Hostile Aortic Neck Anatomy Increases Risk of Intraoperative Type I Endoleak After Endovascular Aneurysm Repair: Analysis of the Vascular Quality Initiative

Introduction: Hostile neck anatomy (HNA) remains a major challenge to the technical success and durability of endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA). This study investigates aortic neck characteristics and the risk of intraoperative type I endoleak (EL-I) following EVAR. Methods: All patients who underwent EVAR between 2015 and 2024 were identified from the Society for Vascular Surgery Vascular Quality Initiative database. Patients with a history of arterial bypass or aneurysm repair, those with iliac aneurysm, deemed unfit for open repair, or who required conversion to open repair were excluded. The study cohort was stratified based on the presence of HNA, defined as neck angle >60°, neck diameter >28 mm, or neck length <10 mm. The primary outcomes were intraoperative EL-I and 30-d mortality. Univariate analysis was conducted using two-sample t-tests and Chi-squared tests. Multivariable logistic regression was utilized to identify independent associations between individual hostile neck characteristics and intraoperative EL-I. Results: Among 15,600 patients who underwent EVAR, 2768 (17.7%) were found to have HNA. Patients with HNA were older (74.4 versus 73.2 y, P < 0.001) and more frequently female (23.7% versus 19.5%, P < 0.001), with no significant differences in racial distribution. The incidence of intraoperative EL-I was significantly increased (5.1% versus 2.9%, P < 0.001), and the 30-d mortality rate was low overall but modestly higher in the HNA group (0.9% versus 0.5%, P = 0.004). Multivariable logistic regression demonstrated that increasing aortic neck angulation showed a strong graded association with EL-I. Compared to patients with neck angle <45°, those with neck angles 45-60, 61-75, 76-90 and >90° had adjusted odds ratios (AORs) that increased progressively: 1.44 (1.14-1.84, P =<0.01), 1.75 (1.17-2.62, P < 0.01), 2.42 (1.53-3.80, P < 0.01), and 2.65 (1.54-4.50, P < 0.01), respectively. Longer neck length was associated with reduced odds of EL-I (AOR 0.78 per cm increase, 95% confidence interval [0.72-0.85], P < 0.01). Aortic neck diameter was not found to be associated with EL-I (AOR 1.01, 95% confidence interval [0.97, 1.04] P = 0.65). Conclusions: HNA is associated with an increased risk of intraoperative EL-I following EVAR, with severe neck angulation emerging as the dominant anatomic predictor in a clear dose-response relationship. These findings support the need for refined anatomic risk stratification beyond binary instructions-for-use definitions and highlight the importance of individualized preoperative with consideration of adjunctive techniques or alternative repair strategies in patients with hostile aortic necks.