EVOLVING PRACTICE TRENDS AND SHORT TERM OUTCOMES OF OCTOGENARIANS UNDERGOING COMPLEX ABDOMINAL AORTIC ANEURYSM REPAIR IN PORTUGAL: A MULTICENTRE, REGISTRY BASED COHORT STUDY.

OBJECTIVE: The prevalence of abdominal aortic aneurysms (AAA) has increased among older adults. Complex AAAs (cAAA) involving the renovisceral segment pose substantial treatment challenges and require individualised strategies. For elders, evidence to support the best strategy is scarce. This multicentre, registry based, observational cohort study aimed to assess short term outcomes after cAAA repair in patients aged ≥ 80 years, using the Portuguese National Registry of Vascular Procedures. METHODS: Patients with intact cAAA (juxtarenal, pararenal, or complex infrarenal necks outside instructions for use for endovascular aneurysm repair [EVAR]) treated by open repair, fenestrated/branched EVAR (F/BEVAR) or EVAR (proximal neck adjuncts or off label standard EVAR) were included. The primary endpoint was major adverse events (MAEs). Secondary endpoints were textbook outcomes, mortality, failure to rescue, and practice trends. Inverse probability weighting was used to assess outcomes. RESULTS: Among 418 cAAA repairs, 21.5% were octogenarians (OG). They were more often treated by endovascular means (84.4% OG vs. 65.2% non-octogenarians [NOG]; adjusted odds ratio [aOR] 3.12 [95% confidence interval [CI] 1.45 - 6.72]). By 2024, F/BEVAR emerged as the preferred technique in OG (54.5%). Thirty day MAEs and mortality were significantly increased in OG (21.1% vs. 14.0% NOG, aOR 2.88, 95% CI 1.37 - 6.07 and 8.9% vs. 3.0% NOG, aOR 8.80, 95% CI 2.54 - 30.52). Textbook outcomes were less frequent in OG (47.8% vs. 64.0% NOG, aOR 0.37, 95% CI 0.21 - 0.66). Failure to rescue was comparable across age groups. Within octogenarians, open surgical repair (vs. endovascular repair) was associated with increased MAEs. One year survival was lower in OG (65.2% vs. 88.2% NOG, octogenarian aOR for 1 year mortality 6.85, 95% CI 2.90 - 16.15). CONCLUSION: Octogenarians represent a relevant proportion of cAAAs treated in Portugal. Practice favours endovascular repair, with a shift towards F/BEVAR. Despite minimally invasive approaches, octogenarians remain at higher risk of peri-operative complications. The excess peri-operative morbidity and 1 year mortality support concerns regarding patient selection and expected benefit in elders.