Beyond the Neck: Device-Dependent Proximal Sealing After EVAR—A Propensity-Matched Comparison of AFX and Endurant

Abstract

Aim:

To evaluate how the guideline-defined target anticipated sealing zone (TASZ) translates into the real achieved sealing zone (RASZ), and whether this relationship is stent-graft-dependent.

Methods:

In a retrospective single-center study, 365 consecutive endovascular abdominal aortic aneurysm repairs (Endurant, n=267; AFX, n=98; 2011–2022) were reviewed. Preoperative and first postoperative computed tomography angiography (CTA) scans were evaluated with a previously reported centerline-driven approach. Target anticipated sealing zone and RASZ were systematically evaluated. After exclusion of patients with a TASZ shorter than 15 mm, propensity-score matching produced 75 device pairs. The primary study outcome was to evaluate the relationship between TASZ and RASZ and its dependence on stent-graft design. The neck/apposition ratio (RASZ/TASZ) was calculated to quantify the proportion of the available preoperative neck length effectively used for circumferential sealing. Linear regression assessed the independent effects of oversizing and device type on the neck-to-seal ratio.

Results:

After matching, AFX achieved longer RASZ than Endurant (median 34 vs 25 mm; p<0.001) and larger sealing surface (2355 vs 1862 mm², p<0.001). Compared to TASZ length, Endurant showed a median shortfall of −8 mm (IQR=−20.5 to +1 mm), whereas AFX exhibited a median surplus of +2 mm (IQR=−4.5 to +11 mm; p<0.001). Regression analysis confirmed that device type, neck slope, and oversizing are independent predictors of seal utilization. Type Ia endoleak incidence was <5% without inter-device difference.

Conclusions:

In this retrospective analysis, despite no difference in type Ia endoleak rate, achieved proximal sealing differed between devices, with AFX more often extending beyond the traditional neck and Endurant more often not covering the entire projected neck length.

Clinical Impact

This study highlights that guideline-defined neck length does not uniformly translate into achieved proximal sealing across different stent-graft technologies. Quantifying the achieved sealing zone on early postoperative CTA provides additional anatomical information beyond instructions for use-based neck metrics and may help to better characterize device-specific sealing behavior.