Controversy persists regarding the optimal treatment for large abdominal aortic aneurysm (AAA), with the publications of the National Institute for Health and Care Excellence (NICE) guideline on 'Abdominal aortic aneurysm: diagnosis and management' (NG156) on March 19th 2020. The pendulum of opinion swings once more from endovascular to open surgical treatment. We report our experience over the last 15 years in treating consecutive AAA by open surgery.

A retrospective review of a prospectively collected vascular database of all patients undergoing infra-renal open abdominal aortic aneurysm repair (OR) repair from 2004 to 2019 at a high-volume aortic centre was performed. We excluded Patients with: missing preoperative and postoperative data; thoraco-abdominal aneurysm; mycotic aneurysm; aortic dissection; aorto-enteric fistula; endovascular aneurysm repair (EVAR); secondary OR with explant of EVAR. OR for elective and emergency (ruptured and symptomatic) outcomes included early morbidity and 30-day mortality, and long-term survival. Fisher's exact test was used for univariate analyses, Kaplan-Meier analysis and log-rank or Wilcoxon tests were used to compare survival between both different postoperative major complications and the type of repair. A P-value of <0.05 from two-sided tests was considered statistically significant.

There were 1017 patients who underwent OR between 2004-2019, on application of our inclusion-criteria 980 patients formed our cohort for analysis (81.2% male) with a mean age 73.6±7.8 years treated by OR for AAA. 672 were elective and 308 were emergency (for ruptured or symptomatic aneurysms). In all cases a transabdominal approach was performed. Median aneurysm size at the time of repair was 61 mm in the open repair Elective AAA group (IQR, 12 mm) and 78mm in the Emergency RAAA group (IQR, 25mm). Patients in the elective group were significantly younger (p=0.0001), with a higher proportion of male patients (p=0.0083) and hypertension (p=0.01). There was a significantly higher proportion of American Society of Anaesthesiologists (ASA) class IV and V in the emergency group than the elective group p<0.0001. Median length of overall in hospital stay was 10 ± 19.6 days, for elective repair it was 9 days and emergency repair was 15 days. 36.6% of elective patients were recovered directly on the ward post operatively, the median LOS in critical care for elective repair was 1 day (range 0-71 days) and for emergency repair was 4 days (range 0-70days). Overall 30-day mortality was 11.3%, elective 30-day mortality was 2.5%, and emergency 30-day mortality was 29.9%. 30-day reintervention rate was 9.7%, (elective 7.0%, emergency 15.9%). The reasons for reintervention are outlined in Table 1. Survival at 1000 days for elective repair was 72% v 46.7% for emergency and at 2000 days was 43.4% for elective v 25% for emergency. Fig 1. There was no significant difference between the type of open repair performed and survival for either elective or emergency OR AAA. Fig 1.

Our data confirm that open surgery for AAA can be performed in large volume centres quite safely, with results comparable to the major Randomised Clinical Trials (RCTs). Female patients were significantly more likely to present as an emergency (p=0.008), which may be reflective of the success of the current screening paradigm in the United Kingdom. Elective and Emergency surgery does affect early 30-day mortality but does not influence long-term outcomes. Open surgery may still be considered the standard in the management of AAA.