR rates (74% and 72%, respectively) whereas the EVAR rate was lower in populations C and D (50% and 38%, respectively) (P<0.001). The 30-day mortality rates were 2.4%, 2.6%, 3.9% and 1.0%, and complication rates were 17.7%, 12,7%, 15.1% and 11.5% for populations A, B, C and D, respectively. There were no statistically significant differences in 30-day mortality and complication rates, and neither in the long-term survival between the groups (Figure). The mean follow-up time was 3.3 ± 2.0 years. Conclusion - High EVAR rate had no measurable effect on the survival and outcomes in patients with intact AAA. In population D with the highest OAR rate, immediate outcomes were favourable, however, the differences did not reach statistical significance.