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

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.

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.

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.

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.