An outcomes-based grading scale for the evaluation of cerebral aneurysms treated with flow diversion.

OBJECT: Despite the popularity of flow-diverting stents for the treatment of cerebral aneurysms, there is no widely accepted scale for the characterization of results. We present an outcomes-based grading scale that considers factors related to failure of flow diversion.

METHODS: The grading scale was developed using the results from consecutive patients at two institutions who were treated with flow diversion for a cerebral aneurysm. The initial treatment results were graded on patient, aneurysm, and treatment characteristics. A 6-point grading scale was developed based on these data.

RESULTS: One hundred and seventy-one patients were included in the patient cohort. When compared by multivariate analysis with patients without residuals, patients with aneurysm residuals were found to be older (age ≥60 years, p=0.01, OR 1.17, 95% CI 1.03 to 1.33), to have larger aneurysms (size ≥15 mm, p<0.01, OR 1.38, 95% CI 1.17 to 1.62), to have aneurysms with associated side branches (p=0.02, OR 1.17, 95% CI 1.03 to 1.33), and to have a post-treatment Raymond score of 2 or 3 (p=0.01, OR 1.28, 95% CI 1.06 to 1.56). Using the Raymond score (1-3) as the foundation for the grading scale, additional points (0 or 1) were given for the other three identified factors, creating a 6-point scale. We found that patients with residual aneurysms had statistically higher final tabulated scores (p<0.01).

CONCLUSIONS: We propose a novel straightforward outcomes-based scale to characterize results after flow diversion treatment of cerebral aneurysms. This scale may provide the basis for the common reporting of results in future studies.