Angiographic results of aneurysms treated with Woven EndoBridge (WEB) devices or coils: an inter- and intra-observer reliability study.

Background: Angiographic results are commonly used to evaluate and compare the treatment of aneurysms. We sought to determine and compare the reliability and clinical implications of a commonly used 3-point angiographic outcome scale for aneurysms treated with WEB or endovascular coils.

Methods: An electronic portfolio of 60 aneurysms (30 treated with WEB devices and 30 with coils) was evaluated by 32 raters of various training backgrounds, who were asked to grade angiographic results and provide management recommendations (delayed follow-up, close follow-up, or re-treatment). Twenty-five raters performed a second evaluation of permuted cases at least a month later. Agreement was analyzed with Gwet's AC2 (κ) reliability coefficients and the relationship between angiographic grade and management recommendation using Cramer's V.

Results: Inter-rater agreement was substantial for occlusion grade (κ = 0.78; 95%CI: 0.74-0.82) and management decision (κ = 0.79; 95%CI: 0.74-0.84). Agreement was substantial and similar for angiographic results of WEB-treated (κ = 0.78; 95%CI: 0.79-0.85) and coiled aneurysms (κ = 0.79; 95%CI: 0.74-0.83). Inter-rater agreement on management decisions was substantial for both WEB-treated aneurysms (κ = 0.79; 95%CI: 0.73-0.85) and coiled aneurysms (κ = 0.79; 95%CI: 0.73-0.85). Mean intra-rater agreement was substantial or almost perfect. There was strong correlation between angiographic grade and management recommendation (mean Cramer's V = 0.77, SD: 0.12). The meaning of each category of the scale in terms of further management was the same, whether treatment was with WEB or coils.

Conclusion: A commonly used 3-point scale was shown to be a reliable tool to compare the results of aneurysms treated with WEB devices or endovascular coils.