Comparison of Ruptured Vs Unruptured Aneurysms in Recanalization After Coil Embolization

Background: Aneurysm recanalization is a significant problem in coil-treated intracranial aneurysms. We hypothesize ruptured aneurysms are more likely to demonstrate this phenomenon than unruptured aneurysms.

Methods: This was a retrospective study over 4 years. Initial and follow-up angiography results were reviewed and aneurysm obliteration was classified: I, complete; II, residual neck; III, residual aneurysm; and IV, partial treatment. Recanalization was classified as significant, mild, and none.

Results: Two hundred twelve aneurysms were coiled in 199 patients, of which 180 patients survived to 6 months after treatment. Follow-up angiography (>6 months) was available for 116 (64.4%) aneurysms (44 ruptured, 72 unruptured). Mean angiographic follow-up was 20 months. Recanalization was significant in 16 (13.8%) aneurysms, mild in 23 (19.8%), and absent in 87 (75%). Sixteen aneurysms underwent recoiling. Factors significant for recanalization by univariate analysis were ruptured vs unruptured (53.5% vs 22.5%; P = .001), larger aneurysm size (t test, P < .0001; median, 8-mm cut point, P < .01), aneurysm location (basilar tip and ICA terminus, P < .05), posterior circulation (P < .05), and younger age (t test, P < .05), whereas aneurysm neck size (4 mm) demonstrated a trend (P = .09). Incomplete initial aneurysm obliteration (II-IV, 20.6% vs I, 4.3%; P < .05) was associated with significant recanalization. In multivariate analysis, younger age (age <52 years; OR, 2.4; 95% CI, 0.194-2.08), ruptured aneurysm (OR, 3.2; 95% CI, 1.25-8.13), and larger aneurysm size (OR, 1.14; 95% CI, 1.04-1.24 linearly; OR, 3.5; 95% CI, 1.38-8.72) significantly predicted aneurysm recanalization. Performance of recoiling was significant with larger aneurysm size (OR, 2.0; 95% CI, 0.02-3.25) and younger age (age <52, OR, 2.4; 95% CI, 0.34-3.31) by multivariate analysis, whereas ruptured aneurysm demonstrated a trend.

Conclusions: In multivariate analyses, ruptured aneurysms, larger aneurysms, and younger patient age were significantly associated with recanalization. Larger aneurysms and younger age were significantly associated with recoiling.