The impact of pre-treatment aneurysm angulation. What happens with WEB devices at follow-up?

Background: WEB shape modification has been analyzed in relation to the aneurysm occlusion outcome and techniques have been presented with one-dimensional measurements of the device to quantify the change after implantation. In this work, we present an analysis of pre-treatment vascular morphology and hemodynamics of cases treated with WEB devices, which were three-dimensionally quantified in morphology and position to detect modifications.

Methods: Seventeen WEB-treated aneurysms with pre-treatment, post-treatment and follow-up 3D flat-panel CT were included. Three-dimensional measurements of the WEB morphology and position were made at post-treatment and at follow-up. Differences between acquisitions of all measured variables were statistically evaluated (Wilcoxon signed-rank paired test, P-value = 0.05). Pre-treatment aneurysm angles were three-dimensionally measured and CFD simulations were performed to evaluate the influence of flow on WEB changes.

Results: WEB height and diameter presented statistically significant changes. Modification of the angle between the WEB axis and parent artery was significantly higher in the group with WEB shape modification (Mann-Whitney U test, P < 0.05). In this group, the median pre-treatment aneurysm angle was smaller than in the group without shape modification (8.16° vs. 13.14°, P = 0.06). Inflow ratio was higher in the WEB shape modification group.

Conclusions: An association between the magnitude of morphological changes of the WEB with the direction of its axis within the aneurysm was found. The analysis of pre-treatment morphological and hemodynamic conditions would allow the detection of aneurysm cases in which the WEB will undergo a more pronounced modification.