Influence of severe neck angulation on hemodynamic and clinical outcomes following endovascular aneurysm repair: a hemodynamic analysis and a retrospective cohort study.

Background: For patients with severe neck angulation (SNA), hemodynamic and clinical outcomes following endovascular aneurysm repair (EVAR) are still unclear. This study aimed to explore the influence of SNA on hemodynamic and clinical outcomes following EVAR.

Methods: This study included a hemodynamic analysis and a retrospective cohort study from West China Hospital of Sichuan University between January 2011 and December 2020. The Cox regression model, inverse probability of treatment weighting (IPTW) analysis, sensitivity analysis, and subgroup analysis were applied. Primary outcome was type IA endoleak (T1AEL).

Results: In this hemodynamic analysis, nine non-severe neck angulation (nSNA) and 16 SNA idealized models were constructed. We found a significant difference in drag force between SNA and nSNA models (7.016 ± 2.579 N vs. 4.283 ± 1.460 N, P = 0.008), and proximal neck angles were significantly associated with the magnitude of drag force (F = 0.082 × α-0.006 × β + 2.818, α: 95% confidence interval [CI] 0.070-0.094; P = 0.001; β: 95% CI -0.019 to 0.007; P = 0.319). In our cohort study, 514 nSNA patients (71.5 ± 8.5 years; 459 males) and 208 SNA patients (72.5 ± 7.8 years; 135 males) were included, with a median follow-up duration of 34 months (16-63 months). All baseline characteristics were well balanced after IPTW matching. We found that SNA was associated with a significant risk of adverse limb event (hazard ratio [HR] 2.18, 95% CI 1.09-3.12), yet was not associated with T1AEL, overall survival, or reintervention. In patients without proximal or distal additional procedures (DAP), subgroup analyses suggested a significant risk of T1AEL (Proximal: HR 5.25, 95% CI 1.51-18.23; Distal: HR 5.07, 95% CI 1.60-16.07) and adverse limb event (Proximal: HR 2.27, 95% CI 1.01-5.07; Distal: HR 2.91, 95% CI 1.30-6.54) in SNA patients. However, no noticeable difference was observed in patients with proximal or DAP.

Conclusions: SNA has a critical influence on hemodynamic and clinical outcomes following EVAR. Appropriate additional procedures may be of great benefit to SNA patients.