The Effect of Aneurysm Diameter on Perioperative Outcomes Following Complex Endovascular Repair.

Objectives: Endovascular aneurysm repair (EVAR) for large infrarenal abdominal aortic aneurysms (AAA) has been associated with worse outcomes compared to EVAR for smaller AAAs. Whether these findings apply to complex AAAs (cAAA) remains uncertain.

Methods: We identified all intact complex EVAR (cEVAR) from 2012-2024 in the Vascular Quality Initiative. cEVAR was defined as having a proximal extent between zones 6-9 and at least one side branch/fenestration/chimney/parallel grafting. Aneurysm size was defined as follows: large: >65 mm (males), >60 mm (females); medium: 55-65 mm (males), 50-60 mm (females); and small: <55 mm (males), <50 mm (females). We assessed perioperative death, any complication, and in-hospital reintervention using logistic regression and mid-term mortality using adjusted Kaplan-Meier methods and Cox regression. Medium-sized aneurysms were compared to large and small aneurysms.

Results: Of 3,426 patients, 22.6% had large, 60.4% medium, and 17.0% had small aneurysms. As compared to medium and small aneurysms, large aneurysms demonstrated higher rates of perioperative death (4.8% vs. 2.6% vs. 0.5%), any complication (33.3% vs. 23.6% vs. 19.4%), and in-hospital reintervention (6.2% vs. 4.0% vs. 2.6%) (all p<.05). Median follow-up was 445 days. One-year mortality rates were higher in large aneurysms (12.3% vs. 7.8% vs. 3.8%; p<.001). After adjustment, when compared with medium-sized aneurysms, large aneurysms were associated with a significantly higher risk of perioperative death (adjusted odds ratio [aOR], 1.73; 95% confidence interval [CI], [1.09-2.72]), any complication (aOR, 1.44; [1.18-1.76]), and mid-term mortality (adjusted hazard ratio [aHR], 1.50; [1.19-1.88]), but not in-hospital reintervention (aOR, 1.46; [0.99-2.13]). While small aneurysms, as compared with medium-sized aneurysms, did not demonstrate a difference in any complication (aOR, 0.87; [0.68-1.10]), in-hospital reintervention (aOR, 0.77; [0.42-1.33]), and mid-term mortality (aHR, 0.78; [0.57-1.08], they did demonstrate a lower risk of perioperative death (aOR, 0.26; [0.06-0.71]).

Conclusions: In cEVAR for cAAA, large aneurysms, compared with medium-sized aneurysms, were associated with higher rates of perioperative death, any complication, and mid-term mortality, with in-hospital reintervention trending toward a statistically significant higher risk. While these results align with expectations, they emphasize the importance of effectively managing patients with large cAAAs and highlight the need for future research to determine whether patients might benefit more from medical therapy or open repair.