Growth-Related Major Recanalization of Coiled Aneurysms: Incidence and Risk Factors.

BACKGROUND: Though endovascular techniques and procedural devices continue to advance, recurrence of embolized aneurysms is still problematic. Enlarging size during follow-up is the presumed basis of recanalization in some lesions, but such growth has not been adequately investigated.

OBJECTIVE: To generate estimates of growth in coiled aneurysms with major recanalization, focusing on incidence and risk factors involved.

METHODS: A cohort of 134 patients harboring 139 aneurysms were retrospectively reviewed, each subjected to re-embolization for major recanalization after initial coil embolization. Cumulative medical records and radiological data were assessed. The aneurysms were grouped by nature of recanalization, either related or unrelated to growth. Growth was defined as >50% increase in aneurysm volume (including coil mass) at the time of re-embolization, compared initial status. Aneurysm volumes were determined by volume of coil mass within full confines of the aneurysm. Univariate and multivariate analyses were performed to identify risk factors predisposing to growth.

RESULTS: Major recanalization was growth related in 74 coiled aneurysms (53.2%) and unrelated to growth (by coil compaction) in 65 (46.8%). Multiple logistic regression analysis indicated that growth of coiled aneurysm was linked to aneurysms initially ruptured at presentation (P = .002) and aneurysm size <7 mm (P < .001). Cumulative growth rates were as follows: 14 (18.9%), 6 mo; 18 (24.3%), 12 mo; 13 (17.6%), 24 mo; 10 (13.5%), 36 mo; and 19 (25.7%), >36 mo.

CONCLUSION: Our data suggest that aneurysms presenting with hemorrhage and small-sized aneurysms (<7 mm) are predisposed major recanalization by growth after coil embolization, as opposed to coil compaction.