Preoperative neck growth and size are associated with type 1a endoleak after endovascular aneurysm repair

Type 1a endoleak (T1a) is seen in up to 15% of endovascular aortic aneurysm repair (EVAR) within instructions for use (IFU). Involvement of neck by abdominal aortic aneurysm (AAA) pathology may increase the risk of T1a, although current methods based on diameter/volume, may miss slow/submaximal preoperative growth in the neck. Vascular deformation mapping (VDM) is an emerging method for quantifying aortic wall growth in three-dimensional (3D) with submillimeter accuracy. We sought to determine the association of pre-EVAR neck growth and size with T1a using VDM.

We identified patients with infrarenal AAA who underwent EVAR between 2010 and 2024. Patients were included if they had ≥2 preoperative computed tomography angiograms (CTAs) completed ≥6 months apart with the last CTA being ≤3 months of EVAR. Patients with noncontrast computed tomography scans, off-IFU, and those treated with prophylactic endoanchors were excluded. Patient sex and device type were collected. AAA neck diameters and volumes were measured from both preoperative CTAs using PRAEVAorta (Nurea) and changes over time were calculated. VDM, which involves a multistep deformable image registration, was used to quantify 3D growth (3D defined as degree of deformation in the direction normal/perpendicular to the aortic wall) and 3D size (defined by local centerline radius) of the aneurysm neck. Statistical shape modeling was used to compare mean 3D growth and 3D size of the neck and four neck segments (anterior, posterior, left lateral, and right lateral) between patients with and without T1a.

The cohort included 97 patients (90.7% male; average age, 73.0 ± 9.6 years). Twenty-one patients (21.6%) developed T1a. T1a endoleak was not associated with patient demographics, neck diameter, neck length, neck volume, or changes in neck diameter and/or volume (P > .05, for all). However, patients with T1a had larger 3D growth in the aneurysm neck (3.3 ± 0.8 vs 2.4 ± 0.6 mm/year; P < .001) and across all neck segments (P < .001, for all). Receiver-operating characteristic analysis identified a mean neck 3D growth ≥2.7 mm/year as a predictor of T1a (area under the curve, 0.78; sensitivity, 0.81; specificity, 0.76). Neck 3D size was larger in T1a patients compared with controls (12.5 ± 0.4 vs 11.5 ± 0.6 mm; P < .001) and across all neck segments (P < .001, for all). Receiver-operating characteristic analysis identified an optimal cut-point for neck 3D size of 11.9 mm as a predictor of T1a (area under the curve, 0.85; sensitivity, 86%; specificity, 84%).

Preoperative 3D growth and 3D size of the aneurysm neck are strong predictors of T1a, despite devices being on-IFU. VDM can provide important information about aneurysm growth that is not captured via current standard methods. Preoperative aneurysm neck growth/size should be considered for optimal EVAR planning.