1255. Using Both Aneurysm Coil Packing Density and Raymond-Roy Classification Increases Prediction Rate for Aneurysm Recanalization

Authors: Bart Thaci, MD; Kristin Nosova, MD; Brian Dahlin, MD; Ben Waldau, MD (Sacramento, CA)

Introduction: Predicting recanalization after aneurysm coiling would individualize follow-up intervals and postoperative patient discussions. Different groups have used coil packing density or radiological classificationto predict such recurrences. There are no data on whether a combination of such methods can provide a better prediction tool. Methods: We retrospectively reviewed our cases completed between 2011-2014. All patients with preoperative CTA brain and at least 6 months follow-up digital subtracted angiograms were included. Two senior authors performed treatments and supervised grading of the aneurysm coiling and calculation of coil packing density. ANOVA fixed effects model was used to evaluate association between Raymond-Roy class (RRC) and coiling density. Logistic regression model was used to estimate the probability of need for recanalization as a function of RRC. Results: Of 42 patients: 13 achieved RRC 1 coiling, 16 patients with RRC2 and 13 patients with RRC3. Coil packing ranged from 4.2% to 33.8%. In ANOVA analysis, compared to RCC3, RRC1 and 2 were weakly associated with higher coil packing density (coefficients: 0.05, 0.06 and p-values .038 and .048, respectively). We found that 0% of RRC1 patients required retreatment for recanalization, compared to 25% of patients with RRC2 and 69% of patients with RRC3. Within RRC2 group, aneurysms that did not recanalize had apacking density of 19% vs 21% for the group that recanalized and required retreatment (non-significant). Among RRC3 patients, aneurysms that did not recanalize had an average packing density of 16% vs. 13%, non-significant. Interestingly though in this group, 3/4 aneurysms that did not recanalize had coiling density >18%, while all that recanalized had 16.5% or less. Conclusion: There is a correlation between RRC and packing density for aneurysm coil embolizations. For patients with RRC3 coiled aneurysms, a packing density of 16.5% or less always led to retreatment.