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E-051 Intracranial aneurysm classification scale optimized for treatment device indications and contraindications
  1. W Merritt,
  2. T Becker,
  3. A Ducruet
  1. Center for Bioengineering Innovation, Northern Arizona University, Flagstaff, AZ


Introduction Aneurysm classification is typically based upon midline-dome diameter (size) and occasionally utilizes other parameters such as midline-dome diameter to neck diameter ratio (d:n ratio) and neck diameter (figure 1). Size classifications are typically oriented around the aneurysm’s risk of rupture, and the classification ranges are often inconsistent between sources. While the current classification system still serves a significant role, we propose a more comprehensive and consistent classification system that considers multiple dimensions/parameters and allows surgeons, regulatory bodies, and medical device developers to quickly identify suitable treatment devices for patient-specific aneurysm dimensions and morphologies.

Materials and methods A meta-analysis of both intracranial aneurysm studies and papers outlining aneurysm classification systems provided data regarding aneurysm dimensions, correlation of aneurysm dimensions to treatment failure rates of endovascular devices, and the current state of aneurysm classification systems. This data was then used to create an intracranial aneurysm classification system that is optimized to help predict the success or failure of certain types of endovascular intracranial aneurysm treatments.

Results and discussion While there is a correlation between aneurysm size and the outcome of certain aneurysm treatment devices, there are other parameters that are equally as impactful on the treatment outcome, such as midline diameter (d), neck diameter (n), and the ratio between them (d:n ratio) (Figure 1). Neck diameter and d:n ratio both had significant effects on treatment outcome for certain devices, even though aneurysm size (dome height) is often the only dimension referenced.

Abstract E-051 Figure 1

An illustration depicting the different d:n ratio classifications that may be possible. From the illustration, it can be inferred how certain devices may perform poorly in certain dome to neck diameter ratio classifications.

Conclusions While aneurysm size can be an important indicator for both aneurysm rupture and treatment outcome, there are other parameters that also have a significant impact on treatment success. These additional parameters, such as midline diameter, neck diameter and the d:n ratio, should be carefully considered when choosing a device for treatment, developing a device, or approving devices into the market. The proposed classification system in this study has the potential to help close the research gap between the different classification systems that practitioners, developers, and regulators may apply to intracranial aneurysms.

Disclosures W. Merritt: 1; C; NIH, Northern Arizona University. T. Becker: 1; C; NIH, Northern Arizona University. A. Ducruet: 1; C; NIH, Northern Arizona University. 5; C; Barrow Neurological Institute.

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