Predicting Outcomes for Cerebral Aneurysms Treated with Flow Diversion: A Comparison Between 4 Grading Scales

Abstract

Objective: Despite the development of 4 grading scales of angiographic outcome after flow diversion for cerebral aneurysms, none have been widely adopted in the neurosurgical literature, nor have any been validated in an independent dataset. We evaluated the reported grading scales for their ability to predict aneurysm occlusion at follow-up.

Methods: Four reported grading scales were applied in a retrospective analysis of our prospectively maintained institutional database of patients with intracranial aneurysms treated with flow-diverting stents. Analysis of patient factors, aneurysm factors, and outcomes was made to compare the grading scales' ability to predict aneurysm occlusion.

Results: Ninety-nine aneurysms in 90 patients treated at our institution between 2011 and 2018 were included in the analysis. Lower Flow-Diverting Stent Score (FDSS) scores were associated with higher rates of aneurysm occlusion at final follow-up (P=0.004). The OKM, Kamran-Byrne, and SMART scales scores were not associated with aneurysm occlusion at final follow-up even after adjustments for baseline differences. Area under the receiver operating characteristic curve for the FDSS was 0.675 (0.534-0.816).

Conclusions: Although the FDSS was the only reported grading scale that was significantly associated with occlusion at follow-up, its ability to predict occlusion fell below the typical level for widespread clinical utility. The high rate of eventual occlusion of most aneurysms after flow diversion likely limits the clinical utility of a grading score for this application.

Keywords: Aneurysm; Endovascular; Flow diversion; Outcomes.